Surgically Facilitated Orthodontic Therapy: An Interdisciplinary Approach 9783030900984, 3030900983

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George A. Mandelaris Brian S. Vence Editors

Surgically Facilitated Orthodontic Therapy An Interdisciplinary Approach

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Surgically Facilitated Orthodontic Therapy

George A. Mandelaris  •  Brian S.Vence Editors

Surgically Facilitated Orthodontic Therapy An Interdisciplinary Approach111

Editors George A. Mandelaris Private Practice Periodontics and Dental Implant Surgery Periodontal Medicine and Surgical Specialists, LLC Oakbrook Terrace and Glenview, IL, USA

Brian S. Vence Private Practice Restorative Dentistry Oakbrook Terrace, IL, USA

This work contains media enhancements, which are displayed with a “play” icon. Material in the print book can be viewed on a mobile device by downloading the Springer Nature “More Media” app available in the major app stores. The media enhancements in the online version of the work can be accessed directly by authorized users. ISBN 978-3-030-90098-4    ISBN 978-3-030-90099-1 (eBook) https://doi.org/10.1007/978-3-030-90099-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

This book is dedicated to my wife, Aleka. Without her unconditional love, support, sacrifice, and encouragement, this book would have never been possible. Thank you for always believing in me and being my rock through all of life’s ups and downs. This book is also dedicated to my daughters, Ariana and Anastasia. Believe in your dreams and never let anyone stop you from achieving them. Hard work, dedication, integrity, faith, friendship, and love are the cornerstones of accomplishing anything worthwhile in life. Believing in these cornerstones, you can accomplish anything. I would also like to thank my parents for inspiring and encouraging me to pursue the profession of Periodontics and to never give up on my dreams. For all your sacrifice in raising three sons who all had big dreams and aspirations. Thank you for nurturing us and living by example why family, faith, education, and friendship really matter. To my brothers, Chris and Steve, for always keeping me in line and reminding me of the importance of humility and family. George A. Mandelaris, DDS, MS This book is dedicated to my fiancé Kerri who is patient with my time away from her as I pursue my career commitments. This book is also dedicated to my two daughters, Teagen and Kali. As you pursue your goals, God created you with all the ability and capability to realize your passion and serve Him. As Bob Marley said, “The road of life is rocky, and you may stumble to…” Remember if you are passionate about something don’t give up on yourself, just get your skill set together. Authenticity and integrity are more important for fulfillment and satisfaction in life than trying to please everybody. Serve yourself while serving others and don’t compromise either yourself or your patients. My parents have always been instrumental in supporting and encouraging me. They always let me explore my curiosities, and when I fell, they helped me get up and pushed me in the right direction. My father, a dental technician, was my first mentor in dentistry. Working in his dental laboratory during summer vacations gave me a unique perspective in dental school. The perspective is how do I make the technicians job easier? He also taught me to always honor the sacred nature and privilege of serving patients. Brian S. Vence, DDS

Foreword

In order to appreciate the evolution of the concepts centered around interdisciplinary patient treatment discussed in this book, we need to revisit the vision of Drs. D. Walter Cohen and Morton Amsterdam. Their vision of dual specialization was born out of necessity at the University of Pennsylvania in the 1960s. They realized that collaboration amongst the dental specialties was critical to saving teeth and achieving sustainable oral health. Their vision was unique, bold, and expansive allowing for the incorporation of yet to be discovered knowledge and technologies. There has been an explosive growth in our ability to collect and manage digital information regarding oral and extra-oral aspects of health. Dentistry has evolved to become an important part of medical well-being as well. While the title of this book suggests a detailed description of surgically facilitated orthodontic therapy (SFOT), that is not the entire story. In fact, SFOT is the conduit which leads the relevant dental and medical specialties to interdisciplinary patient care when needed. SFOT enables safe, predictable, and precise modification of dentoalveolar structures to recapture oral health. SFOT can facilitate multispecialty interaction to regain proper space for optimal oral restoration. Arguably, cone beam CT technology (CBCT) has offered the dental specialties the unprecedented opportunity to manage and share complex information in an interdisciplinary manner. This is why section II in Chapter V includes an oral and maxillofacial radiologist discussing interdisciplinary dentofacial therapy. Other types of digital data acquisition are an improvement over existing technology. The sharing of information has enabled more precise diagnosis, prognosis, and treatment planning. The ability to share CBCT information has led to a more meaningful informed consent process, more predictable outcomes, and has fostered a higher level of professional accountability. The editors of this book, Drs. George Mandelaris and Brian Vence, have skillfully assembled authors from medical and dental disciplines to address the comprehensive nature of interdisciplinary dentofacial therapy in five sections. These sections include the embryologic nature of the craniofacial skeleton, patient assessment, orthodontic, periodontic, and maxillofacial perspectives and finally case presentations. By reading this book, you will learn that dental implants are often not a solution to the management of dentofacial abnormalities. Have we given up on teeth? Restoring the dentition to sustainable oral health captures the resilience and adaptability of teeth which cannot be found in dental implants or prostheses they support. Department of Graduate Periodontics University of Illinois, College of Dentistry Chicago, IL, USA

Alan L. Rosenfeld

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Preface

This book was born nearly 15 years ago from a simple question—“what do you think the future of Periodontics is?” From that seminal moment, a journey began between a periodontist and a restorative dentist in a quest to transform and improve conventional interdisciplinary outcomes. Initially, we developed much of our SFOT concepts to help solve the problems encountered with attrition, erosion, tooth migration, and space appropriation limitations when managing the worn dentition. Once we truly understood that SFOT was so much more than moving teeth fast, we took on a mission to use this incredible treatment modality to improve patient outcomes, raise the bar of interdisciplinary dentistry and, ultimately, share our experiences with anyone who would listen. It resulted in a culmination of disciplines and like-minded authors who have contributed their renowned expertise to this project. About the same time we were developing our SFOT concepts and workflows, a paradigm shift was occurring in the profession, creating the perfect storm. Imaging was changing from something that was used only for craniomaxillofacial fractures, pathology, or dental implant surgery using multi-slice spiral computed tomography (typically found at a hospital or stand-­ alone medical imaging centers) to in-office cone-beam computed tomography (CBCT) units. 3D technology and capabilities for more comprehensive information management and better diagnosis was becoming available to every private practice practitioner. In addition, 3D simulation technology was being expanded to no longer just include guided implant surgery applications, but into orthodontic therapy where the entire regional anatomy could be visualized and, most importantly, the influence of tooth movement on the dentoalveolar bone complex was made transparent. These CBCT imaging-based software applications were capable of more clearly defining the orthodontic boundary conditions and the interdisciplinary team had transparency (or “collaborative accountability” measures) in understanding what was, and what was not, capable with traditional tooth movement. Orthodontic simulation software quickly allowed the team to plan tooth movement in a facially generated context, using a biologic compass and periodontal conscience, which also improved communication of treatment needs/limitations/goals to the patient. In short, the playing field was becoming leveled. As a result, expanded opportunities were needed to position the teeth in the correct position for facial esthetics and function but without creating periodontal annuity conditions for gingival recession-based problems. Similarly, airway considerations were given more and more consideration in the prosthodontic discipline to appreciate why patients present with complex dental conditions involving attrition, erosion, tooth migration, and space appropriation limitations. The influence of sleep disordered breathing and regional anatomy findings that impact these conditions required that the profession consider and respect airway dimensions, oral cavity volume, and the entire breathing room compartments in the overall treatment plan when treating and/or rehabilitating patients. It also demanded that we consider the condition and position of the temporomandibular complex, or the so-called back of the system, as equally important as we consider “the front of the system” (i.e., periodontium, teeth). In maxillofacial surgery, the influence of imaging technology for 3D surgical planning was becoming more predictable and popular to improve accuracy and reduce surgical operating times for those patients with dentofacial disharmonies requiring orthognathic surgery. Today, ix

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jaws-jaws and jaws-face planning can be better planned and more accurately delivered using these techniques afforded by CBCT imaging. SFOT does not, in most cases, negate the need for skeletal surgery. However, it does expand orthodontic boundary conditions and can make jaw reconstruction more predictable and less complex (less relapse potential) for dentofacial disharmony patients requiring decompensation measures prior to surgery. It also dramatically improves the periodontal phenotype, something rarely experienced in conventional orthodontic treatment planning measures. In addition, the potential to get a dentition decompensated in a timelier fashion so that a patient with obstructive sleep apnea can get to life-altering orthognathic surgery more efficiently, should not be underappreciated or marginalized. In summary, this book is a patchwork quilt made possible by contributions from some of the best and brightest people representing all the disciplines. It is put together in a way that expands what dentistry is capable of achieving. When the profession practices in a truly team-approach context, everyone wins—especially the patient. Using SFOT, incorporating digital technology into the planning workflow, considering and respecting airway dimensions, and leading the treatment plan from a facial-prioritized approach is the future for interdisciplinary patient care. The answer to the question that was posed over 15 years ago about “what is the future of Periodontics?” is this book. It remains centered on interdisciplinary patient care, supporting prosthodontic and restorative outcome goals, but is now thrust with the charge to expand the scope of practice and limits of patient care by enhancing outcomes and influencing the success of all disciplines, especially that of the patient. For us, this book represents the next generation of interdisciplinary dentofacial therapy by broadening the scope of all the disciplines and demanding that we all work together to achieve outcomes which transcend that of the past. After reading this book, we hope that the purpose of your practice is enhanced and the lives of your patients are improved for the better. Sustainable oral health conditions for a lifetime are the goal. How you go about accomplishing them may soon change. We leave you with the following two questions that this book may help you discover your own answers: 1. How early may we, as dental professionals, diagnose and identify problems at which to intervene with the goal of minimizing the need for more extensive dentistry later in a patient’s life? 2. How long before our profession values an accurate diagnosis and comprehensive treatment planning as much as it does procedures? Oakbrook Terrace and Glenview, IL, USA Oakbrook Terrace, IL, USA 

George A. Mandelaris Brian S. Vence

Acknowledgments

Sir Isaac Newton is quoted as once saying “If I have seen a little further, it is because I have stood on the shoulders of giants.” I want to acknowledge key mentors in my professional education, development, and journey. They are who inspired and enabled me to see a little further. My dental school mentor at the University of Michigan who enthused me to consider periodontics and showed me, by example, the definition of hard work—Dr. Hom-Lay Wang; my post-­ graduate periodontal program director at the University of Louisville who trained me in the fundamentals of the Periodontology specialty discipline—Dr. Henry Greenwell; my former partner in practice for 20 years, Dr. Alan Rosenfeld, for showing me “how to develop a good reputation”; and Dr. Dan Spagnoli, for challenging me to answer the question: “At what level do you want to practice?”. Thank you for your inspiration, guidance, and commitment to my development and to our profession. I will be forever grateful to you for having taken me under your wing, mentoring me, and showing me how to bring out the best of my abilities. I would also like to thank my dental and medical colleagues in the Chicagoland area who have entrusted their patients to our care and for their friendship over so many decades of interdisciplinary patient care. Without your collaboration over all these years, this book could not have been completed. Lastly, I would like to thank the authors of this textbook for contributing their know-how. Your willingness to selflessly share your knowledge, skill, expertise, and to help advance the profession is appreciated beyond what words can express. George A. Mandelaris, DDS, MS My mentors in my field are numerous, and I will attempt to name a few. Jim Hodge was my first meaningful associateship, and he showed me how to run a fee for service dental practice. Jim introduced me to Carl Rieder who founded the Newport Harbor Academy of Dentistry. He offered high quality speakers and an extraordinary continuing education experience. Carl Rieder opened the doors to the two most influential groups for me in dentistry—the American Academy of Restorative Dentistry and The American Academy of Esthetic Dentistry. I discovered the behavioral side of dentistry through Avrom King, and he showed me the courage to be authentic. Aalt Brouwer is an extremely gifted facilitator of dental teams. Bob winter and Don Cornell taught me what the technologist needs on the clinical side for technical excellence on the laboratory side—the dentist creates the space, and the technologist fills the space. Harold Shavell, Frank Spear, and Edward P. Allen shared their knowledge early in my career, so I was on the right path early on. Jim Metz, Jeff Rouse, and Jim McKee helped me with airway and the relationship to occlusion and systemic health. Alan Rosenfeld believed in me as a referring colleague as well as George Mandelaris and David Forbes. Thank you all for being the “ready” teacher when the student appeared. I also want to thank all the authors in the book for selflessly sharing their knowledge. The authors all give without expecting anything in return. These people are true teachers! Brian S. Vence, DDS

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Contents

Part I Embryologic Basis of Bone Formation in the Human Craniofacial Skeleton and Its Relation to Malocclusion in Interdisciplinary Dentofacial Therapy  Embryologic Development of the Jaws�����������������������������������������������������������������������������   3 George A. Mandelaris  Dental Space Deficiency Syndrome: An Anthropological Perspective���������������������������  17 Colin Richman  Bone. The Foundation of a Smile���������������������������������������������������������������������������������������  33 George A. Mandelaris Part II Patient Assessment, Co-discovery, Diagnosis and Planning the Vision  Co-Discovery: A Pathway to Meaningful and Essential Treatment�������������������������������  61 Brian S. Vence Patient Assessment �������������������������������������������������������������������������������������������������������������  67 Brian S. Vence  The IDT Action Plan: Developing and Planning the Vision�������������������������������������������  81 Brian S. Vence  Sleep Disordered Breathing Considerations and Screening in Patient Assessment and Treatment Planning�������������������������������������������������������������������  89 James Metz and Mickey C. Harrison  Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology�����������������������������  97 Mitra Sadrameli, E. Dwayne Karateew, and Mel Mupparapu  Assessing the Temporomandibular Joint Condition in Surgically Facilitated Orthodontic Treatment planning��������������������������������������������������������������������������������������� 113 James McKee Part III The Orthodontic Perspective  The Transverse Dimension: CBCT Treatment Planning in Growing Children��������������������������������������������������������������������������������������������������������������� 129 Claire Ferrari  Goal-Oriented Treatment Planning with Corticotomy-Facilitated Orthodontics����������������������������������������������������������������������������������������������������������������������� 147 Rebecca Bockow

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Pre-surgical Orthodontic Therapy ����������������������������������������������������������������������������������� 161 Drew McDonald  Management of Skeletal Class II Malocclusion: Historical Challenges and New Opportunities����������������������������������������������������������������� 197 Kensuke Matsumoto  Distraction Osteogenesis Maxillary Expansion (DOME) and SFOT for Naso-­Maxillary Expansion in Obstructive Sleep Apnea (OSA) ������������������� 211 Audrey Yoon, Linda Phi, and Stanley Liu  3 D Orthodontic Diagnosis, Planning, and Treatment����������������������������������������������� 217 Randall C. Moles  Digitally Guided Orthodontic Planning and Simulation Including Implant Placement ������������������������������������������������������������������������������������������������������������� 251 Gonzalo Blasi, Ignacio Blasi, and Alvaro Blasi  Digital Smile Design (DSD) and Surgically Facilitated Orthodontic Therapy (SFOT)������������������������������������������������������������������������������������������� 269 E. Todd Scheyer, Daniel Ramos, John Karotkin, Giancarlo Romero, Octavio Cintra, and Andrew M. Rossi Part IV The Periodontal Perspective  Dentoalveolar Bone in Orthodontic Patients: The Periodontal Perspective����������������� 299 Rafael Siqueira, Gustavo Fernandes, Riccardo Di Gianfilippo, and Jeff CW. Wang  Phenotype Modification Therapy: New Challenges and Opportunities ����������������������� 323 Richard T. Kao, Donald A. Curtis, George A. Mandelaris, Colin Richman, Shan-Huey Yu, Katie Goss, and Guo-Hao Lin  Regional Acceleratory Phenomenon in Surgically Facilitated Orthodontic Therapies������������������������������������������������������������������������������������������������������� 339 Kevin G. Murphy  Anesthesia Pain and Anxiety Control for Surgically Facilitated Orthodontic Treatment Procedures���������������������������������������������������������������������������������� 353 Zak Messieha SFOT Surgery��������������������������������������������������������������������������������������������������������������������� 359 George A. Mandelaris  The Use of Temporary Anchorage Devices in Surgically Facilitated Orthodontics����������������������������������������������������������������������������������������������������������������������� 615 Thanos Dounis  Local Applications of Corticotomy and Bone Grafting for Difficult Orthodontic Tooth Movement������������������������������������������������������������������������������������������� 629 I-Ching (Izzie) Wang, Michelle Yuching Chou, and Jeff CW. Wang

Contents

Contents

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Part V The Maxillofacial Perspective  Overview and Perspective of TMJ Surgery in Skeletal Malocclusion��������������������������� 653 Brian Shah  Surgically Facilitated Orthodontic Treatment and Orthognathic Surgery������������������� 695 Robert J. Relle  Contemporary Skeletal Surgery for Obstructive Sleep Apnea��������������������������������������� 709 Stanley Yung Liu, Kevin Lin, and Allen Huang Part VI Putting It All Together. Case Presentations  Case Presentations and Lessons Learned������������������������������������������������������������������������� 719 Brian S. Vence and George A. Mandelaris

Editors and Contributors

About the Editors George A. Mandelaris, DDS, MS, FACD, FICD  Dr. Mandelaris attended the University of Michigan from undergraduate through dental school. He completed a post-graduate residency program at the University of Louisville, School of Dentistry, where he obtained a certificate in the specialty of Periodontology as well as a Master of Science (M.S.) degree in Oral Biology. Dr. Mandelaris is a Diplomate of the American Board of Periodontology and Dental Implant Surgery and has served as an examiner for Part II (oral examination) of the American Board of Periodontology’s certification process. He is a Adjunct Clinical Assistant Professor in the Department of Graduate Periodontics at the University of Illinois, College of Dentistry (Chicago, IL) and an Adjunct Clinical Assistant Professor at the University of Michigan, Department of Periodontics and Oral Medicine (Ann Arbor, MI). Dr. Mandelaris is a Fellow in both the American and International College of Dentists. Dr. Mandelaris serves as an ad hoc reviewer for the Journal of Periodontology and the International Journal of Oral and Maxillofacial Implants. In 2021, he was appointed as an Editorial Consultant to the International Journal of Periodontics and Restorative Dentistry. He has published over 40 scientific papers in peer-reviewed journals and has authored eight chapters in seven different textbooks used worldwide on subjects related to computer-guided implantology, CT/CBCT diagnostics, and surgically facilitated orthodontic therapy (SFOT). Dr. Mandelaris is a two-time recipient of the American Academy of Periodontology’s (AAP) Clinical Research Award (2017, 2021), an award given to the most outstanding scientific article with direct clinical relevance in Periodontics. A nationally recognized expert, he was appointed by AAP to co-chair the Best Evidence Consensus Workshop on the use of CBCT Imaging in Periodontics as well as co-author the academy’s guidelines. In 2018, he was recognized with American Academy of Periodontology’s Special Citation Award. Dr. Mandelaris is the 2018 recipient of The Saul Schluger Memorial Award for Clinical Excellence in Diagnosis and Treatment Planning. Dr. Mandelaris currently serves on the American Academy of Periodontology Board of Trustees and has served as a Past

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President of the Illinois Society of Periodontists. He is a key-­ opinion leader for several industry leaders and holds memberships in many professional organizations, including the American Academy of Periodontology, Academy of Osseointegration, and the American Academy of Restorative Dentistry. Dr. Mandelaris is in private practice at Periodontal Medicine & Surgical Specialists, LLC in Glenview and Oakbrook Terrace, IL, USA. He limits his practice to Periodontology.

Brian S. Vence, DDS  Dr. Vence maintains a private practice in Oakbrook Terrace, Illinois with a special interest in comprehensive esthetic and restorative dentistry. He graduated with a degree in honors biology in 1981 from the University of Illinois, Champaign-Urbana. He received his dental degree in 1985 from the University of Illinois School of Dentistry at the Medical Center in Chicago. He completed a hospital residency at the VA Wadsworth-UCLA in 1986 and a mini-residency in temporomandibular joint disorders. Dr. Vence founded the Chicago Academy of Interdisciplinary Dentofacial Therapy in 1992, a study club designed to define and promote excellence in dentistry. He has had manuscripts published in Quintessence of Dental Technology, Practical Periodontics and Aesthetic Dentistry, The Journal of Prosthetic Dentistry, Compendium, and the Journal of Esthetic and Restorative Dentistry. He is a member of the American Academy of Restorative Dentistry, the American Academy of Esthetic Dentistry, the International College of Dentists and the American College of Dentists, American Dental Association, American Thoracic Society, Seattle Study Club-Oakbrook. He is a past president of the Fox River Valley Dental Society in Illinois.

Contributors Alvaro Blasi  Private Practice, Blasi Clinic, Barcelona, Spain Augusta University Dental College of Georgia in the Oral Rehabilitation Department, International University of Catalonia (UIC), Barcelona, Spain Gonzalo Blasi  Private Practice, Blasi Clinic, Barcelona, Spain Department of Periodontics, UMB and UIC, Barcelona, Spain Ignacio Blasi  Private Practice, Virginia, USA Private Practice, Barcelona, Spain University of Maryland, Department of Orthodontics, Barcelona, Spain Rebecca Bockow, DDS, MS  Private practice limited to orthodontics and periodontics, Seattle, WA, USA Department of Orthodontics, University of Washington, Seattle, WA, USA Michelle Yuching Chou  Department of Developmental Biology, School of Dental Medicine, Harvard University, Boston, MA, USA

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Octavio Cintra  Private Practice, Sao Paulo, Brazil Donald A. Curtis  Preventive and Restorative Dental Science, University of California San Francisco, San Francisco, CA, USA Gustavo Fernandes  Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA Claire Ferrari  Private Practice, Ferrari Orthodontics, Berkeley, CA, USA Riccardo  Di Gianfilippo Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA Katie Goss  American Academy of Periodontology, Chicago, IL, USA Mickey C. Harrison  The Metz Center, Columbus, OH, USA Allen  Huang Division of Oral and Maxillofacial Surgery, LAC + USC Medical Center, Los Angeles, CA, USA Richard T. Kao  Orofacial Sciences, University of California San Francisco, San Francisco, CA, USA Private Practice, San Jose, CA, USA E. Dwayne Karateew  University of Illinois at Chicago, Chicago, IL, USA John Karotkin  Private Practice, Houston, TX, USA Guo-Hao  Lin Orofacial Sciences, University of California San Francisco, San Francisco, CA, USA Kevin Lin  Department of Otolaryngology/Head & Neck Surgery, Baylor College of Medicine, Houston, TX, USA Stanley Liu  Division of Sleep Surgery, Department of Otolaryngology-Head & Neck Surgery, School of Medicine, Stanford Univeristy, Stanford, CA, USA Stanley Yung Liu  Division of Sleep Surgery, Department of Otolaryngology - Head & Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA Stanford Health Care, Stanford, CA, USA George A. Mandelaris  Department of Graduate Periodontics, University of Illinois, College of Dentistry, Chicago, IL, USA Department of Periodontics and Oral Medicine, University of Michigan, School of Dentistry, Ann Arbor, Michigan, USA Private Practice, Periodontics and Dental Implant Surgery, Periodontal Medicine & Surgical Specialists, LLC, Glenview and Oak Brook Terrace, IL, USA Private Practice, Oakbrook Terrace, IL, USA Kensuke Matsumoto  Matsumoto Orthodontics & Periodontics, Wilmington, NC, USA Drew McDonald  Private Practice limited to Orthodontics, Albuquerque, NM, USA James McKee  Private Practice, Downers Grove, Illinois/Spear Education Center (Scottsdale, AZ), Downers Grove, IL, USA Zak  Messieha Office Anesthesiology & Dental Consultants, PC Office-Based Anesthesia Services, Oakbrook Terrace, IL, USA James Metz  The Metz Center, Columbus, OH, USA

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Randall C. Moles  Private Practice Limited to Orthodontics, Racine, WI, USA Mel Mupparapu  University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA Kevin  G.  Murphy Department of Periodontics, Baltimore College of Dentistry at the University of Maryland, Baltimore, MD, USA Baltimore Dental Arts, Baltimore, MD, USA Thanos Dounis  Private Practice limited to Periodontics and Dental Implant Surgery, Synergy Periodontics and Implants, Fredericksburg, VA, USA Linda Phi  Department of Orthodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, CA, USA UCLA Section of Orthodontics, Los Angeles, CA, USA Daniel Ramos  Pozuelo de Alarcón, Spain Department of Orthodontics, Faculty of Dentistry, Pontificia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil Robert J. Relle  Private practice, Oral and Maxillofacial Surgery, Los Angeles, CA, USA Colin Richman  Department of Periodontics, Augusta University, Augusta, GA, USA Georgia School of Orthodontics, Atlanta, GA, USA Private Practice, Atlanta, GA, USA Giancarlo Romero  Private Practice, Bellaire, TX, USA Andrew M. Rossi  Private Practice, Houston, TX, USA Mitra Sadrameli  Private practice, Chicago, IL, USA E. Todd Scheyer  Private Practice, Houston, TX, USA University of Texas, San Antonio, TX, USA Brian Shah  St. Petersburg, FL, USA Rafael Siqueira  Department of Periodontics, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA Brian S. Vence  Private Practice, Oakbrook Terrace, IL, USA I-Ching (Izzie) Wang  Department of Periodontics, College of Dentistry, University of Iowa, Iowa City, IA, USA Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA Jeff  CW.  Wang Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA School of Dentistry, Taipei Medical University, Taipei, Taiwan Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA Graduate Institute of Clinical Dentistry, National Taiwan University, Taipei, Taiwan

Editors and Contributors

Editors and Contributors

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Audrey Yoon  Department of Psychiatry and Behavioral Science, Stanford Center for Sleep Science and Medicine, Stanford University, School of Medicine, Stanford, CA, USA Sleep Medicine Clinic, Stanford University, Redwood City, CA, USA Department of Orthodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, CA, USA UCLA Section of Orthodontics, Los Angeles, CA, USA Shan-Huey  Yu  Periodontics and Oral Medicine, University of Michigan, Ann Arbor, MI, USA

Part I Embryologic Basis of Bone Formation in the Human Craniofacial Skeleton and Its Relation to Malocclusion in Interdisciplinary Dentofacial Therapy

Embryologic Development of the Jaws George A. Mandelaris

 he Embryologic Basis for Bone Formation T in the Human Craniofacial Skeleton Introduction A thorough understanding of embryologic and developmental processes leading to craniofacial anatomic development is essential to appreciate—and therapeutically reestablish— the homeostatic balance essential for oral and periodontal health, occlusal stability, and esthetics. This is particularly true if one is to be successful at sustainable bone regeneration, augmentation, or bone construction efforts which is the key concept of this chapter (and book) when discussing surgically facilitated orthodontic therapy as well as the surgical outcomes of dentoalveolar bone augmentation (whether for implant, natural teeth, or a combination of both). The intricate details of embryogenesis of the craniofacial skeleton and the impact of epigenetic processes influencing individual response to surgically facilitated orthodontic therapy (SFOT) surgery are not the intent of this chapter, but rather to acknowledge its vital role in treatment planning. As one of my mentors once told me: “If you want to learn how to grow bone, you must understand how it developed in the first place” (Dan Spagnoli, DDS, PhD. Oral and Maxillofacial Surgery; Southport NC, USA).

Embryology of the Craniofacial Bones [1] The developing craniofacial complex consists of basal bone (i.e., the static bone/portion) and alveolar bone (i.e., the dynamic bone/portion), the latter which is intimately involved in tooth development. G. A. Mandelaris (*) Private Practice, Periodontics and Dental Implant Surgery; Periodontal Medicine & Surgical Specialists, LLC, Glenview and Oak Brook Terrace, IL, USA e-mail: [email protected]

The dynamic bone/portion consists of the developing alveolar processes that ultimately encrypt the developing tooth germs, and generally precedes the development of the static portion/bone that ultimately forms the main structural osseous components of the craniofacial complex. At recurring points in embryogenesis, formative osseous events related to the regional components of the neurovascular bundle delineate the developing basal and dynamic compartments. Factors affecting craniofacial morphology include genetic predispositions toward a broader and shorter (brachycephalic), narrower and taller (dolichocephalic), or an intermediary like craniofacial morphology phenotype, mesocephalic.

Development of the Maxilla and Mandible The maxilla and mandible develop from the first pharyngeal arch, which expands in a lateral-to-medial direction from the mesoderm of the embryo, beginning at approximately the middle of the fourth week of gestation. The first arch forms anterior to the buccopharyngeal membrane, which delineates the floor of the future oral cavity, which is ultimately formed by the first, second, and third pharyngeal arches [1]. At this point, the first arch forms the maxillary and mandibular processes, which cover the developing forebrain laterally and ventrally, respectively [1]. The developing oral cavity is further delineated cranially by the frontal (bone) prominence. The face begins to develop between 24 and 38 days of gestation, at which time the epithelium on the inferior border of the fusing maxillary and medial nasal processes and the superior border of the mandibular arch (the inferior border of the first pharyngeal arch) begins to proliferate and thicken. These opposing maxillary and mandibular epithelial regions then form the arch-shaped plates of odontogenic epithelium. The newly formed maxillary processes continue to grow medially and converge with the medial and lateral nasal pro-

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_1

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cesses, which develop from mesenchyme within ectodermal thickenings of the frontal prominence and proliferate ­downward. The maxilla develops in close proximity to the cartilage of the nasal capsule and is also associated with a secondary cartilage (the malar cartilage); however, it is not associated with a primary arch cartilage, as is the developing mandible [2]. The lateral and medial nasal processes develop from this frontal prominence and ultimately give rise to the middle portion of the nose, the upper lip, and the anterior portion of the maxilla and the primary palate. The secondary palate begins forming between seven and eight weeks of gestation, from the nasal septum, and the right and left palatine shelves, which extend from the maxillary process toward the midline, thus establishing a boundary between the oral and nasal cavities [1]. Ossification of the maxilla centers on the angle between two branches of the developing infraorbital nerve, spreading posteriorly below the orbit, anteriorly toward the future incisors’ location, and upwards to form the frontal process. This ossification pattern results in formation of a trough around the infraorbital nerve. From this trough, ossification spreads to the palatine process, contributing to the formation of the hard palate. Concurrently, the lateral alveolar plate grows downward from this groove, while the medial alveolar plate grows from the junction of the developing palate and body of the maxilla. Together, these two alveolar plates form the maxillary alveolar process, the dynamic bony structure that encapsulates the developing tooth germs in their bony crypts and largely precedes the development of the body of the maxilla [2]. The maxillary sinus begins to develop during the 16th week of gestation and continues to increase in size until well after birth [2]. Prior to the appearance of the early mandible, Meckel’s cartilage can be seen just medial to the future site of the mandible development. The fibers of the mylohyoid muscle are directed toward this site. The mylohyoid and its associated trigeminal nerve branch are present before the appearance of the mandibular bone to which the muscle will eventually attach. This early appearance of the muscle-nerve unit, and the adjacent cartilage bar, are consistent features of embryologic development [3] (Fig. 1a–e). During the fourth week of development, the mandible can be observed forming within a space previously occupied by soft tissue. Importantly, the mandible does not form within a cartilage precursor; it forms de novo within a specific, appropriate zone adjacent to the central core of the pharyngeal arch complex, which consists of cartilage bars that condense from the ectomesenchyme resulting from the invasion of pharyngeal arch mesoderm by neural crest cells. The cartilage of the first arch is known as Meckel’s cartilage [1]. It is important to note that while Meckel’s cartilage exists in parallel with the developing mandible, it makes no

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direct contribution to it, and ultimately diminishes in volume to become the sphenomandibular ligament. The two cartilages remain separated at midline junction of the mandibular processes by a thin band of mesenchyme [1]. During the sixth week of gestation, an intramembranous ossification center forms from ectomesenchyme at the junction of the incisive and mental branches of the developing inferior alveolar nerve. At 7 weeks, this ossification extends along Meckel’s cartilage anteriorly toward the midline, and posteriorly toward the junction of the lingual and inferior alveolar nerve branches. From this, bony enclosure of the developing neurovascular bundle along the lateral aspect of Meckel’s cartilage occurs and the medial and lateral alveolar plates form. Enclose the developing mandibular tooth germs, that occupy a secondary bony trough, which in itself is partitioned into compartments containing the individual tooth germs [1].

Development of the Periodontium Development of the periodontium begins as an early process during the development of the dynamic portion of the dynamic (alveolar) bone. Cho and Garant [4] have summarized this process. The tooth germ (typically envisioned at the cap stage) comprises the enamel organ, the dental papilla, and the dental follicle, ultimately arises from dental ectomesenchyme, which migrates from streams of neural crest cells that invade the developing maxillary and mandibular perifollicular mesenchymal tissues. Reciprocal induction and differentiation processes within these neural crest-derived tissues ultimately give rise to the primordial oral epithelium. Neural crest cell subsets give rise to chondrocytes, osteoblasts (lining the developing alveolar process [5]), periodontal ligament fibroblasts (which proliferate during root development from perifollicular mesenchyme), cementoblasts, and dentin-forming odontoblasts [4]. Cementum is an avascular mineralized tissue that develops after the differentiation of root odontoblasts from the dental follicle, along with Hertwig’s epithelial root sheath, which arises from the cervical loop between tissues of the dental papilla and dental follicle [5], between the pre-­ odontoblasts of the dental papilla and the dental follicle [4]. This sheath disintegrates after odontoblast differentiation. As they move toward the developing predentin surface being produced by the odontoblasts, the precementoblasts produce collagen fibrils, which form Sharpey’s fibers, which ultimately anchor the ligamentous portion of the dentogingival complex into the surface of the alveolar bone [4]. Acellular and cellular cementum are both deposited, in opposite directions, depending upon directional migration of the cementoblasts toward the periodontal ligament, as the cemento-

Embryologic Development of the Jaws

a

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b

Meckel’s cartilage

Dental follicle and enamel organ

Mandibular nerve

Lingual branch

Inferior alveolar branch

Developing mandible

Inferior alveolar nerve

Developing mandible Incisive branch

Meckel’s cartilage

Mental branch

Initial site of osteogenesis

c

d

Nasal

Nasal capsule

Sphenoid

Cranial base

Premaxilla Maxilla

Meckel’s cartilage

Zygomatic Mandible

e Superior alveolae nerve Maxillary nerve Developing maxilla

Maxilla

Mandibular nerve

Meckel’s cartilage Arch I

Developing mandible

Arch II Arch III Arch IV

4 Weeks

Initial sites of osteogenesis

Lingual nerve Former site of Meckel’s cartilage

Inferior alveolar nerve Mental nerve

16 Weeks

Fig. 1 (a) Embryogenesis of the static mandibular skeletal bone. (b) Early embryogenesis of the static mandible body and dynamic portion of the mandible which will house the periodontium/dentition. (c) Early

Mylohyoid nerve

Mandible

33 Weeks

embryogenesis of the craniofacial skeleton. (d) De novo bone formation of the craniofacial skeleton. (e). Early appearance of the muscle-­ nerve unit and the adjacent cartilage bar in embryologic development.

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blasts secrete cementoid. Nonmigratory cementoblasts become cementocytes, associated with cellular cementum [5]. Gingival tissues comprise connective tissue and morphologically specialized epithelium for adaptation to the tooth and alveolar bone surfaces. The reduced enamel epithelium of the developing and erupting tooth fuses with the developing oral epithelium and is transformed to establish the dentogingival junction (junctional epithelium cells). Upon contact with the tooth surface, they form a basal lamina that adheres to the tooth surface via hemidesmosomes [4] (Fig. 2a–c). As it matures, gingival connective tissue is organized into 9 fibers of the periodontium including: transseptal, circular,

a

semicircular, transgingival, dentogingival, dentoperiosteal, alveologingival, intercircular, and interpapillary fibers [4] (Fig. 3). Through the work of E.P.  Harvold and colleagues [6], considerable evidence has been accumulating that consistently, during embryogenesis, demonstrates that the nerve in any given anatomic structure develops first, followed by muscle and bone. A central tenet of Harvold’s theories focuses on bone–muscle interaction, in which the central nervous system regulates bone formation in a specialized physical environment, with developing muscles as intermediaries (Fig. 4).

b

c

Fig. 2 (a) Embryogenesis of the dynamic alveolar bone/tooth portion of the jaws. Dental follicle and perifollicular mesenchyme. (b) Development of the dynamic alveolar bone/tooth portion of the jaws. (c) Development and eruption of the tooth and periodontium

Embryologic Development of the Jaws

7 Alveologingival fibers

Dentogingival fibers

Inter-papillary fibers

Trans-septal fibers

Dentogingival fibers Dentoperiosteal fibers

Intergingival fibers

Circular and semicircular fibers

Fig. 3  9 gingival fibers of the periodontium

Fig. 4  The periostealendosteal-­Sharpey fiber structural continuum

Transgingival fibers Intercircular fibers

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 ommon Goals of Embryogenesis, C Constructive and Reconstructive Therapy In dentoalveolar bone engineering surgery, the clinician is well advised to distinguish between RECONstructive surgery and CONstructive surgery. Contemporary bone grafting surgery incorporates consideration on how various components of the neuromuscular system, a la Harvold—i.e., will heal/form. In this model, one considers the central nervous system (CNS) in its primary role of control over embryogenesis. Redeveloping what was once there. Reconstructive surgery implies one is remedying a lack of teeth or tissue. However, to meet today’s standards of bone volume, recapitulating or approximating this process therapeutically often involves going beyond normal anatomy, because “normal” anatomy might not constitute what’s required for implant placement, regeneration, and reconstruction. A colleague and strong proponent of Harvold’s research, Chin [3, 7, 8] differentiates “reconstructive therapy” from “constructive therapy” in that the former replaces craniofacial or dentoalveolar structures that were once present, whereas the latter (far more challenging for the clinician) seeks to create de novo that which never developed embryogenically [3]. From reconstructive and homeostatic standpoints, Chin makes the further argument that no volume of bone inserted into a deficiency can be maintained unless incorporated into a preexisting and functional neuromuscular system—which establish and maintain newly constructed skeletal structures in a steady state, called the periosteal-endosteum-Sharpey fiber continuum [3] (Fig. 4). Thus, the objectives of embryogenesis and reconstructive surgery are essentially the same: to establish and maintain newly fabricated skeletal structures within which vascularized bone is innervated and influenced by muscle approximation and can be maintained over time. These statements underscore the pivotal influence of the central nervous system over the development of muscles and skeletal structures in the area of the nerve’s distribution, as an integral part of the ongoing continuum of embryogenesis. The development of this new unit is referred to as the functional matrix [3, 7, 8]. Miller [6] described this primacy of influence of the central nervous system over muscular and skeletal development and states that muscle function originates from the central nervous system (particularly the brain) which generates signals with the proper frequency and amplitude patterns, thus providing the origin of directive oversight of embryogenesis. And, in turn, bone development requires the presence of functioning muscle. Central nervous system is ultimately responsible for [3, 6].

G. A. Mandelaris

Miller further hypothesized that the periodontal ligament may mimic the actions of muscle in this regard, observing the behavior of the dynamic bone formation model, in which bone forms adjacent to developing teeth, to create the alveolar process in the absence of an extrinsic muscle attachment per se. Thus, the periodontal ligament, with its insertion of Sharpey’s fibers into bone, mimics the action of a developing muscle attachment. This could also be a special condition in parallel with the formation and eruption of teeth.

 pigenetic Factors Influencing Development E of the Maxilla and Mandible Epigenetics can be defined as the science or study of the mechanics and effects of modification of qualitative, quantitative, and variable DNA-regulated gene expression by means of environmental and/or other external physicochemical influence on histones or other DNA-associated components (often referred to as “epigenetic marks”), without actually altering the DNA sequence. Published information on the influence and significance of epigenetics specific to the development of the human craniofacial skeleton and bone morphology is extremely scarce [9–13]. However, specific genetic anomalies, such as 22q12.1 deletions encompassing the MN1 gene, have been observed in association with craniofacial anomalies such as cleft palate, as well as maxillary protrusion and retromicrognathia, described in a case report by Bosson et al. [9] Clinical reports of CBCT use in conjunction with craniofacial epigenetic dynamics are scarcer still. In one published case that describes 3D analysis derived from CBCT scans, Belfor [14] recently identified craniofacial changes in “nongrowing adults” treated with the Homeoblock orthodontic airway appliance and attributed them to gene expression, i.e., an epigenetic response induced by this specific treatment. Calic et al. published a study on the possible epigenetic etiologies of bruxism [10] and posit a degree of overlap between this condition and other genetic disorders that have characteristic craniofacial presentations, and that are also thought to have epigenetic etiologies (and in some cases, treatments [15, 16]), namely, Angelman’s syndrome [17], Prader-Willi syndrome [15, 18, 19], and Rett syndrome [16, 20–22]. Interestingly, these syndromes are not infrequently associated with autism spectrum disorders [15, 19, 23–25]. There are numerous recent reviews on epigenetics relative to the clinical setting in general. Among them is a basic overview of the rapidly growing scope of discovery of epigenetic mechanisms underlying the development of human diseases by Zoghbi and Beaudet [26]. Paluch et  al also provide an

Embryologic Development of the Jaws

introductory discussion of epigenetics for clinicians, with a focus on DNA methylation (one of the most commonly studied epigenetic mechanisms), in the context of hematologic malignancies [27]. Summarized in a recent review by Ozkul and Galderisi [28], the scope of epigenetic research encompassing progenitors such as mesenchymal stem cells is rapidly expanding. The authors review studies of specific implications involving osteocyte, chondrocyte, and adipocyte differentiation, in the context of studies of the most extensively studied epigenetic mechanisms, namely histone acetylation, DNA methylation, and micro-RNA (miRNA) expression [28]. Another review by Consalvi et al discusses the promise of muscle progenitor stem cells in the regenerative context, but theorizes based on work with exosome-based noncoding miRNAs [29]. In terms of mandibular development specifically, Rot et al call attention to the combined influences of not only mechanotransduction, but also secretory influences of developing muscle on the formation (or malformation) of the mandible [11]. Using mouse bioinformatics databases, they identified several genes involved in mandibular development that they hypothesize could respond to reciprocal epigenetic interactions [11]. Epigenetics is being evaluated as an emerging front in dentistry that is aligning with personalized medicine [30, 31]. Because craniofacial anomalies are among the most prevalent of developmental defects, an increasing call is emanating from the genetic community for greater resource application to the epigenetic bases of these conditions [32].

I mplications of Normal Anatomy and Tooth Loss  requency, Causes, and Consequences of Tooth F Loss in the Adult Human The commonality between embryogenesis and the practicality of the surgical treatment-planning process is rarely considered in engineering the dentoalveolar bone complex for patients. Chin uses a two-case series [7] to demonstrate unusual and challenging scenarios leading to tooth or implant loss and proceeds to enumerate a series of guidelines that observe the basic principles of embryonic osteogenesis that must be followed in order to replace them. He describes these principles further in a chapter of his book [3], invoking the extreme clinical challenge of constructive surgery, which aims to establish, de novo, a necessary structure that embryogenesis never created, which can also apply to missing teeth, as the consequences to the patient are similar in both scenarios.

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While global tooth loss has declined markedly between 1990 and 2010 [33], severe periodontitis [34] and caries remain prevalent [35], and incidences of both have remained static over this same period [34, 35]. Importantly—and somewhat paradoxically, in view of the global decline in tooth loss—these trends likely presage increased global burdens in both caries and periodontitis in the coming decades [33–35]. Thus, severe periodontitis [34, 36–40] and untreated caries [36, 39, 41] will almost certainly continue to be major contributing factors to tooth loss. Smoking is another key variable that continues to accumulate a progressive body of documentation regarding its impact on the periodontal diseases [40, 42–54]. Less common genomic (e.g., IL-1 genotype [55, 56]), infectogenomic [57], epigenetic [58] or developmental or degenerative disorders that affect the dentoalveolar-skeletal complex are also likely to present the surgical practitioner with challenging constructive and reconstructive scenarios. Predictive value of certain periodontal disease-related parameters has been identified, [47] and an alveolar-ridge classification system (although primarily for the maxillary arch) making use of CBCT measurements relative to periodontal and restorative treatment planning has been proposed by Kao and Fiorellini [59] (Fig. 5). Based on their classification of residual ridges [60], consequences of tooth loss in the adult human have been reviewed by Cawood and Howell with consideration of mucosal and muscle attachments [61]. The six stages of residual ridge resorption are noted in Fig. 6. Utility of CBCT imaging has subsequently been documented. [62–65] The predictive role of CBCT evaluation and modeling has been reasonably well studied over the past decade in regard to preoperative treatment planning for prospective implant placement [66–69] and maxillary sinus augmentation [67], and in retrospective studies by Braut et al for the preoperative evaluation of the posterior mandibular ridge for the presence of lingual undercuts [70], as well as for the dentate mandible [68]. The evolution—and expectation—of implants as the emerging standard of care has led to the development of interventional and interceptive clinical modalities to address the broad variety of resorptive patterns facing the interdisciplinary clinical team and, in the pre-extraction setting, preserve the integrity of the socket whenever possible, as described by Araujo et al. [63, 71] and by Mandelaris and Lu [72]. The aim of socket preservation is to obviate the need to rebuild lost bone volume from a geometric width and height perspective, and preserve structures that are critical for implant positioning that will function harmoniously under long-term stress and strain patterns.

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Fig. 5  The interarch ridge classification of Kao and Fiorellini proposed to aid in restorative and surgical cases requires decision-­making in interdisciplinary dentofacial and implant therapy

 valuating and Intercepting Resorptive E Patterns Historically, the usual course has been to remove teeth with equivocal prognoses, place fixed partial dentures (FPDs) or employ other replacement strategies, and simply allow resorption patterns to happen. Forestalling the pattern of alveolar bone loss involves efforts on the clinician’s part to intercept these resorptive patterns such that therapeutic interventions are not needed. In the preexisting post-extraction/resorption scenario (presenting partially or completely edentulous ridges), the next logical step for the clinician is to classify the resorption diagnostically.

The most commonly used classification systems for alveolar-­ridge resorptive patterns, is that of the International Team of Implantologists (ITI) [73] or from Cawood and Howell [60] (Fig. 6) depending on what method the clinician subscribes to. The International Team for Implantology (ITI) classification of residual ridges (and regenerative potential of each) is the most widely cited classification system worldwide. The ITI classifies bone based on morphology: height, width, resorption patterns (Fig. 7). In 1988, Cawood and Howell published their own classification of edentulous alveolar ridges (based on an evaluation of 300 dried skulls), seeking to simplify and systematize the dynamic and significant changes that occur in the alveolar

Embryologic Development of the Jaws

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Fig. 6  Tooth loss and associated 6 residual ridge resorption stages of Cawood and Howell

Normal Ridge

→

Complete Loss of Ridge

Fig. 7  The International Team for Implantology (ITI) classification of residual ridge resorption/alveolar bone defects, defining the typical pattern of resorption that an alveolar crest will undergo in the wake of tooth extraction

process over time, despite stability of basal bone [60] (Fig. 6). The use of CBCT imaging in regional anatomy assessment has transformed the profession and now allows for meaningful surgical planning based on prosthetic outcome goals as well as more global considerations in comprehensive treatment planning. In fact, it has (in part) helped reshape comprehensive treatment planning altogether.

Whether treatment planning for teeth or implants, strong emphasis belongs on the need to have a quantitative and qualitative assessment of bone, especially marrow quality and vascular potential, regardless of its appearance on a plain digital radiograph, as these images can misrepresent some features, especially the trabecular patterning and its relation to overall marrow quality and vascular potential.

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When tooth loss occurs, post-extraction resorption is inevitable. However, resorption patterns differ between the maxilla and the mandible, and between anterior and posterior segments. Reconstruction and constructive surgical applications in the management of these natural occurring phenomena should represent a thought process more consistent with “tissue engineering” principles.

The Importance of Socket Grafting in Maintaining Physiologic Proportional Ridge Volume The evolution and importance of socket bone grafting preservation and criteria for success have been described by Araujo et  al. [71], who review and document publications that have characterized the pronounced vertical, horizontal, and volumetric changes that occur to the dentoalveolar process following tooth extraction. They cite, in particular, the reduction in ridge volume caused by resorption of the buccal cortical plate (which is prevalently deficient to begin with, as emphasized by Braut et al. [65]), the pronounced reduction in horizontal ridge volume (as opposed to moderate reduction in vertical volume), the predisposition to severity of this phenomenon in the maxilla versus the mandible, the need for atraumatic extraction, and the need for mindfulness not only regarding the significant sequelae of extraction, but also the need for strategies to prevent them, and thus preserve ridge volume overall [71]. In a randomized clinical trial of 28 subjects, Araujo et al (2014) also offer a strategy (involving xenograft placement in fresh maxillary extraction sockets, or not), which resulted in a much lower post-extraction reduction in hard tissue cross-sectional area (25% control versus 3% for the xenograft group), as determined by separate CBCT scans immediately post-extraction and after 4 months of healing [63]. Loveless et al identified a significant difference in CBCT densities using HU in grafted versus ungrafted sockets, but in the posterior maxilla only [74]. Mandelaris and Lu (2015) have also used a putty-based dispersed form of demineralized bone matrix combined with proteins possessing osteoinductive properties (Accell®, Keystone Dental, Burlington, MA), for successful preservation of fresh extraction sockets, and published histologic findings documenting new bone growth at regenerated sites into which implants were successfully placed (based upon bone cores and CBCT imaging) [72].

 he Functional Matrix Concept: Signaling Among T Tissues by a Unifying Conduction System The functional matrix comprises sources of neuromuscular signaling within a regeneration site.

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The functional matrix hypothesis was first advanced by Moss (1997), who described it in terms of mechanotransduction and biologic network theory [75], an “osseous connected cellular network,” [76] genomics [77], and epigenetics [78]. Its overarching theme is one of tissues outside of bone producing effects on bone growth, which has striking elements in common with mechanotransduction/tensegrity and the fiber network systems discussed below. In the 1970s, orthodontist E.P. Harvold pioneered a theory that juxtaposed the biologic processes of craniofacial embryogenesis with the surgical treatment of craniofacial disorders, to advance the concept of surgical engineering [79]. Drawing upon his own research with non-human primates and what he observed in then-current craniofacial surgical practice, Harvold noted that skeletal surgical interventions generally failed to recognize effects of the input from muscle and nervous tissues when considering the desired healing outcome [79]. Dr. Martin Chin, a student of and strong proponent of Harvold’s theories, has expanded upon this concept to further elucidate the use of embryogenic principles in oral and maxillofacial surgery [3], and has also described treatment methods that make use of a poorly understood signaling conduction system by which nerve, muscle, bone, and probably other tissues communicate, specifically, to utilize the existing teeth and periodontium to produce tissue-engineered outcomes by applying the conductive and infiltrative properties of Sharpey’s fibers in the bone generation process [7, 8]. Citing a histochemical study of undecalcified mouse, ox, and human bone by Aaron and Carter, which observed such a fiber network system within the bone that interfaces with periosteum, muscle insertions, and most likely periodontal ligament [80], he hypothesizes that this network might represent an anatomic component of the “functional matrix concept” that has been previously unrecognized [7] (Fig. 4). Bone formation follows a specific set of rules. In order to form and maintain a skeletal unit, the environment into which bone develops must include four essential components (as described by Harvold [79]): (a) An anatomic volume sheltered from physical force (b) A source of bone-forming cells (c) A source of neuromuscular input (d) An absence of pathology Chin published a case series [7] to illustrate successful treatment of two challenging cases in the context of what he called an “unrecognized component of the functional matrix concept” that makes effective clinical use of physiologic sources of neuromuscular signaling within the regenerative site. This illustrates what Chin describes as “constructive surgery,” which can allow the clinician to establish and maintain osseointegration with a functional matrix [7].

Embryologic Development of the Jaws

Simultaneous consideration of the ITI classification [73] of alveolar resorption and functional matrix concepts as described by Chin [3, 7, 8] can provide the clinician with an illuminating perspective. Chin further notes that the specific details of the communication process (the “language”) along such a multi-system pathway have yet to be deciphered [7]. The functional matrix concept is discussed elsewhere in this chapter in the contexts of mechanotransduction and tensegrity when planning and performing surgery involving bone augmentation.

Classification of Residual Ridge Resorption Bone can be classified based on morphology, including height and width and resorption patterns. Figures 6 and 7 illustrate the two most common classification patterns used in the profession today—the Cawood and Howell residual ridge classification and the International Team for Implantology (ITI) classification. When assessing these variables, the clinician is well advised to consider the following questions: (a) Is either ridge partially—or completely—edentulous? (b) What is the normal ridge morphology? (c) What is the desired ridge morphology to accommodate prosthodontics or optimize articulation in a fully dentate individual with a malocclusion? (d) What are the different types of bone deficiencies? (e) What are the types of grafts that can be applied, bearing “normal” in mind? (f) How can the clinician best realize as close to an ideal augmentation outcome as possible? …and (g) How does the clinician analyze that outcome through imaging diagnostic modalities? Case-type patterns can provide useful guidance, such as those published by: (a) Mecall and Rosenfeld (series of papers in prosthetically directed implant therapy) [81–85] (b) Also published in 2006 by Rosenfeld, Mandelaris, and Tardieu [86–88]. (c) Five case-type patterns described by DeGroot and Mandelaris in conjunction with a scanning appliance. A diagnostic wax-up is duplicated in a stone model, optically scanned, and regional anatomy can be studied in terms of prosthetic outcome goals [89]. (d) Basic craniofacial shape/form/phenotype (brachyce phalic, dolichocephalic, mesocephalic) can have a bearing on stress/forces applied to implant areas.

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After using these methods to assess regional anatomy in terms of outcome, and reviewing associated CBCT scans, the clinician is better equipped to assess osteogenic potential of bone AND marrow quality. Question: Can the augmented bone maintain mechanotransduction and can it withstand the occlusal forces over the long term in response to stress and strain? The classification of normal resorption patterns is important (in terms of implant therapy and malocclusion management), because it sets a standard when embarking on complex surgery on what is predictable. 3D imaging of teeth by cross-sectional imaging and volume measurements also helps in the diagnostic planning process. For partially edentulous ridge assessment, Mandelaris et al have published a bone classification system that assesses dentoalveolar bone compartments and separates them in two parts (crestal and radicular), paying particular attention to the crestal bone phenotype in regard to pre-implant regenerative assessments. [90] Some of these phenotypic assessments will be applicable to corticotomy surgery, which is discussed later in this book. Ridge assessment by CBCT has opened up a window of creativity to “think outside the box” in regard to treatment strategy that would not have been possible or appreciated with 2D radiographs. This broadened capability could have a direct bearing on tooth prognosis in conjunction with assessment of bone resorption patterns. CBCT offers lower radiation exposure and cost than medical CT scans. Lower radiation translates to lower resolution. A smaller field of view CBCT scan (i.e., focus field) requires a higher dose. Unfortunately, there is a lack of credentialing and regulation that remains in the profession which sometimes results in a failure of CBCT to have appropriate radiologic oversight.

 asic Summary Questions Regarding CBCT B Ridge Assessment • Where do the teeth need to be in space in order to plan the cases how does that spatial assessment dovetail with existing regional anatomic geometry? • Is this sufficient, or, does the clinician need to augment or otherwise change the anatomy in order to accomplish prosthetic outcome goals? Increasing use of pre-treatment CBCT assessments by the interdisciplinary team should benefit overall treatment outcomes commensurately.

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References 1. Nanci A, Moffatt P.  Section 1: Bones of the oral-dental and craniofacial complex. In: McCauley LK, Somerman MJ, editors. Mineralized tissues in oral and craniofacial science: biological principles and clinical correlates. Wiley-Blackwell; 2012. p. 3–12. 2. ten Cate AR. Embryology of the head, face and oral cavity. In: ten Cate AR, editor. Oral histology development, structure and function. St. Louis, MO: Mosby; 1980. p. 18–46. 3. Chin M. 1. Introduction to surgical design using embryologic processes. Surgical design for dental reconstruction with implants: a new paradigm. Hanover Park, IL: Quintessence Books; 2015. 4. Cho MI, Garant PR. Development and general structure of the periodontium. Periodontol. 2000;2000(24):9–27. 5. ten Cate AR. Development of the periodontium. In: ten Cate AR, editor. Oral histology development, structure and function. St. Louis, MO: Mosby; 1980. p. 218–33. 6. Miller A. Electromyography in hemifacial microsomia. In: Harvold EP, Vargervic K, Chierici G, editors. Treatment of hemifacial microsomia. New York: Alan R. Liss; 1983. 7. Chin M.  Establishing and maintaining osseointegration within the functional matrix. Int J Periodontics Restorative Dent. 2016;36(1):29–37. 8. Chin M. 5. Using developing teeth to generate bone. Surgical design for dental reconstruction with implants: a new paradigm. Hanover Park, IL: Quintessence Books; 2015. 9. Bosson C, Devillard F, Satre V, Dieterich K, Ray PF, Morand B, et  al. Microdeletion del(22)(q12.1) excluding the MN1 gene in a patient with craniofacial anomalies. Am J Med Genet A. 2016;170(2):498–503. 10. Calic A, Peterlin B.  Epigenetics and bruxism: possible role of epigenetics in the etiology of bruxism. Int J Prosthodont. 2015;28(6):594–9. 11. Rot I, Mardesic-Brakus S, Costain WJ, Saraga-Babic M, Kablar B.  Role of skeletal muscle in mandible development. Histol Histopathol. 2014;29(11):1377–94. 12. Seelan RS, Mukhopadhyay P, Pisano MM, Greene RM.  Developmental epigenetics of the murine secondary palate. ILAR J. 2012;53(3–4):240–52. 13. Ejdesjo A, Wentzel P, Eriksson UJ. Influence of maternal metabolism and parental genetics on fetal maldevelopment in diabetic rat pregnancy. Am J Physiol Endocrinol Metab. 2012;302(10): E1198–209. 14. Belfor TR.  Epigenetic orthodontics: facial and airway development. N Y State Dent J. 2010;76(6):18–21. 15. Rangasamy S, D'Mello SR, Narayanan V.  Epigenetics, autism spectrum, and neurodevelopmental disorders. Neurotherapeutics. 2013;10(4):742–56. 16. Kubota T, Miyake K, Hirasawa T. Role of epigenetics in Rett syndrome. Epigenomics. 2013;5(5):583–92. 17. Lalande M, Calciano MA. Molecular epigenetics of Angelman syndrome. Cell Mol Life Sci. 2007;64(7–8):947–60. 18. Herrera BM, Keildson S, Lindgren CM. Genetics and epigenetics of obesity. Maturitas. 2011;69(1):41–9. 19. Grafodatskaya D, Chung B, Szatmari P, Weksberg R.  Autism spectrum disorders and epigenetics. J Am Acad Child Adolesc Psychiatry. 2010;49(8):794–809. 20. Zachariah RM, Rastegar M. Linking epigenetics to human disease and Rett syndrome: the emerging novel and challenging concepts in MeCP2 research. Neural Plast. 2012;2012:415825. 21. Bergersen LH, Sander M, Storm-Mathisen J. What the nose knows, what the eyes see, how we feel, how we learn, how we understand motor acts, why “YY” is essential for ion transport, how epigenetics meet neurobiology in Rett syndrome: seven topics at the 2010 Kavli Prize Symposium on Neuroscience. Neuroscience. 2011;190:1–11.

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Embryologic Development of the Jaws 44. Anand PS, Kamath KP, Shekar BR, Anil S. Relationship of smoking and smokeless tobacco use to tooth loss in a central Indian population. Oral Health Prev Dent. 2012;10(3):243–52. 45. Hanioka T, Ojima M, Tanaka K, Matsuo K, Sato F, Tanaka H. Causal assessment of smoking and tooth loss: a systematic review of observational studies. BMC Public Health. 2011;11:221. 46. Chambrone L, Chambrone D, Lima LA, Chambrone LA. Predictors of tooth loss during long-term periodontal maintenance: a systematic review of observational studies. J Clin Periodontol. 2010;37(7):675–84. 47. Muzzi L, Nieri M, Cattabriga M, Rotundo R, Cairo F, Pini Prato GP.  The potential prognostic value of some periodontal factors for tooth loss: a retrospective multilevel analysis on periodontal patients treated and maintained over 10 years. J Periodontol. 2006;77(12):2084–9. 48. Kerdvongbundit V, Wikesjo UM. Effect of smoking on periodontal health in molar teeth. J Periodontol. 2000;71(3):433–7. 49. Albandar JM, Streckfus CF, Adesanya MR, Winn DM. Cigar, pipe, and cigarette smoking as risk factors for periodontal disease and tooth loss. J Periodontol. 2000;71(12):1874–81. 50. Tonetti MS. Cigarette smoking and periodontal diseases: etiology and management of disease. Ann Periodontol. 1998;3(1):88–101. 51. Burgan SW. The role of tobacco use in periodontal diseases: a literature review. General Dent. 1997;45(5):449–60. quiz 69-70 52. McGuire MK, Nunn ME. Prognosis versus actual outcome. II. The effectiveness of clinical parameters in developing an accurate prognosis. J Periodontol. 1996;67(7):658–65. 53. McGuire MK, Nunn ME. Prognosis versus actual outcome. III. The effectiveness of clinical parameters in accurately predicting tooth survival. J Periodontol. 1996;67(7):666–74. 54. Hart GT, Brown DM, Mincer HH. Tobacco use and dental disease. J Tenn Dent Assoc. 1995;75(2):25–7. 55. Chatzopoulos GS, Doufexi AE, Kalogirou F.  Association of susceptible genotypes to periodontal disease with the clinical outcome and tooth survival after non-surgical periodontal therapy: a systematic review and meta-analysis. Med Oral Patol Oral Cir Bucal. 2016;21(1):e14–29. 56. Geismar K, Enevold C, Sorensen LK, Gyntelberg F, Bendtzen K, Sigurd B, et al. Involvement of interleukin-1 genotypes in the association of coronary heart disease with periodontitis. J Periodontol. 2008;79(12):2322–30. 57. Nibali L, Donos N, Henderson B. Periodontal infectogenomics. J Med Microbiol. 2009;58(Pt 10):1269–74. 58. Martins MD, Jiao Y, Larsson L, Almeida LO, Garaicoa-Pazmino C, Le JM, et al. Epigenetic modifications of histones in periodontal disease. J Dent Res. 2016;95(2):215–22. 59. Kao DW, Fiorellini JP. An interarch alveolar ridge relationship classification. Int J Periodontics Restorative Dent. 2010;30(5):523–9. 60. Cawood JI, Howell RA. A classification of the edentulous jaws. Int J Oral Maxillofac Surg. 1988;17(4):232–6. 61. Cawood JI, Howell RA.  Reconstructive preprosthetic surgery. I.  Anatomical considerations. Int J Oral Maxillofac Surg. 1991;20(2):75–82. 62. Xiao WL, Zhang DZ, Chen XJ, Yuan C, Xue LF.  Osteogenesis effect of guided bone regeneration combined with alveolar cleft grafting: assessment by cone beam computed tomography. Int J Oral Maxillofac Surg. 2016;45(6):683–7. 63. Araujo MG, da Silva JC, de Mendonca AF, Lindhe J. Ridge alterations following grafting of fresh extraction sockets in man. A randomized clinical trial. Clin Oral Implants Res. 2015;26(4):407–12. 64. Zhang W, Shen G, Wang X, Yu H, Fan L.  Evaluation of alveolar bone grafting using limited cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol. 2012;113(4):542–8. 65. Braut V, Bornstein MM, Belser U, Buser D.  Thickness of the anterior maxillary facial bone wall-a retrospective radiographic study using cone beam computed tomography. Int J Periodontics Restorative Dent. 2011;31(2):125–31.

15 66. Hao Y, Zhao W, Wang Y, Yu J, Zou D.  Assessments of jaw bone density at implant sites using 3D cone-beam computed tomography. Eur Rev Med Pharmacol Sci. 2014;18(9):1398–403. 67. Baciut M, Hedesiu M, Bran S, Jacobs R, Nackaerts O, Baciut G. Pre- and postoperative assessment of sinus grafting procedures using cone-beam computed tomography compared with panoramic radiographs. Clin Oral Implants Res. 2013;24(5):512–6. 68. Braut V, Bornstein MM, Lauber R, Buser D. Bone dimensions in the posterior mandible: a retrospective radiographic study using cone beam computed tomography. Part 1: Analysis of dentate sites. Int J Periodontics Restorative Dent. 2012;32(2):175–84. 69. Guerrero ME, Noriega J, Jacobs R. Preoperative implant planning considering alveolar bone grafting needs and complication prediction using panoramic versus CBCT images. Imaging Sci Dent. 2014;44(3):213–20. 70. Braut V, Bornstein MM, Kuchler U, Buser D. Bone dimensions in the posterior mandible: a retrospective radiographic study using cone beam computed tomography. Part 2: Analysis of edentulous sites. Int J Periodontics Restorative Dent. 2014;34(5):639–47. 71. Araujo MG, Silva CO, Misawa M, Sukekava F.  Alveolar socket healing: what can we learn? Periodontol 2000. 2015;68(1):122–34. 72. Mandelaris GA, Lu M.  Extraction socket preservation prior to implant placement. Dent Today. 2015;34(4):78–9. 73. ITI. The SAC Classification in Implant Dentistry. 2016;Available from: http://www.iti.org/The-­SAC-­Classification-­in-­Implant-­Dentistry. 74. Loveless TP, Kilinc Y, Altay MA, Flores-Hidalgo A, Baur DA, Quereshy FA.  Hounsfield unit comparison of grafted versus non-­ grafted extraction sockets. J Oral Sci. 2015;57(3):195–200. 75. Moss ML.  The functional matrix hypothesis revisited. 1. The role of mechanotransduction. Am J Orthod Dentofacial Orthop. 1997;112(1):8–11. 76. Moss ML. The functional matrix hypothesis revisited. 2. The role of an osseous connected cellular network. Am J Orthod Dentofacial Orthop. 1997;112(2):221–6. 77. Moss ML.  The functional matrix hypothesis revisited. 3. The genomic thesis. Am J Orthod Dentofacial Orthop. 1997;112(3):338–42. 78. Moss ML.  The functional matrix hypothesis revisited. 4. The epigenetic antithesis and the resolving synthesis. Am J Orthod Dentofacial Orthop. 1997;112(4):410–7. 79. Harvold EP.  The theoretical basis for the treatment of hemifacial microsomia. In: Harvold EP, Vargervik K, Chierici G, editors. Treatment of hemifacial microsomia. New  York: Alan R.  Liss; 1983. p. 1–137. 80. Aaron JE, Carter DH. Rapid preparation of fresh-frozen undecalcified bone for histological and histochemical analysis. J Histochem Cytochem. 1987 Mar;35(3):361–9. 81. Rosenfeld AL, Mecall RA. Use of prosthesis-generated computed tomographic information for diagnostic and surgical treatment planning. J Esthet Dent. 1998;10(3):132–48. 82. Rosenfeld AL, Mecall RA.  The use of interactive computed tomography to predict the esthetic and functional demands of implant-supported prostheses. Compend Contin Educ Dent. 1996;17(12):1125–8. 30-2 passim; quiz 46 83. Mecall RA, Rosenfeld AL.  Influence of residual ridge resorption patterns on fixture placement and tooth position, Part III: Presurgical assessment of ridge augmentation requirements. Int J Periodontics Restorative Dent. 1996;16(4):322–37. 84. Mecall RA, Rosenfeld AL. The influence of residual ridge resorption patterns on implant fixture placement and tooth position. 2. Presurgical determination of prosthesis type and design. Int J Periodontics Restorative Dent. 1992;12(1):32–51. 85. Mecall RA, Rosenfeld AL.  Influence of residual ridge resorption patterns on implant fixture placement and tooth position. 1. Int J Periodontics Restorative Dent. 1991;11(1):8–23. 86. Rosenfeld AL, Mandelaris GA, Tardieu PB. Prosthetically directed implant placement using computer software to ensure precise place-

16 ment and predictable prosthetic outcomes. Part 1: Diagnostics, imaging, and collaborative accountability. Int J Periodontics Restorative Dent. 2006;26(3):215–21. 87. Rosenfeld AL, Mandelaris GA, Tardieu PB.  Prosthetically directed implant placement using computer software to ensure precise placement and predictable prosthetic outcomes. Part 2: Rapid-­prototype medical modeling and stereolithographic drilling guides requiring bone exposure. Int J Periodontics Restorative Dent. 2006;26(4):347–53. 88. Rosenfeld AL, Mandelaris GA, Tardieu PB.  Prosthetically directed implant placement using computer software to ensure

G. A. Mandelaris precise placement and predictable prosthetic outcomes. Part 3: Stereolithographic drilling guides that do not require bone exposure and the immediate delivery of teeth. Int J Periodontics Restorative Dent. 2006;26(5):493–9. 89. DeGroot BS, Mandelaris GA. Restorative leadership in the era of digital technology. Inside Dentistry. 2016;12(9):2–5. 90. Mandelaris GA, Vence BS, Rosenfeld AL, Forbes DP.  A classification system for crestal and radicular dentoalveolar bone phenotypes. Int J Periodontics Restorative Dent. 2013;33(3): 289–96.

Dental Space Deficiency Syndrome: An Anthropological Perspective Colin Richman

Malocclusion, a ubiquitous problem in the world

C. Richman (*) Department of Periodontics, Augusta University, Augusta, GA, USA Georgia School of Orthodontics, Atlanta, GA, USA © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_2

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Introduction When asking the questions, why do I need to have my wisdom teeth removed, or why are my teeth “crooked” and needing orthodontic therapy (OT), or why do I have gum recession especially following OT, we need to address factors of genetics and anthropology to help us understand the etiology and diagnosis of these conditions, from an interdisciplinary approach. This chapter will address the question “Why don’t our teeth fit our jaws, and what are the Consequences of this Anomaly.” Factors of both genetic and anthropological perspectives of modern mankind’s head and jaws will be reviewed. We will also focus on practical and applicable clinical perspectives relating to new approaches for appropriate treatment and management, both in adult dentitions and adolescents. Therapies for these issues “bigger teeth in smaller jaws” will be addressed through the concepts of Surgically Facilitated Orthodontic Treatment (SFOT), previously known as Pre-orthodontic Periodontal Augmentation (POPA), or Periodontally Accelerated Orthodontic Treatment. Current surveys conducted by the National Institute of Cranio-Facial Health, a sub-section of the National Institute of Health, suggest that there is an incidence of up to 80% malocclusion in the United States of America [1]. This also applies to most other New World countries. Two papers previously published by this author, and partially reproduced with the kind permission of the Aegis publishing Company will help the reader obtain a clearer understanding of the issues at hand [2, 3]. In 2004, the average life expectancy of most Americans was 80  years [1]. Patients are healthier and living longer. They realistically expect to retain their teeth or fixed tooth replacements, both in function and favorable esthetics, for their lifetime. Gingival recession (GR) may increase the risk of premature tooth loss and compromise their ability to meet this goal. Orthodontic crowding, also known as “orthodontic compensation,” is defined as a “discrepancy between tooth sizes and available arch length and/ or tooth positioning, that results in mal-alignment and abnormal contact relationships between teeth.” [4]. Crowding is classified into three categories. Primary (hereditary) crowding is determined genetically and caused by disproportionately sized teeth and available alveolar bone housing. Secondary is an acquired anomaly caused by mesial drifting of the posterior teeth after premature loss of deciduous teeth in the lateral segment, and/ or lingual or distal displacement of the anterior teeth. The etio-pathogenesis of tertiary crowding is still under debate and may be associated with third molar eruption patterns [5–7]. This author pro-

C. Richman

poses a fourth category in which alveolar bone mass is adequate but unable to accommodate the tooth in three planes, resulting in buccal displacement of the tooth. A combination of situations may also exist.

 oncepts Associated with Malocclusion C and Tooth Crowding Both genetic and functional factors [8] seem to be associated with discrepant tooth size and the available alveolar bone phenomenon. From an evolutionary perspective, current evidence suggests the volume of human jawbones (basal and alveolar) is decreasing over time when evaluated in three dimensions [9–12]. Conversely, studies evaluating tooth size in monozygotic and dizygotic twins have suggested that actual tooth morphology and tooth size appear to be predominantly pre-determined by genetics [13, 14]. Thus, the evolving discrepancy between tooth size and available alveolar jawbone, when evaluated in three dimensions, results in a net deficiency of available alveolar bone, unable to accommodate the human dentition. Using cone beam computed tomography (CBCT) imaging, we have demonstrated the phenomenon of tooth size versus alveolar bone discrepancies when viewing alveolar bone anatomy in three dimensions. This phenomenon is particularly evident in sagittal plane sections [2]. Also, it is almost standard practice to remove third molar teeth, in modern and progressive societies, as in most cases they are fully or partially impacted. This suggests a bony volume discrepancy associated with the length of available bone in one or both arches, unable to accommodate the mesiodistal dimensions of 16 teeth (in either or both arches). (“Bigger teeth in Smaller Jaws”) [15, 16] (Image 1). These phenomena are associated with the anthropological concept that over time we changed from prehistoric hunters to gatherers, farmers, and subsequently utilizers of industrialized food production. Because of lack of functionality, especially as we evolved to a humanoid status, and through epigenetic adaptation, the human jaws have been shrinking due to functional disuse [9]. This adaptation continues to this day and studies and surveys suggest that the phenomena will continue unabated into the future. Our foods have become highly processed, and we no longer need to use our jaws for defense and survival, as many mammalian species living in the wild, native and their natural, environment do. Large powerful jaws are no longer needed for human survival from a masticatory or defensive perspective [10]. Breast feeding until weaning has also decreased especially in modern and contemporary societies. The suckling process seems to be important in development of the jaws and oral structures [17, 18].

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Dental Space Deficiency Syndrome: An Anthropological Perspective

Adult, impacted third molar and mal-occlusion

Adult, impacted third molars

Image 1  Impacted teeth Image 2  Profile of prehistoric man versus contemporary man

Primitive man. Larger jaws, smaller skull

The cranium and frontal lobe of the forebrain is increasing in size, at the expense of the human face. The forebrain is the site of humanity especially the prefrontal cortex. Image 2 demonstrates this phenomenon, namely a small cranium and large jaws, versus a large cranium and small jaws. This particularly relates to our prefrontal cortices, the gray matter

Modern man. Larger skull, smaller jaws

of the anterior part of the frontal lobe, which is highly developed in humans and plays a role in the regulation of complex cognitive, emotional, and behavioral functions. Relative to the maxilla and mandible, less functionality over time is resulting in gradual atrophy of these bones, with less capacity to accommodate our genetically determined teeth. This

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occurs through the phenomenon of epigenetic adaptation to functional changes in our bodies over millennia [19, 20]. In addition to the factor of anthropological changes of the human skull and mandible over millennia, the aspect of genetic heterogeneity must be considered. In homogenetic communities (mammals and human), tooth crowding is virtually non-existent. The jaws are usually able to accommodate all teeth in natural function and alignment. However, with greater mobility of mankind over the past few centuries and co-mingling and mating of subjects with different make up, we can also identify a mismatch of tooth size versus available alveolar bone. For simplicity, consider a large football player of Scandinavian descent mating with a small statured Asian gymnast. If the offspring inherits his teeth and her jaws, a significant discrepancy of tooth alignment will probably occur, as a result of the discrepancy between tooth volume and available alveolar bone volume when analysed in three dimension. This is certainly the phenomenon in new world countries, essentially made up of migrants over a few decades.

 ental Space Deficiency Syndrome, (DSDS): D Classifying a New Syndrome for an Evolving Problem A new syndrome for dentistry, DSDS was previously proposed by this author [3]. A syndrome is defined as a group of signs and symptoms that occur together and characterize a particular abnormality or condition [21]. Clinical signs and symptoms of this entity may include one or more of the following conditions: orthodontic tooth crowding; alveolar bone dehiscences and/or fenestrations associated with subsequent gingival recession; tooth impactions especially third molars; rapid resorption of facial alveolar bone plates following premature tooth extractions; dentally oriented sleep disorders; extended orthodontic treatment times and near or long-term relapse following orthodontic therapy. Studies of human inhabitants of metropolitan cities suggest a high incidence of individuals with orthodontic tooth crowding. This includes inadequately erupted third molars [5]. A US Public Health Service Report survey demonstrated that 80% of American children have some degree of malocclusion [1, 22]. Based on this author’s and other researchers’ observations, as well as studies of primitive and contemporary mammalian skulls, it is noted that these problems seldom occur in native human communities, primitive societies or various mammalian animals living in their natural environments and feeding on their native diets. The range of skulls studied in museum collections around the world, are off all shapes and dimension, for example, from small field mice to elephant,

C. Richman

hippopotamus, etc. (data in press) [10]. Typically, these mammals will suckle their offspring until weened. At that time, the young will start eating their natural diets. There seems to be little difference in jaw development between herbivores, carnivores, or omnivores (data in press). These factors are associated with jawbone and particularly alveolar bone development. To verify these concepts, examination of representative preserved human skulls, with appropriate calibrated photographic records where obtained by this author at various museums, including the Smithsonian, the Museum of Natural History in New York City, the Dart Collection in Johannesburg, South Africa, the Natural History Museum of Svalbard and Oslo, together with other smaller collections at various locations. The curators of the various collections generously allowed me to examine specimens in their collections. Specimens ranged from prehistoric humanoid fossils to modern mankind. Image 3 represents samples of large and small mammals alike, in which there is an ideal relationship between these animals living in the wild on a naturally environmentally appropriate diet. Images include the American Black bear, Asian tiger, American Chipmunk, and African Rhesus monkey. Clinical factors relating to DSDS relative to the United States and other metropolitan cities include: 1. Gingival recession occurs in more than 58% of the total population. 2. Tooth impactions, especially third molars, were found in more than 58% of surveyed Australian populations, 73% of surveyed European populations, and in excess of 50% of surveyed American populations [23–25]. 3. Post-orthodontic treatment relapse, in surveyed populations, may be present in more than 80% of patients, possibly many years following treatment completion [22, 26, 27]. 4. Rapid loss of alveolar facial bony plates following tooth extractions is a routine finding, especially the facial bony plate [28, 29]. 5. Dentally related sleep disturbances are substantial and significant in surveyed communities [30]. These phenomena, individually or collectively, seem to be associated with either a discrepancy between available alveolar bone and basal bone volume and tooth volume, (when considered in three dimensions), or are iatrogenically induced due to protracted orthodontic treatment associated with adapting (or ‘forcing’) larger teeth into a smaller alveolar bone capacity. The phenomenon of arch expansion in the crowded dentition is known as decompensation. Image 4 represents an example of DSDS, including gingival recession, prominent facial root eminences, suggesting larger teeth in thinner alveolar bone in the sagittal plane, recession plus crowded teeth, impacted third molars, fenestrations and dehiscences, and a class three basal bone relationship with incompatible jaw sizes.

Dental Space Deficiency Syndrome: An Anthropological Perspective

21 Rhesus monkey

1-Tiger

Black Bear Chipmunk

1-Tiger

5 Rhesus monkey

There is an ideal jaw/tooth relationship between these animals nurtured in the wild on a naturally environmentally appropriate diet plus oral structures.

Image 3  Specimens of large and small mammals

Adult, impacted third molar and mal-occlusion

Adult, impacted third molars

Adult, impacted third molar and mal-occlusion

Deficient Alveolar Bone Note: gingival recession, impacted third molars, deficient alveolar bone, malocclusion. Features of DSDS

Image 4 DSDS

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 ingival Recession—The Clinical Clue G of Alveolar Bone Deficiency Epidemiologic data on 9689 American patients ages 30–99 years demonstrated that more than 11% have one or more tooth surfaces with >2 mm of GR. There were 58% with 1 mm (or more) sites of GR. The rate of GR increased with age (an 80% prevalence of GR in patients with labially positioned teeth, ages 36–86 compared with 40% in patients aged 16–25). GR occurrence is greater in men than women of the same age. The most common location of GR is the facial aspect of canines, followed successively by premolars, incisors, and molars [31–34]. A US Public Health Service report suggests 75% of American children have some degree of malocclusion. Malocclusion rates are higher in developed than in primitive countries (for example, Malocclusion is rare among Australian aborigines and Melanesian islanders) and highest in the US, perhaps because of genetic heterogeneity [35, 36]. Gingival recession (GR) is a frequently observed clinical condition characterized by exposure of tooth cementum, predominantly on the facial surfaces of a tooth or multiple teeth. Lingual GR is observed less frequently. Clinically, GR is always accompanied by alveolar bone dehiscences. A patient may present with more than one affected tooth. The extent of GR usually directly correlates with the extent of the dehiscence observed clinically [37]. Image 5, demonstrates generalized gingival recession post-orthodontic treatment. Tooth #22 is proclined facially, with minimal to no bone on the

C. Richman

facial aspect, RSBI C on the facial and RSBI A on the lingual. (See below for details of the RSBI classification). “A dehiscence may be defined as an alveolar bone deficiency, often exceeding more than half of the root length and resulting in a denuded root surface” [28]. Alternatively, a dehiscence may also be described as the “bursting through the bone of the root as the tooth erupts so that the alveolar supporting bone does not extend to its normal proximity to the CEJ. If during orthodontic tooth movement, the tooth/teeth are translated further labially, treatment might exacerbate the risk of future short- or long-term GR due to the stress being placed onto the associated facial bone. A small dehiscence might be converted to a larger dehiscence, or a tooth with a thin facial plate 2 mm on the midfacial aspect of the involved tooth, and previous periodontal surgical therapy at the involved site (pocket reduction therapy or muco­gingival enhancement) also known as “phenotype conversion.” Following initial patient evaluation, diagnosis, and comprehensive treatment planning, each patient was advised of all periodontal and oral conditions present, and appropriate informed consent was obtained. Indicated regenerative periodontal therapy was provided. After surgical reflection of full thickness periodontal flaps, the facial bony topography of affected teeth was further analyzed clinically, and a photographic record was obtained. All data were tabulated for subsequent analysis and interpretation. Richman observed that each tooth demonstrating >3 mm. facial GR also presented with a root prominence extending beyond the alveolar bony housing (dehiscence). At the time of SFOT surgery, many teeth demonstrated alveolar bone fenestrations or dehiscences, or combinations of both, even though gingival tissue was ideally located at the CEJ. As all patients in this study had previously received detailed oral hygiene instruction with a strong emphasis on gingival margin as well as interdental plaque control prior to the ­treatment appointment, they presented with low gingival and plaque indices at the time of surgical treatment. If indicated appropriate supra-and sub-gingival tooth and root surface debridement was provided through comprehensive scaling and root planing procedures. A RSBI of 1.5–2.00 mm. in the natural dentition is seemingly required to maintain a stable muco-gingival complex and minimize GR. This author recognizes that the preceding concepts are based on clinical observation, and that substantial further research and interpretation are needed to support this hypothesis. Therefore, CBCT three-dimensional analysis as well as clinical photography enables the clinician to observe a consistent relationship between GR and the deficient buccolingual dimensions of the associated alveolar bone at the coronal third of the tooth’s root. Based on these observations, a new radiography-based index, the RSBI (Radiographic Supporting Bone Index) is proposed. It is

based on the volumetric difference between the alveolar bone width, measured at a position 2–3 mm from the CEG (in the buccal-lingual dimension) and the same width of the tooth. The two measurements are then subtracted. The values are obtained from a CBTC study of the patient, and essentially compare the tooth width at this predefined position with the available bone width at the same position. This orientation refers to the sagittal plane only, in other words assessing thicket teeth in thinner bone, facial to lingual. Although published data is lacking relative to an ideal relationship with teeth and alveolar bone, the dental implant literature is replete with evidence that a minimum of 1.5 mm of supporting alveolar bone is essential for long-term gingival health around dental implants [38, 42–44]. We have thus extrapolated this data to natural teeth for maintaining healthy gingival tissues in both the short term as well as the long term. The proposed categories of RSBI are as follows: • Class A: RSBI represents the ideal clinical situation:1.5 mm to 2 mm of available supporting bone on the facial or lingual aspect of each tooth, relative to the pressure side of OTM • Class B: RSBI represents a compromised but potentially stable situation: 0.5 mm of available supporting facial or lingual alveolar bone. • Class C: RSBI represents a high-risk situation for future GR with 2mm of facial bone remaining at #7. (v) Peri-implant bone dimensions measured to ensure long-­ term periimplant bone and soft tissue stability. 2mm of facial bone remaining at #10. (w) Core bone biopsy taken of area where tissue engineering was performed. (x) Core biopsy at 1mm. Histology performed by Dr Peter Schupach (Schupach LTD, Research Lab; Thalwil, Switzerland). (y–zii) 50 micrometer histology sections section. NB= new bone; BR= bone remodeling; OB= Old Bone; G= residual cancellous bone graft particle; CT= connective tissue. Histomorphometry outcome of biopsy sample: New bone= 40.53%; Old bone= 28.68%; Soft tissue= 18.12%; Residual graft particle= 12.67%. (ziii). 3D CBCT Pre-op bone and tooth and implant position. (ziv) Frontal view. Post-op orthodontic tooth position, pre-op bone anatomy (orthodontic tooth movement without dentoalveolar bone augmentation). (zv) Lateral view. Post-op orthodontic tooth position, pre-op bone anatomy (orthodontic tooth movement without dentoalveolar bone augmentation). (zvi) Frontal view. Post-op orthodontic tooth position, post-op SFOT bone anatomy (orthodontic tooth movement complete with dentoalveolar bone augmentation). (zvii) Lateral view. Post-op orthodontic tooth position, post-op SFOT bone anatomy (orthodontic tooth movement complete with dentoalveolar bone augmentation). (zviii) Cross section view of #7. Note bone unionization and augmentation result suggesting a well-defined functional matrix has resulted and ready for implant placement to sustain mechanotransduction long term. Marrow quality is excellent, and vascular potential appears high. (zvix) Cross section view of #10. Note bone unionization and augmentation result suggesting a well-defined functional matrix has resulted and ready for implant placement to sustain mechanotransduction long-term. Marrow quality is excellent, and vascular potential appears high. Supernumerary tooth noted

Bone. The Foundation of a Smile

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The Use of BMP-2 in Conjunction with Implants Importantly, the combined use of dental implants with rhBMP-2 is now receiving attention, as reviewed by Spagnoli and Marx [73]. The authors provide a comprehensive history leading from the early work of Branemark through the evolution of what came to be known as osseointegration, which is defined as a bone-to-metal oxide attachment with a thin, interposed proteoglycan layer. Specifically, titanium reacts with oxygen to form a titanium dioxide (TiO2) layer that produces a pronounced polarization of the implant surface. This polarization, in turn, attracts water-soluble molecules and binds polyvalent cations, which produce a negative charge on the implant surface. Soluble calcium ions (which are positively charged) become attached to the TiO2 surface through electrostatic

interactions, binding proteins, and proteoglycans to the oxide surface of the implant. Success of this interface of the bone-regeneration zone is dependent upon bone vascularity and osteogenic potential, and osteogenesis that happens during osseointegration. BMPs are members of the transforming growth factor-β superfamily of growth factors. Key regulators of cellular growth and differentiation and tissue formation, BMPs exert a variety of effects on mesenchymal stem cells (MSCs) upon exposure to them, as in trauma. BMP-2 plays key roles in vascular proliferation, inducing the actions of BMP-induced vascular endothelial growth factor α (VEGF-α) production in osteoblasts. Perhaps most importantly to the alveolar regenerative process, BMP-2 functions pivotally in the coupling of bone formation and angiogenesis through chemoattraction of neighboring endothelial cells, together with stimulating

Bone. The Foundation of a Smile

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VEGF-α secretion by osteoblasts and endothelial cells. This vascular proliferation in concert with condensations of preosteoblasts during de novo bone formation illustrates the transformative differentiation of MSCs that can survive with low oxygen tensions into osteoblasts that require high oxygen tension, a growth requirement discussed elsewhere in this chapter. Of the 20 known BMPs, BMP-2 (Infuse®, Medtronic) is the only one commercially available for craniofacial bone augmentation. The authors review a number of cases, including the use of BMP-2 for regeneration of a single-tooth implant site, maxillary sinus grafting, the reconstruction of a severely atrophied maxillary alveolar ridge followed by implant placement, and reconstruction of a mandible with a fibular graft [73]. When viewed on CBCT, grafting materials may appear different over time, and may respond variably depending on demands of S/S. Except for those few opportunities, the clinician has to obtain bone cores during implant placement in a constructed or reconstructed site, none will tell the true tale of histology. Thus, a good overarching guideline is to use materials that recap normal embryologic and physiologic events, to support osseointegration or periodontal regenerative therapeutic outcomes that function harmoniously with the body over the long term.

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G. A. Mandelaris 32. Ingber DE.  From cellular mechanotransduction to biologically inspired engineering: 2009 Pritzker Award Lecture, BMES Annual Meeting October 10, 2009. Ann Biomed Eng. 2010;38(3):1148–61. 33. Ingber DE.  Tensegrity-based mechanosensing from macro to micro. Prog Biophys Mol Biol. 2008;97(2-3):163–79. 34. Ingber DE.  Cellular mechanotransduction: putting all the pieces together again. FASEB J. 2006;20(7):811–27. 35. Ingber DE, Tensegrity I.  Cell structure and hierarchical systems biology. J Cell Sci. 2003;116(Pt 7):1157–73. 36. Ingber DE, Tensegrity II.  How structural networks influence cellular information processing networks. J Cell Sci. 2003;116(Pt 8):1397–408. 37. Ingber DE. Tensegrity: the architectural basis of cellular mechanotransduction. Annu Rev Physiol. 1997;59:575–99. 38. Ingber DE, Dike L, Hansen L, Karp S, Liley H, Maniotis A, et al. Cellular tensegrity: exploring how mechanical changes in the cytoskeleton regulate cell growth, migration, and tissue pattern during morphogenesis. Int Rev Cytol. 1994;150:173–224. 39. Ingber DE.  Cellular tensegrity: defining new rules of biological design that govern the cytoskeleton. J Cell Sci. 1993;104(Pt 3):613–27. 40. Ingber DE. Control of capillary growth and differentiation by extracellular matrix. Use of a tensegrity (tensional integrity) mechanism for signal processing. Chest. 1991;99(Suppl. 3):34S–40S. 41. Ingber DE. Mechanical signaling and the cellular response to extracellular matrix in angiogenesis and cardiovascular physiology. Circ Res. 2002;91(10):877–87. 42. Huang C, Ogawa R. Fibroproliferative disorders and their mechanobiology. Connect Tissue Res. 2012;53(3):187–96. 43. Moss ML. The functional matrix hypothesis revisited. 2. The role of an osseous connected cellular network. Am J Orthod Dentofacial Orthop. 1997;112(2):221–6. 44. Moss ML.  The functional matrix hypothesis revisited. 1. The role of mechanotransduction. Am J Orthod Dentofacial Orthop. 1997;112(1):8–11. 45. Braut V, Bornstein MM, Belser U, Buser D. Thickness of the anterior maxillary facial bone wall-a retrospective radiographic study using cone beam computed tomography. Int J Periodont Restorative Dent. 2011;31(2):125–31. 46. Braut V, Bornstein MM, Lauber R, Buser D. Bone dimensions in the posterior mandible: a retrospective radiographic study using cone beam computed tomography. Part 1: Analysis of dentate sites. Int J Periodontics Restorative Dent. 2012;32(2):175–84. 47. Braut V, Bornstein MM, Kuchler U, Buser D. Bone dimensions in the posterior mandible: a retrospective radiographic study using cone beam computed tomography. Part 2: Analysis of edentulous sites. Int J Periodontics Restorative Dent. 2014;34(5):639–47. 48. Loveless TP, Kilinc Y, Altay MA, Flores-Hidalgo A, Baur DA, Quereshy FA.  Hounsfield unit comparison of grafted versus non-­ grafted extraction sockets. J Oral Sci. 2015;57(3):195–200. 49. Mah P, Reeves TE, McDavid WD. Deriving Hounsfield units using grey levels in cone beam computed tomography. Dentomaxillofac Radiol. 2010;39(6):323–35. 50. Sinanoglu A, Kocasarac HD, Noujeim M.  Age estimation by an analysis of spheno-occipital synchondrosis using cone-beam computed tomography. Leg Med (Tokyo). 2016;18:13–9. 51. Demirturk Kocasarac H, Sinanoglu A, Noujeim M, Helvacioglu Yigit D, Baydemir C. Radiologic assessment of third molar tooth and spheno-occipital synchondrosis for age estimation: a multiple regression analysis study. Int J Legal Med. 2016;130(3):799–808. 52. Bazargani F, Feldmann I, Bondemark L. Three-dimensional analysis of effects of rapid maxillary expansion on facial sutures and bones. Angle Orthod. 2013;83(6):1074–82. 53. Silvestrini-Biavati A, Angiero F, Gambino A, Ugolini A.  Do changes in spheno-occipital synchondrosis after rapid maxillary

Bone. The Foundation of a Smile expansion affect the maxillomandibular complex? Eur J Paediatr Dent. 2013;14(1):63–7. 54. Madeline LA, Elster AD. Suture closure in the human chondrocranium: CT assessment. Radiology. 1995;196(3):747–56. 55. Berco M, Rigali PH Jr, Miner RM, DeLuca S, Anderson NK, Will LA. Accuracy and reliability of linear cephalometric measurements from cone-beam computed tomography scans of a dry human skull. Am J Orthod Dentofacial Orthop. 2009;136(1):17 e1–9. discussion-8 56. Celikoglu M, Buyuk SK, Sekerci AE, Ersoz M, Celik S, Sisman Y. Facial soft-tissue thickness in patients affected by bilateral cleft lip and palate: a retrospective cone-beam computed tomography study. Am J Orthod Dentofacial Orthop. 2014;146(5):573–8. 57. Celikoglu M, Ucar FI, Buyuk SK, Celik S, Sekerci AE, Akin M. Evaluation of the mandibular volume and correlating variables in patients affected by unilateral and bilateral cleft lip and palate: a cone-beam computed tomography study. Clin Oral Investig. 2016;20(7):1741–6. 58. Sanders DA, Chandhoke TK, Uribe FA, Rigali PH, Nanda R. Quantification of skeletal asymmetries in normal adolescents: conebeam computed tomography analysis. Prog Orthod. 2014;15(1):26. 59. Melgaco CA, Columbano Neto J, Jurach EM, Nojima Mda C, Nojima LI.  Immediate changes in condylar position after rapid maxillary expansion. Am J Orthod Dentofacial Orthop. 2014;145(6):771–9. 60. Ikeda K, Kawamura A, Ikeda R. Assessment of optimal condylar position in the coronal and axial planes with limited cone-beam computed tomography. J Prosthodont. 2011;20(6):432–8. 61. Tai K, Hotokezaka H, Park JH, Tai H, Miyajima K, Choi M, et  al. Preliminary cone-beam computed tomography study evaluating dental and skeletal changes after treatment with a mandibular Schwarz appliance. Am J Orthod Dentofacial Orthop. 2010;138(3):262e1–e11. discussion-3 62. Dolekoglu S, Fisekcioglu E, Ilguy D, Ilguy M, Bayirli G. Diagnosis of jaw and dentoalveolar fractures in a traumatized patient with cone beam computed tomography. Dent Traumatol. 2010;26(2):200–3. 63. Cevidanes LH, Bailey LJ, Tucker GR Jr, Styner MA, Mol A, Phillips CL, et  al. Superimposition of 3D cone-beam CT models of orthognathic surgery patients. Dentomaxillofac Radiol. 2005;34(6):369–75. 64. Shibazaki-Yorozuya R, Yamada A, Nagata S, Ueda K, Miller AJ, Maki K.  Three-dimensional longitudinal changes in craniofacial growth in untreated hemifacial microsomia patients with cone-­ beam computed tomography. Am J Orthod Dentofacial Orthop. 2014;145(5):579–94. 65. Farronato G, Garagiola U, Carletti V, Cressoni P, Mercatali L, Farronato D.  Change in condylar and mandibular morphology in juvenile idiopathic arthritis: cone beam volumetric imaging. Minerva Stomatol. 2010;59(10):519–34. 66. Garagiola U, Mercatali L, Bellintani C, Fodor A, Farronato G, Lorincz A.  Change in condylar and mandibular morphology in juvenile idiopathic arthritis: cone beam volumetric imaging. Fogorv Sz. 2013;106(1):27–31. 67. Koos B, Gassling V, Bott S, Tzaribachev N, Godt A. Pathological changes in the TMJ and the length of the ramus in patients with

57 confirmed juvenile idiopathic arthritis. J Craniomaxillofac Surg. 2014;42(8):1802–7. 68. Glupker L, Kula K, Parks E, Babler W, Stewart K, Ghoneima A.  Three-dimensional computed tomography analysis of airway volume changes between open and closed jaw positions. Am J Orthod Dentofacial Orthop. 2015;147(4):426–34. 69. Krisjane Z, Urtane I, Krumina G, Bieza A, Zepa K, Rogovska I. Condylar and mandibular morphological criteria in the 2D and 3D MSCT imaging for patients with Class II division 1 subdivision malocclusion. Stomatologija. 2007;9(3):67–71. 70. Esteve-Altava B, Rasskin-Gutman D. Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations. J Anat. 2014;225(3):306–16. 71. Schenk RK, Buser D, Hardwick WR, Dahlin C.  Healing pattern of bone regeneration in membrane-protected defects: a histologic study in the canine mandible. Int J Oral Maxillofac Implants. 1994;9(1):13–29. 72. Jovanovic SA, Schenk RK, Orsini M, Kenney EB.  Supracrestal bone formation around dental implants: an experimental dog study. Int J Oral Maxillofac Implants. 1995;10(1):23–31. 73. Spagnoli DB, Marx RE. Dental implants and the use of rhBMP-2. Dent Clin North Am. 2011;55(4):883–907. 74. Mandelaris GA, Spagnoli DB, Rosenfeld AL, McKee J, Lu M. Tissue engineering for lateral ridge augmentation with recombinant human bone morphogenetic protein 2 combination therapy: a case report. Int J Periodontics Restorative Dent. 2015;35(3):325–33. 75. Fornell J, Johansson LA, Bolin A, Isaksson S, Sennerby L. Flapless, CBCT-guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1-year follow-up. Clin Oral Implants Res 2012;23(1):28-34. 76. Simplant. Latest versions of SIMPLANT.  Dentsply Implants; 2016 [cited 2016 April 2]; Available from: http://www.dentsplyimplants.com/en/Digital-­s olutions/SIMPLANT-­A cademy/ SIMPLANT-­new-­versions. 77. Mandelaris GA, Lu M.  Extraction socket preservation prior to implant placement. Dent Today. 2015;34(4):78–9. 78. Buser D. 20 Years of guided bone regeneration in implant dentistry. 2nd ed. Hanover Park, IL: Quintessence Pub Co; 2009. 79. Rios HF, Lin Z, Oh B, Park CH, Giannobile WV. Cell- and gene-­ based therapeutic strategies for periodontal regenerative medicine. J Periodontol. 2011;82(9):1223–37. 80. Cochran DL, Cobb CM, Bashutski JD, Chun YH, Lin Z, Mandelaris GA, et  al. Emerging regenerative approaches for periodontal reconstruction: a consensus report from the AAP Regeneration Workshop. J Periodontol. 2015;86(Suppl. 2):S153–6. 81. Mandelaris GA.  Tissue engineering for bone reconstruction in implant site development. Lecture. American Academy of Restorative Dentistry (AARD) 85th Annual Meeting; February 28, 2015. Chicago, IL. 82. Rios HF, Bashutski JD, McAllister BS, Murakami S, Cobb CM, Chun YP, et al. Emerging regenerative approaches for periodontal reconstruction: practical applications from the AAP Regeneration Workshop. Clin Adv Periodont. 2015;5(1):40–6.

Part II Patient Assessment, Co-discovery, Diagnosis and Planning the Vision

Co-Discovery: A Pathway to Meaningful and Essential Treatment Brian S. Vence

The Co-Discovery Process We choose technology as a substitute for time. We focus on the chief complaint even when it is tangential to the main concerns of the patient. Doctors focus on the chief complaint because medical schools do not train students in the art of listening! Bernard Lown, M.D. [1]

Co-discovery involves listening during a process that helps patients discover their dental problems and defining essential and meaningful treatment based on their vision of sustainable oral health for a lifetime. Co-discovery began with Bob Barkley, DDS, in the 1970s. Dentistry, based on a personal vision, is wants-based, not needs-based. For example, extraction of an infected tooth would be a need that is necessary to address, thus eliminating the infection. In wants-based dentistry, the patient may choose to extract the tooth to eliminate the infection, graft the extraction site, place an implant, and restore the tooth. When patients select the procedures to restore their oral health, dental treatment transcends elimination of symptoms as a disease [2] to restoring a sense of personal wholeness. Wants-based dentistry involves patients wanting to become more whole and carries some psychological implications. It involves helping to restore a patient’s health that has been lost. The process, however, takes time and involves helping a patient discover the nature of their dental problems and then choose how to treat the problems. Nobody wants to do dental treatment but choose to do treatment when they see the benefits it brings in restoring and maintaining their oral health. The process of helping people choose personal treatments is described in the Internal Flow Chart for the office (Document I) or the Pathway to Essential and Meaningful Treatment (Form 2) for the patient and consists of 10 steps: telephone screening, the initial consultation, diagnostic services, the treatment planning sessions, obtaining a future B. S. Vence (*) Private Practice, Oakbrook Terrace, IL, USA

choice, the action plan, active treatment, preferred outcome, maintenance, and referrals (Document I, Internal Flow Chart). The first step occurs when patients call the office—the first point of contact being a telephone screening (Document I, Section 1—telephone screening/new patient history & Form 1). The purpose of the telephone screening is to determine patients’ desires and to determine early on if the practice could be helpful to them. Essentially, we are trying to find patients who want what we offer. The main goal of the telephone screening is to gain acceptance and initiate a warm welcome with an empathic openness. The best way to discover patients’ wants is to maintain an exploratory curiosity. The quickest way to gain patients’ trust is to accept them for what they want as they go through the co-discovery process. Patients’ wants are fluid and change as they learn more about their condition. Treatment is going to be based on what that patient’s vision is of his or her overall oral health, not the dentist’s vision. However, what a patient wants needs to align with the doctor’s interests. Doctors need to feel that they can be successful in the treatment of the patient desires. The telephone screening is just the start of defining how and why the doctor and patient may work together. After preliminarily identifying the patient’s wants, the next step in the telephone screening is to establish the spirit, nature, and distinctness of the practice. Ultimately, a new patient consultation is scheduled. The receptionist fills out a database that includes the patient’s name, home address, phone number, as well as the patient’s chief complaint. Once those questions are answered, the first appointment is scheduled. During the new patient consultation, we are looking to help people develop a personal vision of how they want to attain and maintain sustainable oral health for a lifetime. The initial consultation creates an environment to explore how the dental team and patient may work together to create a context for their dentistry, which is essential and meaningful treatment. This speaks to the idea of a narrative, which

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involves building a story around what the treatment means to patients and what they want [3]. If patients start to develop a story centered on what they want, the treatment becomes more meaningful. Another task in the initial consultation is to determine the appropriate diagnostic services. Frank Spear, in a workshop called the Practice of Excellence, developed a protocol for typing patients according to diagnostic complexity [4]. Patients are classified as type I, II, III, or IV. Type I patients have no periodontal problems, restorative issues, restorations, or periodontal issues. Type II patients have no occlusal issues, orthodontic issues, or periodontal issues, but have restorative issues involving the need to restore the structural integrity of the tooth, i.e., caries or large restorations. Essentially, type I and type II patients are probably 80% of a typical general dental practice. Type III patients are patients with esthetic wants; patients who may need some esthetic bonding or veneers. Type IV patients are complex restorative cases. These patients have combinations of occlusal issues, periodontal issues, missing teeth and compromise to the size and shape of the teeth due to attrition, erosion, or previous restorations. SFOT patients are type IV patients. For all of these patients, we go through the new patient consultation process to type the patients in order to determine the appropriate diagnostic services for the next phase. In the initial consultation interview, we ask questions to determine the patient’s perception of dentists’ skills and the services they provide (Document I, Section II—New Patient Consultation Questions & Form 3). The first part of the questionnaire is dealing with their current awareness. The doctor or a treatment coordinator may ask the questions. The first questions we ask are, “How may I help you?” as well as, “Do you have any other concerns at this time?” Patients typically will come up with a few concerns. The two most important words during the patient interview: What else? Subsequently, we will ask if there is anything else going on for them. The goal is to create an empathic openness that allows patients to come to us and speak about what is bothering them [5]. The purpose of these questions is to basically determine what is important to the patient. What does the patient believe it means to be a dentist? Ultimately, we are going to form a bridge between the patient’s view of dentistry and the biomedical model the dentist practices. In dental school, I was taught to educate patients. However, patients have their beliefs based on past experiences, something that has developed over a period of time. I feel it is difficult to change a person’s belief in one sitting or even in a few sittings. To be most effective, our goal is to form a bridge between what patients already believe about dentistry and the values, interests, and skills of the practice. Watch your thoughts; they become your words. Watch your words; they become your actions. Watch your actions; they become your habits.

Watch your habits; they become your beliefs. Watch your beliefs; they become your character. Watch your character; it becomes your destiny. –Lao Tzu

We begin to determine the patient’s beliefs of dentistry in the series of questions under the patient’s view of dentistry. Once we can identify some of the problems that patients are concerned about, we can find out what their beliefs are about: how these problems occurred, what they feel needs to be done to correct the problems, what their family and friends feel needs to be done, what they would describe as a satisfactory outcome and treatment, and what their past dental experiences have been like. Following the section on the patient’s view of dentistry, we ask about their medical history, such as, “How do you feel about your health?” We also go through a review of systems or a medical history. I prefer that the treatment coordinator fill out the medical history for the patient because it’s more personal and accurate. In the medical history section, we ask questions such as, “How do you feel about your health? How do you stay healthy? Who is your current physician?” The complete review of systems involves past medical history, past surgical history, medications, and any allergies. We want to know this because it gives a good clue as to who is health-centered in their lifestyle and who is more disease-centered. In general, patients with a disease-centered lifestyle are more needs-based; patients with a health-­ centered lifestyle are more wants-based. Needs, once you fulfill them, you do not necessarily want more. But, health is something that you want more of when you attain it. For example, if you are hungry and you need to eat, once you eat, you are full. You don’t need more food. You are satisfied. If you have a toothache, once you are pain free, you feel good. But, wants-based dentistry is not only the eradication of disease. It involves the restoration of health and enhancement of function. So, once you feel healthy, you want to feel healthier and avoid risk to future problems, which is the basic premise of the whole health-centered practice. It gets into a cultural view of scarcity and abundance. Disease-centered practice really is centered on scarcity, eliminating disease. Patients leave and do not necessarily want to get rid of more disease. They just want to handle disease as it comes up. Being health-centered involves feeling healthy. And, as you feel healthy, you want more health. A good example of that is just simply flossing your teeth. Once you get used to brushing your teeth every morning, you do it every day; and though you may not really feel like flossing, once you do it regularly, you do it every day because it feels healthy. The next set of questions involves asking patients about the motivation behind their visit. The questions we ask are, “What prompted you to come in at this time? If you could change anything in your mouth, what would you like to have

Co-Discovery: A Pathway to Meaningful and Essential Treatment

done? Are there other concerns you have that may prevent you from having treatment? In what timeframe do you want to complete your dental treatment?” We want to ensure that we address patients’ concerns in a timely fashion. We do not want to drag them into a long, drawn out co-discovery process if their main concern is a broken cusp on the mandibular left first molar, tooth #19, when really they just want to get the tooth restored. First, we treat emergency needs or needs perceived by the patient as an emergency. We handle that first before going into a more extended conversation around what they want for their oral health. With co-discovery, the patient needs to be able to envision a better future. They cannot do that when they have a perceived emergency. Bob Barkley gave a talk back in the 1970s about dentists having a slum mentality. The slum mentality was based on a study of a group of people from the ghetto—those who broke out of the ghetto and those who stayed. What he meant related to a study by Dr. Singer, a Harvard sociologist, completed on people raised in slums. The study looked at children from slums and followed them into adulthood. The biggest indicator to predict if someone would break out of the ghetto was not intelligence, athletic ability or popularity—but rather imagination. If a child could picture himself not living in the slum—if he could imagine living differently, a preferred future—then he could break out of the slum [6]. We would like patients to talk about the future and imagine something different, too, than what they have right now, which essentially is what we discussed about sustaining oral health for a lifetime. We want to help patients attain sustainable oral health. The way we approach this is by addressing their dental history, present condition, and future goals. We also discuss such things as their fear of fees, timeframe, busy lifestyle, and lack of time to come into the practice repeatedly. If that is the case, you are not going to get anywhere with patients as far as extensive treatment. If they want to, patients will make the time to find out about their oral health and make choices about their oral health. One of the last questions in the patient consultation comes from Avrom King’s work back in the 1980s and has to do with a discrimination-life theme. We ask patients what they do in their free time. King found that people who have at least three activities that they identify in their free time are more likely to have this discrimination-­life theme and want fine dentistry. The last two questions in the patient consultation are centered on patients’ expectations. Typically when asked about expectations patients will say, “Do a good job.” We would like for patients to tell us what the meaning of “a good job” is for them. It is essential for interviewers to avoid projecting their own personal meaning of “a good job” onto the patient. The question about doctors’ expectations opens up the opportunity for us to talk about the nature of the service that

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we provide. We want to be transparent about fees, time commitment, and quality of treatment. We are a fee-for-service practice, which provides personalized dentistry. The practice is based on patients’ personal vision for their oral health. The goal is to lower a patient’s risk for future oral health problems and has sustainable oral health for a lifetime. In order that finances are not an obstacle to treatment, fees and financial arrangements are discussed prior to treatment once the action plan is developed. The co-­ discovery process, the diagnostic treatment planning, and execution of care for SFOT necessitate more time, a greater skill set and commensurate fees. Regarding insurance and financial policies, we are a fee-­ for-­service dental practice. We expect payment at the time of service. We do not accept direct payment from the insurance company because we are not the insurance company’s client. With regard to appointment scheduling, we have longer appointments. We do not double-book to protect ourselves from no-shows or last-minute cancellations. So, we ask patients to take their appointment commitment seriously as we take their dental treatment seriously. After we have completed the initial consultation and have typed the patient as I, II, III, or IV, we then will go into the third part of the essential and meaningful treatment, which involves diagnostic services. At this point, we conduct what is called a clinical evaluation that involves the new patient exam: examining the joints, muscles, occlusion, structural integrity of each tooth, restoration of each tooth, the periodontal evaluation, along with oral cancer screening [7] (Document I, Section III— Diagnostic Services & Forms 4, 5, & 6). We also obtain full-mouth radiographs and diagnostic photographs. I find diagnostic photographs more important in determining oral health problems than I do using full-mouth radiographs. The reason it is more important is that I am able to identify more problems in the photographs than in the clinical exam. But, more importantly, the patient is able to see the issues. If there are signs of a pathologic occlusion, such as attrition, erosion, abfraction, non-carious cervical lesion, and crenation on the lateral border of the tongue, we will ask for a records appointment. Our records appointment consists of gathering a face-bow, impressions of the maxillary and mandibular arches, interocclusal record in a fully-seated condylar position (FSCP), and a protrusive record. The impressions are poured up, and casts are fabricated and mounted on a semi-adjustable articulator in a FSCP. FSCP is an orthopedic position that is based on the temporomandibular joint, while maximum intercuspation (MI) is a tooth position [8]. The purpose of mounting casts on a semi-­ adjustable articulator is to evaluate the condition and position of the teeth, the joints, the occlusion, and do a functional analysis. In order to do a functional analysis, I use the SAM articulator with the mandibular positioning index (MPI) that

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demonstrates the condylar movement as the patient goes from a fully-seated condylar position to MI and possible stretching of the capsule of the joint  with a lateral movement. In addition, we ask for a high-resolution pulse oximeter screening. Pathologic occlusion is sometimes an erroneous term. It is derived from when dentists believed the occlusion was causing the pathological signs. Now, these pathologic signs are often related to sleep-disordered breathing, GERD or both [9–11]. We will screen with the HRPO to see if sleep-­ disordered breathing (SDB) is an etiological factor. A referral to an ENT physician is made if the screening is positive for an accurate diagnosis. Once we gather the diagnostic data, the next step is to discover the problems together with the patient (Document I, Section IV—Treatment Planning Session & Form 7). I don’t typically look at the diagnostic information until I have it in front of the patient, and I am seeing it for the first time. I look at the data esthetically, functionally, structurally, and biologically. Together, we begin by evaluating the photographic series: full-face, close-up smile, retracted frontal view with the teeth together and apart, lateral views of the teeth together and apart, and maxillary and mandibular occlusal images. Through the images, we evaluate esthetics (facial and dental), function, structural integrity of the teeth, and biologic health. We identify the dental problems with the patients, and we integrate systemic findings. Before I reveal what I’m seeing, I ask the patients what they are seeing in the full-face photo that they like or dislike. I will ask, “What are you seeing in the close-up smile photo that you like or don’t like?” We then examine the retracted view with the teeth together to get an idea of the occlusal plane, gingival levels and these types of things. The lateral view of the teeth together and apart shows us the intercuspation and wear pattern. This is where we look for signs of pathologic occlusion. The maxillary and mandibular occlusal views help us evaluate the arrangement of the teeth, arch form, and structural integrity of the teeth. The photographs of the shade tabs help evaluate the current shade of their teeth. After we’ve gone through the images and identified the problems esthetically, functionally, structurally, biologically,  and systemically we will integrate the dental radiographs. We can see most of the biological issues coming from the periodontal examination with the probing depths and bleeding. The full-mouth X-rays and a cone beam will divulge endodontic issues  and  other biologic issues. This also will allow us a better idea about the biology of the patient. Another important aspect for the patient’s biology is the hi-res pulse oximeter screening. SDB has a major impact on a patient’s oral health, but even a larger impact on the patient’s overall well-being or systemic health. If patients

B. S. Vence

have signs of an airway problem, they will be referred to an ear, nose, and throat doctor for further evaluation and a possible endoscopy and sleep study. Patients have an uncanny ability to identify every problem in their mouth. We don’t tell patients what problems we are seeing. We let them identify the problems first. If we have to jump in because they did not identify a particular problem, we will ask, “What do you think of this?” and point out the problem. We are amazed how often patients are able to identify their problem immediately, without any input. What this allows is for the patient to own the problem. Once the patient identifies the problem, we do what Frank Spear refers to as non-judgmental reporting. This is what we’re seeing, this is what we think is ideal or what we consider to be ideal, this is what we think will happen if we do nothing about this issue. Then, we ask the patients, “What would you like to do?” It’s even better if the patient asks, “What can I do about this?” before we even have to ask them what they want to do. We help them determine how they want to reduce their risk of future dental problems and have sustainable oral health for a lifetime. We want patients to identify how they want their teeth to appear as far as facial esthetics, and how we may optimize their function so their dental treatment is enduring. Nothing contributes more to the longevity of restoration or the dentition than a carefully corrected occlusion in which the forces are minimized. When occlusal forces are unable to be minimized  through tooth contacts, they are distributed over as many teeth as possible. The late Dr. Morton Amsterdam, a renowned educator and clinician from the University of Pennsylvania, said, “There are many solutions to dental problems, but only one correct diagnosis.” Once we’ve identified the problems patients want to address with their oral condition, we need to help them determine what treatment they prefer. This is based on what patients want to do to lower the risk of future dental problems and what they want to invest in terms of time, money, energy, and outcome. We use a document called the risk assessment developed by John Kois (Form 08). It has a problem list on one column for the five areas we evaluated: esthetics, function, structural integrity, biologic health—along with systemic health and patients’ preferences. We want to lower patients’ risk so as not to jeopardize sustainable oral health for a lifetime. We will put the problems on one side and then we will identify whether it is high, medium, or low risk, and decide what treatment would be indicated to reduce the risk. I find it most effective for patients to identify the problems with me and then determine treatment based on their preference to lower risk of future dental problems. In other words,  what treatment would prefer me to provide for them? I consider treatment mindfully  chosen by the patient based on their preferences to be ideal treatment for the patient.

Co-Discovery: A Pathway to Meaningful and Essential Treatment

An example of this could be someone in the structural integrity part of this risk assessment template. They may have an issue with tooth decay and have a large cavity under an old amalgam restoration. If they let it remain as is and it keeps getting bigger, they are going to get into a biologic health problem—when the decay reaches the pulp. But, if a patient has financial limitations and won’t have any disposable income for a couple of years, they may choose to just remove the decay and restore the tooth with an amalgam restoration, just to stop the decay process. However, a large amalgam restoration will not restore the structural integrity of the tooth to prevent it from fracturing over time. The treatment that would lower the risk further would be an onlay. Providing an onlay would solve the decay problem and restore the structural integrity of the tooth. However, this is more costly. The “ideal treatment” for the person who has financial constraints may be to remove the decay, place an amalgam, and wait until more funds are available to restore the tooth with an onlay. Phasing treatment allows patients to customize their treatment plan to lower their risk, but to do it in a way they can afford. The treatment planning sessions identify all of the oral health problems, develop a diagnosis and a strategy for patients to address the issues in order to reduce the risk. The next visit involves obtaining a future choice, which encompasses nailing down what treatment patients are going to do (Document I, Section V—Obtaining a Future Choice). This is about what we have discovered as far as what the essential meaning is to that treatment; bring that together along with deciding what their preferred future is going to be and how they want to resolve the diagnostic findings. The goal is to help connect the emerging meaning derived from the patient consultation with the doctors’ techniques necessary to attain the preferred future of oral health with what that patient desires and help them understand what their choice means in terms of time, money, energy, and outcome. The goal is sustainable oral health for a lifetime. For example, say that you and your wife decide to put in a new kitchen in your home. You may have received some money from your parents or maybe from grandparents who passed away and left you $30,000, and you think that is going to provide enough to get the kitchen of your dreams. So, you talk with your wife. You call the contractor and tell him you want a new kitchen. Maybe impulsively, you say, “First of all, we just want you to know that money is no object. We have the bill covered. This really is our dream to have this great kitchen. Some requirements might be a Sub-­ Zero refrigerator, a Viking stove, an island with granite countertops, and even move a wall in the kitchen to make it a little bigger.” The contractor hears that money is no problem. The contractor says, “I got it. I will be back in a little bit and come up with the kitchen of your dreams.” He comes up with the kitchen of his dreams and you actually love the example.

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You think he did exactly what you wanted until he tells you that the total cost is going to be $150,000. At that point, you feel a little bamboozled, and that maybe you are being taken advantage of. And so, you decide that you are going to find another option. In dentistry, I like to use this future of choice stage so patients understand what they are choosing in terms of treatment and fees. If someone is going to be doing a reconstruction and they have a lot of attrition and erosion of their teeth, they  may  have to do orthodontics, SFOT and restore the missing tooth structure. This will involve a lot of treatment planning. We are going to do an orthodontic setup and diagnostic wax-up. Once orthodontics has regained the lost space to restore teeth to their proper dimensions, we have to do transitional restorations and a full-mouth reconstruction at the end. This involves a lot of treatment. And, because of the clinical time, can get quite expensive. In this type of case, I use real-life analogies to discuss the cost of such expensive treatment—much like buying an M-Series BMW for $125,000. For example, if patients are contemplating removing their teeth and doing fixed dentures and implants, then I want them to know that it’s going to be more like buying a Lexus, a really nice Lexus for $60,000. I use these analogies before we provide and make up an action plan (Document I, Section VI—Action Plan). We want patients to not be surprised by the fees associated with the action plan. The action plan is going to be a word document that itemizes out, step by step, each phase of treatment for that particular patient. It will also include a timeline and a financial summary. For complex cases, (see sample action plan) patients need to go through the diagnostic steps, along with the interdisciplinary consultations, an orthodontic setup and diagnostic wax-up. Then, the patient may have pre-SFOT restorative care that may need to be done and then pre-SFOT orthodontics, SFOT surgery, the post-SOFT surgery orthodontics after space is created, transitional restorations will be placed based on the orthodontic setup and diagnostic wax-up. Then, that would move into finishing the orthodontics and the steps as far as prepping and provisionalizing the teeth, getting into a CAD/CAM provisional that replicates the final restoration. We go through trial therapy to work out esthetics, function, phonetics, neuromuscular, parafunctional, and dental envelope of functions along with soft tissue grooming for final impressions. Final impressions are fabricated along with mounted casts of the diagnostic provisionals after trial therapy. Photographs are made. The final shape of the diagnostic provisional is scanned into a CAD file to be utilized to fabricate the definitive restoration. After trial therapy in the provisional, necessary modifications are incorporated into the shape of the definitive restoration. The restorations are then colorized by the ceramist.

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All of these phases for a complex SFOT case would also have a timeline that would show the sequencing of these phases (see timeline example). It wouldn’t necessarily show the exact time between the sequencing, but it could if we were fairly clear about that. However, at least it gives us an idea of where they are on this timeline and then they can go back and refer to the Action Plan, which elaborates on each phase of treatment and associated fees. Once we have developed the action plan, we are going to write up the whole action plan with the phases and sequencing of treatment including other specialists. The next step is active treatment. We feel it is important for the patient to be relaxed, focused and remain calm as we treat them (Document I, Section VII—Active Treatment). We reserve ample time on the schedule for treatment. So, it is important for patients to be on time and let us know their availability to avoid double-booking appointments. We do this to protect ourselves from no-shows. It also is important for us to avoid, if possible, last-minute cancellations. Once we have gone through the active treatment steps, our goal is to reach that place where we see the preferred outcome—a stable, healthy, esthetic mouth, and sustainable oral health for a lifetime (Document I, Section VIII— Preferred Outcome). In the maintenance phase (Document I, Section IX— Maintenance), we want to find out if patients are either in an occlusal splint or night guard to protect their restorations, or if they have a mandibular advancing device that is from attrition and erosion due to airway issues. During this stage, there is a continuing care program between our office and the periodontist’s office, usually alternating. We want to stay in contact with the periodontist so we can observe what is happening with any occlusal issues. We appreciate referrals of people that our patients feel would benefit from our services (Document I, Section X—Referrals). The co-discovery process develops a narrative around what is essential and meaningful treatment to that particular

B. S. Vence

patient. The narrative provides motivation for the patient and purpose for the dentist in carrying out these technical steps. This process helps unlock the meaning behind a patient’s oral health. A thorough, ongoing consultation helps develop a shared purpose between the patient’s sense of essential and meaningful treatment and the doctor’s professional interests. The shared purpose essentially becomes the action plan to satisfy the patient.

References 1. Lown B.  The lost art of healing. Boston: Houghton Mifflin Company; 1996. 2. Kleinman A.  The illness narratives: suffering, healing, and the human condition. New York: Basic Books; 1988. p. 10. 3. Mattingly C.  Healing dramas and clinical plots. Cambridge: Cambridge University Press; 1998. p. 8. 4. Spear F. The practice of excellence. Chicago Workshop July 8–10; 1999. 5. Lipkin M, Putnam S, Lazarre A. The medical interview. New York: Springer; 1995. p. 65–83. 6. King A. Choosing to choose. Phoenix, AZ: Dharma; 1998. p. 137. 7. Dawson P.  Functional occlusion: from TMJ to smile design. Maryland Heights: Mosby; 2006. p. 3. 8. McKee J. Comparing condylar positions achieved through bimanual manipulation to condylar positions achieved through masticatory muscle contraction against an anterior deprogrammer: a pilot study. J Prosthet Dent. 2005;94:389–93. 9. Adachi H, Mikami A, Kumano-go T, Suganuma N, Matsumoto H, Shigedo Y, Sugita Y, Takeda M.  Clinical significance of pulse rate rise during sleep as a screening marker for the assessment of sleep fragmentation in sleep-disordered breathing. Sleep Med. 2003;4:536–42. 10. Kato T, Rompre P, Montplaisir JY, Sessle BJ, Lavigne GJ.  Sleep bruxism: an oromotor activity secondary to micro-arousal. J Dent Res. 2001;80:1940. 11. Demeter P, Visy KV.  Magyar P “Correlation between severity of endoscopic findings and apnea-hypoapnea index in patients with gastroesophageal reflux disease and obstructive sleep apnea”. World J Gastroenterol. 2005;11(6):839–41.

Patient Assessment Brian S. Vence

• • • • • •

Facially Generated Treatment Planning. CORE Global Diagnostic Treatment Planning. Dentofacial Analysis. Digital Smile Design (DSD). Joint Based Malocclusion. Airway Considerations.

 etermining the Position of the Central D Incisors for Esthetics, Function, and Airway Though the ideal position of the central incisor has not been clearly identified in dental literature for esthetics, function, and airway, several practitioners have devised systems to evaluate the face. The three systems are facially generated treatment planning, CORE esthetic evaluation, and Digital Smile Design (DSD). Together, these systems help determine the ideal position of the central incisor, though they are not perfect. However, when used in combination, a reasonable position may be determined with respect to facial esthetics, function, and airway. The treatment planning template (Temp. 1) may be used to identify dental issues of concern and recorded into a treatment planning template. (TREATMENT PLAN…N- template.doc).

from biologic health to esthetics. As a result, esthetics is the outcome of a well-executed treatment plan.

Esthetics The esthetic component of facially generated treatment planning consists of tooth position, gingival display, arrangement, contour, and color. The five esthetic keys are midline, incisal edge position, incisal plane to occlusal plane, incisal plane to smile line, and gingival levels.

Facial and Dental Esthetics Patients are evaluated for facial and dental esthetics (Figs. 1 and 2). The facial esthetic analysis begins with valuing the

Facially Generated Treatment Planning Facially generated treatment planning—a system that begins with the evaluation of facial and anterior dental esthetics— has been described in the literature by Spear et  al. [1] Treatment planning components consist of esthetics, function, structural integrity, and biologic health. The goal is to develop a treatment plan that addresses everything from esthetics to biologic health, and then execute that treatment B. S. Vence (*) Private Practice, Oakbrook Terrace, IL, USA

Fig. 1  Full face pre-op frontal view

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_5

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Fig. 3  Facial thirds Fig. 2  Profile view

patient’s facial height. The upper, middle, and lower thirds of the face should be equal in proportion [2] (Fig. 3). Restorative dentistry has the greatest influence over the lower third of the face by altering the occlusal vertical dimension [3]. With facially generated treatment planning, the dental midline is ideally on the facial midline or philtrum of the upper lip [4] (Fig. 4). While having the dental midline coincide with the facial midline is ideal, it is unnecessary for optimum esthetics [5]. The incisal edge position and incisal plane need to be identified. Dentists often are taught that the dental midline and facial midline are coincident and should form a perpendicular line with the occlusal and incisal plane. Furthermore, the interpupillary line, occlusal plane/incisal plane, and commissural line are taught to be parallel and level with the horizon [2] (Fig. 5). However, this is rarely the case and can lead to a denture appearance if followed rigorously. Patients do not have symmetrical faces. The first step to achieving natural esthetics is harmony without symmetry and identifying facial asymmetry. In a frontal view, people have asymmetric faces with a long side and a short side as measured from the tragus of the ear to the soft tissue pogonion of the chin (Fig. 6). Except in cases of surgery or trauma, the dorsum of the nose tends to favor the short side of the face, as does the dental midline. The dental midline is on or runs parallel with

Fig. 4  Incisal edge position, facial, and dental midlines

Patient Assessment

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Fig. 5  Interpupillary line, commissure line, and facial long axis Fig. 7  Lines depicting dorsum of nose, facial, and dental midlines favoring the short side of the face

the facial arc, and the occlusal plane is canted to make it perpendicular to the midline on the facial arc [6] (Fig. 7).

Tooth Position

Fig. 6  Long side of face and facial arc

Incisal edge position, position of the central incisor, is determined in three views: frontal, sagittal, and the 12 o’clock view. The frontal view is determined in the repose lip ­position and active smile (Figs.  8 and 9). Incisal edge display is greater in younger patients and less in older patients. Incisal edge display in repose is 2–4 mm with optimal facial esthetics [7]. In the sagittal view, the facial plane of the central incisor is perpendicular to the occlusal plane. The incisal plane and occlusal plane are on the same level (Fig. 10). The maxillary lip support is more difficult to determine. In a 12 o’clock view down the patient’s long axis of the face, the incisors follow the wet/dry line or vermillion of the lower lip [8] (Fig. 11). The facial plane of the central incisor is perpendicular, dropped down from the esthetic plane at ANS in a cephalometric radiograph [9] (Fig.  12). These three views give reasonable parameters for the anterior projection of the central incisors. Gingival display, tooth display, lip length, lip mobility, gingival levels, papillary levels, and tooth length all are related in smile esthetics (Fig.  13). Average lip length for females is

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Fig. 8  Repose demonstrating 5 mm of incisal display

B. S. Vence

Fig. 11  12 o’clock view showing the relationship of the incisal edge projection to the vermillion line of the lip

Fig. 9  Active smile showing incisal position, gingival display, arrangement, contour, and color Fig. 12  Esthetic plane and relationship of central incisors to a 900 reference line dropped from the anterior nasal spine

Fig. 10  Lateral view showing the relationship of central incisor facial plane to incisal plane to occlusal plane

Fig. 13  Gingival display

Patient Assessment

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18–22 mm and 20–24 mm for males. Average lip mobility is 6–8 mm [10]. The average length of a central incisor is a range of 8.0–12.0 mm. The anterior teeth have an intrinsic proportion, width/length, that exhibits a range of values and are related to dental esthetics [11] (Tables 1 and 2; Fig. 14). Excessive gingival displays have seven causes: short upper lip, hyper-mobile lip, vertical maxillary excess, anterior over-eruption, compensatory eruption due to attrition or erosion, altered passive eruption, and altered active eruption (See Table 3). The first four causes for an excessive gingival display possess a normal tooth length; the last three possess short tooth lengths. Compensatory eruption due to wear has a thick incisal edge. The CEJ is identifiable on all except altered active eruption due to the crestal bone being less than 2.0 mm from the CEJ [12]. Anterior over-eruption and compensatory eruption due to wear have uneven gingival levels. Vertical maxillary excess and a short upper lip have an excessive tooth display in repose. Most patients have a combination of issues, which can make diagnosis challenging. Teeth that undergo attrition and erosion migrate, leaving irregular gingival levels and space appropriation issues [1]. The gingival scallop and papillary tips are level when the teeth and roots are aligned (Fig. 15).

Table 1 Average tooth length and width

Table 2 Average proportions

intrinsic

Fig. 14  Intrinsic proportions of the maxillary incisors

Table 3  Seven causes for an excessive gingival display Short upper lip Hyper-mobile lip Vertical maxillary excess Anterior over-eruption Compensatory eruption due to attrition or erosion Altered passive eruption Altered active eruption

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Arrangement Teeth arrangement is related to arch form. Malposition and crowding of teeth may be related to genetics, or epigenetics such as airway issues due to tongue posture with inadequate maxillary arch development [13]. Regardless of the etiology, when there is crowding or narrow tooth forms from previous restorative dentistry the length of the arch form is shorter than the ideal tooth widths added together. The intrinsic proportions of the teeth will be abnormal. Furthermore, crowded teeth or restored teeth that appear too narrow will have inadequate inter-radicular space for root proximity (Fig.  16). Inadequate inter-radicular root space is a sign of the need to expand the perimeter of the arch form with orthodontics.

Contour Tooth contour is a problem when there is inadequate tooth morphology and dimension. Teeth lose form and size for a

B. S. Vence

variety of reasons including attrition, erosion, faulty restoration, faulty genetic instruction, and iatrogenic causes. The tooth contour problem shows up in restorative dentistry as a space appropriation issue (Fig. 17). Teeth migrate to remain in contact with the opposing arch and adjacent teeth. When space is lost the tooth can’t be restored to its correct size and shape without orthodontic intervention to regain the space. Diminished tooth size affects esthetics, occlusion, and oral cavity volume. The smaller the ratio of tongue volume to oral cavity volume the less likely the patient is to have sleep-­ disordered breathing [14].

Color Color must be perceived, not merely seen (Fig. 18). Color is made up of hue, chroma, and value. Hue is determined by the wavelength of the stimulus or the wavelength of light. The wavelength of white light from shortest to longest is violet, blue, green, yellow, orange, and red. The dominant wavelengths of reflected light by teeth are in the yellow-orange range. Chroma is the saturation of hue. As chroma increases value decreases. Value is the amount of light returned to the eye of the observer. We are only able to see the true color of

Fig. 15  Gingival levels and papillary levels of the maxillary arch

Fig. 17  Contour of anterior teeth

Fig. 16  Crowded dentition and insufficient space with root proximity

Fig. 18  Color of anterior teeth consists of hue, chroma, and value

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Patient Assessment

an object if the source of light has all the wavelengths of light. The quality of light is measured in degrees Kelvin and relates to the wavelengths in the stimulus. White light has all the wavelengths of light and is around 5200 to 5500 degrees Kelvin. Quantity of light is measured in foot candles. Value is the amount of light returned to the eye of the observer. If all the white light is absorbed, we see black. If all white light is returned, we see white. Teeth have natural characteristics, surface texture, and internal properties that interact with white light to create the color we perceive. Teeth are translucent, and white light is transmitted, reflected, and refracted. Shadows created by the lips complicate what we see. Patients’ think that they want white teeth, but they also want an inherent sense of realism. This means semi-translucent, not opaque. The challenge for the ceramist is to move light like it moves through teeth. However, ceramic is a completely different medium than teeth. Ceramic is made up of particles suspended in a glass. Light is the stimulus, the eye the receptor and the brain the interpreter [15].

CORE Esthetic Values

Facial Height Facial height compares the mid-face to the lower third of the face. This ratio ideally is 1:1. Mid-face is measured from glabella to subnasale; the lower third of the face is measured from subnasale to menton in repose [3].

Lip Length Lip length is measured from subnasale to stomion superioris. The average lip length for a female is 18–22 mm. The average lip length for a male is 20–24 mm.

Lip Mobility Lip mobility is determined by measuring the distance from the incisal edge of the central incisor to stomion superioris in an active smile. This measurement is subtracted from the meaTable 4  CORE esthetic values

Rouse and Robins developed the CORE esthetic values. CORE stands for Comprehensive Oral Rehabilitation and Esthetic dentistry. This system analyzes numerical values that relate the mid-face to the lower third of the face, the lip length and lip mobility to the tooth display and gingival display, and tooth length to the CEJ. The CORE evaluation answers five questions: facial height? lip length? lip mobility? gingival line? tooth length? CEJ? (See Table 4 and Fig. 19).

Fig. 19  Core esthetic evaluation

Facial height? Lip length? Lip mobility? Gingival level? Tooth length? CEJ? Notes:

CORE values 1:1 20–22 mm Female 22–24 mm Male 6–8 mm Straight 10 mm Yes

Case values

Abnormal √

Core Esthetic Evaluation Core Values

Case Values

Abnormal

Measurements

Facial Height

1:1

71/74mm

X

Mid-face/ lower face

Lip Length

20-24mm

21.0mm

Lip Mobility

6-8mm

7.0mm

Gingival Levels

Straight

Irregular

X

Straight

Tooth Length

10.0mm

9.9mm

X

Incisal to FGM

CEJ

Yes

yes #5-12

Female 20-22mm Male 22-24mm Repose to tooth display

CEJ

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surement of the incisal edge display in repose. If there is difficulty with the patient generating a natural active smile, have them say “E” as they smile. This is an “E” smile. Repose is the relaxed lip position. Repose is found by having the patient say “Emma” with the mandible relaxed. When the maxillary lip covers the incisal edge, the incisors do not display in repose. Measure how far under the lip the incisal edge is with a periodontal probe and record this as a negative number [10].

Gingival Levels The gingival scallop and papillary tips are approximately level across the maxillary incisors [1]. The gingival scallop is most accentuated around the maxillary incisors and progressively flattens out toward the posterior teeth. The maxillary gingival levels parallel the maxillary occlusal plane.

Tooth Length The central incisor tooth length averages are reported as 10.4  mm–11.2  mm [16]. In fact, there is a wide range of tooth lengths for centrals, laterals, and canines [11].

CEJ The cementoenamel junction is only difficult to locate when it is positioned subgingivally. The CEJ is located by using a sharp dental probe. Placing the tip apically in the sulcus and dragging it coronally, the CEJ is discovered when an edge is felt. Altered active eruption is the cause of being unable to locate the CEJ. Altered active eruption is suspected when the patient presents with short clinical crowns, particularly without attrition [17].

Dentofacial Analysis Facially generated treatment planning and CORE global diagnostic treatment planning, functional analysis, structural integrity of the tooth, and biologic evaluations enable dentists to determine a comprehensive list of a patient’s stomatognathic issues. A problem list for a patient’s esthetic issues can be developed. Particular relationships and measurements are identified and recorded. An objective analysis is developed to determine how far a patient’s esthetic parameters deviate from ideal. A patient may choose the treatment modalities necessary to move closer to ideal esthetic parameters or accept the compromises of non-treatment.

B. S. Vence

Digital Smile Design (DSD) Digital smile design is a method of working out the esthetic data that has been collected for any given patient during an esthetic evaluation and developing a template to work out a plan to reach an ideal facial esthetic outcome [8]. In order to develop a smile design that is spatially relevant, a photo of the patient’s face, an active smile, a retracted lip photo, occlusal, and a 12 o’clock view of the patient’s smile are utilized (Fig.  20). The facial, smile, and retracted photos need a consistent camera angle so the images may be superimposed accurately during the design process. The facial photo is placed in Keynote or PowerPoint to manipulate the images for Digital Smile Design [8]. A rectangular image of the patient’s smile is cropped from the patient’s face (Figs. 21 and 22). The cropped photo is then enlarged to facilitate manipulation. Eloquent landmarks are outlined of the patient’s smile, such as the border of the maxillary lip position in an “E” smile, the dental midline, and the border of the mandibular lip position (Fig. 23). This outline is evaluated as a composition without teeth and lips in the photo. The photo of the retracted anterior teeth is then brought into the keynote program. It is sized to fit the incisal position that was outlined from the cropped smile photo. Consistent camera angulation between the facial photograph and the retracted anterior photo facilitates superimposing and replacing these images. The retracted view is utilized in Digital Smile Design to work out intrinsic proportions of the anterior teeth and their placement in the mouth (Fig. 24). Numerical values that were recorded during the core esthetic evaluation are put into a grid of existing length and width (Fig. 26). The outline of the upper lip and lower lip is superimposed on retracted anterior tooth view. Average intrinsic values for the maxillary anterior teeth are used to proportion tooth silhouettes from the Digital Smile Design library. The outlines of the anterior teeth are then positioned into a pleasing composition for the patient’s face and lip position (Fig.  25). Teeth silhouettes help determine the position of the free gingival margin of the teeth as well as any changes in length or width of the teeth (Fig. 26). This new smile may be positioned into the patient’s face to evaluate the appearance of the proposed changes at the end of treatment [18] (Fig. 27).

Joint Based Malocclusion There are at least six occlusal camps in dentistry: conformative, bioesthetic, gnathologic, permissive, myocentric, and orthocranial—none of which have a clearly accepted advantage. Historically, occlusal tooth contacts and a fully seated

Patient Assessment

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Fig. 20  DSD images

Fig. 22  Cropped image of smile enlarged for DSD

Fig. 21  Digital smile design

Fig. 23  Eloquent landmarks of patient’s smile: Maxillary lip position, smile line, facial and dental midline and incisal edge position

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condylar position were used to reduce load and distribute force in an effort to treat the worn and eroded dentition. The thought was to limit bruxism through tooth contacts, which was shown to be unpredictable [19].

Fig. 24  Outline of ideal tooth proportions and positions placed in the smile frame

B. S. Vence

The permissive occlusal scheme may be utilized to reduce load on the joints, teeth, and the periodontium. Occlusal forces are managed through occlusal tooth contacts by altering muscle activity or redistributing occlusal forces. The occlusal goals for a permissive occlusal scheme include a fully seated condylar position [20], bilateral simultaneous posterior tooth contact in the centric arc of closure [21–23], mutually protected occlusion [24], anterior protected articulation [25], and a permissive angle of disclusion [26] (Figs. 28 and 29). The maxillary central incisors are the starting point to develop an occlusal scheme and idealize esthetics. In general, the maxillary arch deals with esthetics, and the mandibular arch deals with function. Therefore, setting the maxillary central incisors for optimal facial esthetics is the first order of

Fig. 25  Three planes of view: 12 o’clock, retracted frontal and occlusal views of current tooth position to better determine the ideal tooth positions

Patient Assessment

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Fig. 26  Existing and desired tooth proportions

Existing and Desired Tooth Proportions Tooth

3

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Fig. 28  Situational casts mounted with a facebow in a fully seated condylar position on a semi-adjustable Sam articulator

Fig. 27  Virtual mock-up of desired tooth proportions and position in patient’s face

Fig. 29

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B. S. Vence

Fig. 30  PSG of a patient demonstrating the respiratory event: Airway Resistance (yellow line), Esophageal Pressure (Pes), Arousal with increase in brain and heart activity (green circles)

treatment planning for a carefully crafted occlusal scheme that also distributes and minimizes occlusal loads. Recently, airway issues have been suggested as an important consideration in developing a well-designed occlusion. Unfortunately, little quality evidence exists in the literature to determine an optimal position for the central incisor for both facial esthetics and airway. A cephalometric analysis may help determine an ideal position for the central incisor. Landmarks such as SNA and SNB relate the maxillary arch and the mandibular arch to the cranial base and each other. However, due to the variation in “N” point, SNA and SNB need interpretation by the practitioner to optimize facial esthetics. They offer nothing to optimize airway. Basion may be a point that could relate to airway and facial esthetics.

airway or complete obstruction, the diaphragm pushes on the stomach contents, and with a drop in esophageal pressure in the pharynx causes acid to be drawn into the esophagus. A drop in esophageal pH may be recorded during a polysomnogram. This is described as sleep-related GERD [28, 29]. Sleep bruxism may follow a decrease in pH in the esophagus or an obstructive or resistance event [30] (Fig. 30). The salivary flow decreases during the nocturnal portion of the circadian rhythm. Tooth structure is altered by a combination of sleep-related GERD, an impairment in the buffering capacity of the saliva due to reduced quantity and the side-to-side bruxing pattern characteristic of sleep bruxism.

Airway Considerations

Template 1 Treatment Planning Session

As mentioned earlier, the worn, eroded and otherwise mutilated dentition was caused by excessive force due to bruxism from psychological stress. The theory was that the wear on the teeth was exacerbated by inadequate force distribution and force overload from poor occlusal contacts. The bioesthetic, gnathological, and permissive theories used a fully seated condylar position to control load on the teeth and minimize muscle activity. The myocentric theory uses a r­esting muscle position to minimize muscle activity and, thereby, load. Recent literature has identified sleep-disordered breathing as an association in the worn and eroded dentition [27]. One suggested mechanism is that with the resistance in the

Treatment Planning Session Patient Name: Date:

Diagnosis/Problem List The following diagnosis is based on a thorough diagnostic work-up, combining clinical radiographic and laboratory evaluations. Esthetic Facial:

Patient Assessment

Long Side of Face: Short Side of Face: Dorsum of Nose to the Left:____ to the Right:____ Incisal Edge Position: Gingival/Tooth Display: Arrangement: Contour: Color:

Occlusal/Functional Physiological Pathological Occlusion: Joint Pain, Muscle Pain, Tooth Wear, Tooth Fracture, Tooth Mobility, Tooth Sensitivity. Occlusion Parameters: *IPC: *Slide *CR=CO *Posterior Simultaneous Bilateral Tooth Contact in CR *Mutually Protected Occlusion *Anterior Guidance *Angle of Disclusion *Anterior Group Function or Canine Guidance

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Implant vs. Non-Vital Ferrule Effect (1 to 1–1/2  mm beyond core for crown retention) Canal space/post less than 1/3 total width of tooth (predictability) Oral Surgery: Medical:

Patient Considerations Social History. Esthetics (porcelain vs. gold, etc.) Color. Mercury/Metal. Attitudes/Wellness

Alternative Treatment Options Different treatment plans were developed that allow you to select a treatment based upon your specific needs, expectations, and desires at various levels of complexity. Your ultimate decision will be based on quality of life issues, and we will do our best to guide you through this process. 1. Do nothing.

Piper Classification: Right______ Left_____.

Dental/Structural Integrity Intact enamel dental cap. Intact enamel dentin junction. Intact dentin. Healthy Pulp. Caries: Existing Restorations: Amalgams: Composites: PFM: PFM FPD: FGC: AU Onlays: AU FPD: Porcelain onlays/inlays: Fractures: Cracks: Symptoms/Pain: Occlusion/Wear: Missing Dentition: Defective Margins/Micro-leakage:

Biological/Periodontal – Endontic Perio Type I II III IV. Endo: Vital vs. Non-Vital.

2. 3. 4.

References 1. Spear FM, Kokich VG, Mathews DP. Interdisciplinary management of anterior dental esthetic. JADA. 2006;137:160–9. 2. Rifkin R. Facial analysis: a comprehensive approach to treatment planning in aesthetic dentistry. Pract Periodontol Aesthet Dent. 2000;12(9):865–71. 3. Mack MR. Perspective of facial esthetics in dental treatment planning. J Prosthet Dent. 1996;75:169–76. 4. Ahmad I. Geometric considerations in anterior dental aesthetics: restorative principles. Pract Periodontol Aesthet Dent. 1998;10(7):813–22. 5. Kokich VO. Comparing the perception of dentists and lay people to altered dental esthetics. J Esthet Dent. 1999;11:311–24. 6. Gebhard W. A comprehensive approach for restoring esthetics and function in fixed prosthodontics. QDT. 2003;26:34. 7. Vig RG, Brundo GC.  The kinetics of anterior tooth display. J Prosthet Dent. 1978;39:502–4. 8. Coachman C, Calamita M.  Digital smile design: a tool for treatment planning and communication in esthetic dentistry. QDT. 2012:103–11. 9. Resnick CM, et  al. Evaluation of Andrews’ analysis as a predictor of ideal sagittal maxillary positioning in orthognathic surgery. J Oral Maxillofac Surg. 2018;76:2169–76. 10. Roe P. The influence of upper lip length and mobility on maxillary incisal exposure. Am J Esthet Dent. 2012:2116–25. 11. Sterrett JD, et  al. Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man. J Clin Periodontol. 1999;26(3):153–7.

80 12. Gargiulo AW, Wentz FM, Orban B. Dimensions and relations of the dentogingival junction in humans. J Periodontol. 1961;32:261–7. 13. Zettergren-Wijk L, Forsberg CM, Linder-Aronson S.  Changes in dentofacial morphology after adeno−/tonsillectomy in young children with obstructive sleep apnea-a five-year follow-up study. Eur J Orthod. 2006;28:319–26. 14. Lida-Kondo, et al. Comparison of tongue volume/oral cavity volume ratio between obstructive sleep apnea syndrome patients and normal adults using magnetic resonance imaging. J Med Dent Sci. 2006;53:119–26. 15. Winter R.  Visualizing the natural dentition. J Esthet Dent. 1993;5(3):103–16. 16. Morr T.  Understanding the esthetic evaluation for success. CDA. 2004;32(2):153–60. 17. Kois JC. Altering gingival levels: the restorative connection part I: biologic variables. J Esthet Dent. 1994;6(1):3–9. 18. Coachman C, Calamita M.  Digital smile design: a tool for treatment planning and communication in esthetic dentistry. QDT. 2012:106–10. 19. Clark GT, et al. Sixty-eight years of experimental occlusal interference studies: what have we learned? J Prosthet Dent. 1999;82:704–13. 20. Gibbs CH, Mahan PE, Wilkinson TM, Mauderli A. EMG activity of the superior belly of the lateral pterygoid muscle in relation to other jaw muscles. J Prosthet Dent. 1984;5(5):691–702. 21. Manns A, Mirralles R, Valdivia J, Bull R. Influence of variation in anteroposterior occlusal contacts on electromyographic activity. J Prosthet Dent. 1989;61:617–23. 22. MacDonald JWC, Hannam AG.  Relationship between occlusal contacts and jaw-closing muscle activity during tooth clenching: Part I. J Prosthet Dent. 1984;52(5):718–26.

B. S. Vence 23. Sheikholeslam A, Riise C.  Influence of experimental interfering occlusal contacts on the activity of the anterior temporal and masseter muscles during submaximal and maximal bite in the intercuspal position. J Oral Rehabil. 1983;10:207–14. 24. Manns A, Chan C, Miralles R.  Influence of group function and canine guidance on electromyographic activity of elevator muscles. J Prosthet Dent. 1987;57(4):494–501. 25. Williamson EH, Lundquist DO.  Anterior guidance: Its effect on electromyographic activity of the temporal and masseter muscles. J Prosthet Dent. 1983;49(6):816–23. 26. Weinberg L, Kruger B. A comparison of implant/prosthesis loading with four clinical variables. Int J Prosthodont. 1995;8:421–33. 27. Rouse J. The Bruxism Triad – sleep bruxism, sleep disturbance and sleep-related GERD. Inside dentistry; 2010 May. pp. 32–44. 28. Miyawaki S, Tanimoto Y, Araka Y, Katayama A, Imai M, Takano-­ Yamamoto T.  Relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions. Am J Orthod Dentofac Orthop. 2004;126:615–9. 29. Demeter P, Visy KV, Magyar P.  Correlation between severity of endoscopic findings and apnea-hypopnea index in patients with gastroesophageal reflux disease and obstructive sleep apnea. World J Gastroenterol. 2005;11(6):839–41. 30. Kato T, Rompre P, Montplaisir JY, Sessle BJ, Lavigne GJ.  Sleep bruxism: an oromotor activity secondary to micro-arousal. J Dent Res. 2001;80:1940. 31. Mack MR. Vertical dimension: a dynamic concept based on facial form and oropharyngeal function. J Prosthet Dent. 1991;66: 478–85.

The IDT Action Plan: Developing and Planning the Vision Brian S. Vence

Diagnostics in Contemporary Interdisciplinary Dentofacial Therapy (IDT) Once an assessment has been made of the current condition and position of the patients’ dentition relative to their face, the inter and intra-arch relationships in terms of structural integrity, the biologic health of the dentition, and systemic factors including airway, patients must decide how they want to lower their risk for future problems, and how they may want to enhance their stomatognathic system. When an agreement has been reached between the dentist and the patient about the conditions that will be treated, a prosthodontic workup is developed. The true etiologies of the patient’s issues are identified in five areas: Esthetics, Function, Structural Integrity of the Teeth, Biologic Health, and Systemic Health [1] (Fig.  1). These issues are further broken down into a dentofacial analysis: dental, periodontal, alveolar, dentoalveolar, alveoskeletal, skeletal, temporomandibular joint, airway, and facial soft tissue [2] (Fig. 2). Once these areas are identified and the patient has decided how they want to enhance and/or lower the risk for future problems [3], the interdisciplinary team of specialists is put together (Fig. 3). Four pieces in treatment planning, as described by Robert Relle, DDS, need to be considered and put together to work up an interdisciplinary dentofacial therapy case by all the specialists involved in the patient’s care: jaw to face, jaw to jaw, teeth to jaw, and tooth to tooth (Fig. 4). The central incisors are the starting point for an orthognathic, orthodontic, or prosthetic workup (Figs. 5 and 6) [4, 5]. The central incisors’ position needs to be agreed upon by the oral surgeon, orthodontist, and restorative dentist or prosthodontist. The condition of the teeth must also be considered when determining the position [6]. Complex cases typically involve malposition of teeth [7] combined with loss of tooth

structure, diminutive, or missing teeth. Space appropriation issues may be inter-arch, intra-arch, or a combination of the two. The team must develop proper space appropriation to restore the teeth to appropriate size and proportions, which includes optimal interradicular spacing. The issue is creating enough space to place transitional restorations for the orthodontist to visualize where to position the teeth. Also, dentoalveolar bone must be available to move the tooth roots into the ideal position to support the clinical crown. The idea is similar to setting up a denture for facial esthetics and function. However, teeth have roots in addition to the clinical crown, which must be housed in dentoalveolar bone (Fig. 7). If there is inadequate dentoalveolar bone for the desired tooth position, the bone needs to be developed [8]. If there is inadequate skeletal bone to support the dentoalveolar bone for the desired tooth position, the skeletal bone must be repo-

Treatment Planning Esthetics Function Structural Integrity Biologic Health

Frank Spear, State of the Art Esthetics; The Seattle Institute

Fig. 1  The four key aspects of patient assessment

B. S. Vence (*) Private Practice, Oakbrook Terrace, IL, USA © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_6

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82 Fig. 2  The fundamental components of a dentofacial analysis

Fig. 3  Risk assessment grading in patient assessment

B. S. Vence

The IDT Action Plan: Developing and Planning the Vision Fig. 4  Four pieces of facial structure and harmony in interdisciplinary dentofacial treatment

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Four pieces to fit when treating interdisciplinary cases.

OG S

OG S

Orthodontics

SFOT

SFOT

SFOT

Prosthetics

CEPHALOMETRICS SNA: 80 (79.6) degrees SNB: 77 (73.9) degrees ANB: 3.2 (5.7) degrees Wits Appraisal -1.0 (men) Max incisor position: 22 (16.2) degrees 4mm in front of N-A Mand incisor position: 25 (24.3) degrees 4mm in front of N-B Interincisal angle: 130 (133.9) degrees

Fig. 6   Cephalometric analysis measurements

Fig. 5   Cephalometric analysis demonstrating current and optimal position for the maxillary central incisor critical to orthognathic, orthodontic and esthetic planning

sitioned. The interdisciplinary team wants to position the teeth to maximize facial esthetics, function, and oral cavity volume for airway consideration [9] (Fig.  8). Computer assisted orthodontic planning is very helpful in developing the prosthodontic plan. Many treatment combinations may

be appropriate based on the workup of the IDT team such as expanding the arches with SFOT, MSE, restoring teeth, extraction of teeth, and orthognathic surgery. The goal is maximizing the patient’s well-being while minimizing procedures, time, and expense. The correct diagnosis is key. The ideal tooth position may be worked out with DSD [10] (Fig. 9) and computer assisted orthodontic and/or surgical planning (Fig. 10). In addition to the IDT specialists, the dental technologist is key to the case planning. The dental technologist is instructed in how to move the teeth

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B. S. Vence

Fig. 7   Edentulous patient smiling with denture. Denture demonstrated versus that of natural teeth. Limiting factor in optimal tooth position is often available dentoalveolar bone volume

Fig. 8   Optimal interincisal angle position and anterior coupling with condyle seated

Fig. 9  Digital smile design analysis and planning

to maximize facial esthetics and function while restoring the tooth form to ideal size and shape [11] (Fig. 11). The dental technologist may do this analogue or digitally. The situational casts are mounted in a Fully Seated Condylar Position (FSCP). FSCP is similar to centric relation, but it accounts for an adapted centric position. The mounted situational casts allow the technologist to work from the true inter-arch relationship of the maxilla and mandible to

develop the esthetic, functional [12], and airway considered goals [13] (Fig. 12). The technologist must bring together esthetics and function. The esthetic position of the maxillary anterior teeth is developed with DSD, facially generated treatment planning and core esthetic values. The functional relationship is developed based on the occlusal philosophy of the practitioners with a Bolton analysis [14] to determine the correct

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The IDT Action Plan: Developing and Planning the Vision Fig. 10  Digital impressions of current (white) and simulated desired (purple) tooth positions for facially generated outcome goals

Fig. 11  Tooth movement measurements for ideal tooth movements and rehabilitation of lost tooth structure based digital smile design, facially generated planning

Tooth

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size of the mandibular anterior teeth to develop the horizontal overlap and vertical overlap for coupling of the anterior teeth. The occlusal vertical dimension is determined based on the amount of vertical and horizontal overlap needed for anterior coupling from the anterior guidance and facial esthetics [15]. While digital workups are helpful, an analogue workup of the proposed orthodontic tooth movements and a prosthetic wax-up of the proposed tooth contours are essential. All team members must visualize the final goal and their role in attaining the goal. In terms of the

restorative dentistry, before initiating treatment or as early as possible in the treatment progression, a mock-up, provisional or denture is essential to obtain patient specific feedback. This feedback consists of how the proposed restorative dentistry looks in the patient’s face, how it interacts with the patient’s musculature when speaking and smiling, and the patient’s emotional reaction to the appearance of the restoration. This information cannot be obtained digitally. It must be obtained with a physical restoration placed in the patient’s mouth.

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Once all the procedures are agreed upon, a coordinated plan with a timeline is put together by the treatment coordinator (Fig.  13). The treatment coordinator is essential to keeping the team on task. The treatment coordinator must possess behavioral gifts and technical skills. A seasoned

B. S. Vence

hygienist is a good prospect or an extremely gifted assistant. Every specialist must put a high priority on these cases or too much time may pass, depleting the emotional currency built up in co-discovery, resulting in a patient management issue [16].

Fig. 12  Mounted situational casts demonstrating optimal orthodontic set up and diagnostic wax up

Fig. 13  Coordinated timeline of proposed interdisciplinary treatment

The IDT Action Plan: Developing and Planning the Vision

References 1. Spear FM, Kokich VG.  A multidisciplinary approach to esthetic dentistry. Dent Clin N Am. 2007;51:487–05. 2. Roblee RD, Bolding SL, Landers JM.  Surgically facilitated orthodontic therapy: a new tool for optimal interdisciplinary results. Compendium. 2009;30(5):3. 3. Kois DE, Kois JC. Comprehensive risk-based diagnostically driven treatment planning: developing sequentially generated treatment. Dent Clin N Am. 2015;59:593–608. 4. Vig RG, Brundo GC.  The kinetics of anterior tooth display. J Prosthet Dent. 1978;39:502–4. 5. Mack MR. Perspective of facial esthetics in dental treatment planning. J Prosthet Dent. 1996;75:169–76. 6. Sterrett JD, et  al. Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man. J Clin Periodontol. 1999;26(3):153–7. 7. Vence BS. Predictable esthetics through functional design: the role of harmonious disclusion. J Esthet Restor Dent. 2007;19:185–92. 8. Braut V, Bornstein M, Belser U, Buser D. Thickness of the anterior facial bone wall-a retrospective radiographic study using cone

87 beam computed tomography. Int J Peridont Restorative Dent. 2011;31:125–31. 9. Roblee RD, Bolding SL, Landers JM.  Surgically facilitated orthodontic therapy: a new tool for optimal interdisciplinary results. Compendium. 2009;30(5):5. 10. Coachman C, Calamita M. Digital smile design: a tool for treatment planning and communication in esthetic dentistry. QDT. 2012:1–9. 11. Smalley WM. Implants for tooth movement: determining implant location and orientation. JERD. 1995;7(2):62–72. 12. Spear FM. Chapters 31 and 32. In: McNeil C, editor. Science and practice of occlusion. Chicago, IL: Quintessence Publishing Co. Inc.; 1997. pp. 421–34, 437–56. 13. Rouse JS. The Bruxism Triad Sleep bruxism, sleep disturbance, and sleep-related GERD. Inside Dentistry. 2010;6(5):32–54. 14. Bolton WA. The clinical application of a tooth-size analysis. Am J Orthodont. 1962;48(7):504–29. 15. Mack MR. Vertical dimension: A dynamic concept based on facial form and oropharyngeal function. J Prosthet Dent. 1991;66:478–85. 16. Roblee RD. Interdisciplinary dentofacial therapy: a comprehensive approach to optimal patient care. Carol Stream, IL: Quintessence Publishing; 1994.

Sleep Disordered Breathing Considerations and Screening in Patient Assessment and Treatment Planning James Metz and Mickey C. Harrison

Introduction The goal of the medical profession is to enable conditions for healing. Dental professionals have traditionally been focused on the “fix,” not necessarily the anatomic, physiologic, and environmental factors that lead to a diseased or compromised state. Today, dentistry has the ability to evolve from the reactive diagnose and treat to the proactive predict and preempt. Dentists are an integral part of the health care team. The well-being and health of a patient will never be fully realized solely with care provided only by a physician, or only by a dentist; they need to work in concert for the best interest of each patient. People with insufficient or compromised airways do not just have these limitations during sleep; they use the same apparatus to breathe while awake as well. Dentistry is especially well-suited to intervene with airway concerns and sleep-disordered breathing (SDB) through screening and recognition, developmental, preventive, and treatment strategies. Enhancement of the oral cavity volume (OCV) may have a significant impact on diurnal breathing, which in turn may affect sleep quality. Why should a dental professional be concerned about sleep-disordered breathing? Obstructive sleep apnea (OSA) is a disease that consists of airflow disruptions during sleep, with a myriad of physiological consequences. Apneas are a complete cessation of airflow; hypopneas consist of a partial reduction in airflow associated with arousal and/or a decrease in oxygen saturation. Both events include intermittent hypoxia (IH), sleep fragmentation, and marked fluctuations in intrathoracic pressure, sympathetic activation, and elevation of heart rate and blood pressure [1, 2]. With time, many conditions may develop impacting the physical and mental health of the patient and put one at risk for premature death. Cardiovascular consequences can include hypertension, stroke, congestive heart failure, atrial fibrillation, coronary J. Metz (*) · M. C. Harrison The Metz Center, Columbus, OH, USA

artery disease, and sudden cardiac death [3–5]. Neurocognitive issues may include daytime sleepiness, work-related or motor vehicle accidents, and alterations in neuropsychologic and executive functions. [3, 6–11] Insomnia, depression, and anxiety can also be comorbidities of OSA [12–17]. Metabolic disturbances including altered insulin resistance and type 2 diabetes mellitus are common, as is sexual dysfunction [18–22]. Untreated obstructive sleep apnea has been shown to increase risk for cardiovascular and all-cause mortality, and long-term survival is impacted by severity of the SDB, especially when untreated [23–26].

The Importance of Screening The word screening in medicine and epidemiology has two major meanings that are important to differentiate [27]. Population screening includes the organized application of diagnostic testing in mostly asymptomatic or undiagnosed symptomatic individuals, with the goal of initiating treatment or preventive strategies to decrease the morbidity and mortality associated with the disease [27]. Clinical screening consists of a series of intermediate tests performed on a symptomatic patient for whom a diagnosis has not yet been established [27]. The concept of screening has an implied assumption that early detection will be more effective than later treatment in terms of disease outcome or development of comorbidities [27]. Several features of obstructive sleep apnea suggest that it may be a suitable condition for screening programs for general populations and more specific high-risk groups; OSA is a significant health problem in terms of high prevalence, elevated levels of morbidity and mortality, and increased public safety risk [27]. Recent data from the Wisconsin Sleep Cohort Study estimates moderate to severe SDB (that is, an AHI ≥15 events/h) for the following population segments: 10% among 30 to 49 year old males; 17% among 50–70 year old men; 3% among 30 to 49  year old females; and 9%

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_7

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among 50–70 year old women [1]. These estimates demonstrate increases between 14% and 55% based on the subgroup over the last 20  years [1]. In 2015, an American Academy of Sleep Medicine (AASM) task force released quality measures for the care of adults with obstructive sleep apnea; the first outcome is improved detection and recognition of OSA symptoms and severity to promote evaluation and diagnosis of the disorder [28, 29]. It is known that treatment can reduce costs, improve quality of life, and ­ decrease morbidity from symptoms and related conditions [29–36]. Despite this, obstructive sleep apnea remains considerably underdiagnosed and undertreated [37–39]. Studies have found that sleep disorders are common but rarely addressed by primary care providers (PCP); decrements in daytime function or insomnia symptoms are not recognized as consequences of OSA [28, 40–42]. Direct questions about sleep health are often not included in health history questionnaires, and even with a review of symptoms form, sleep symptoms may not be sufficiently sensitive to identify elevated sleep-disordered breathing risk or warrant further follow-up [28, 43–45]. Individuals with known risk factors for obstructive sleep apnea such as obesity, hypertension, and type 2 diabetes are often not screened for sleep symptoms, assessed or referred to a sleep medicine specialist [28, 46]. Patients with OSA may have contact with the health care system for several years before a diagnosis of sleep apnea is arrived at. Common conditions that individuals seek care for are musculoskeletal issues; cardiovascular disease (CVD); endocrine, nutritional, and metabolic concerns; diseases of the nervous, respiratory, gastrointestinal, and genitourinary systems; skin and subcutaneous tissues; infections; and ear, nose, and throat issues [46]. Of all comorbid diagnoses, substantially elevated health care utilization exists for CVD and especially high blood pressure in OSAS patients [47]. Given this body of knowledge, recent findings from the U.S.  Preventive Services Task Force conclude that there is insufficient evidence to “determine the balance of evidence and harms of screening asymptomatic adults for obstructive sleep apnea.” [48] On the other hand, the AASM finds that diagnosis and treatment of sleep-disordered breathing are warranted based on short-term and lifetime health cost savings [49]. Prior to treatment, patients with obstructive sleep apnea are more likely to be admitted to the hospital, and incur higher health care costs than matched controls; the magnitude of medical costs may correlate with the sleep-­ disordered breathing severity [37, 49]. The economic burden of untreated OSA is significant, accounting for billions of dollars per year in health care spending, work-related and motor vehicle accidents, and diminished work attendance and productivity [50]. It would behoove governments, transportation agencies, corporations, and insurance entities to better understand the implications of untreated sleep-­ disordered breathing and the advantages of treatment.

J. Metz and M. C. Harrison

The Role of Dental Professionals Screening and monitoring for systemic disease or risk factors for disease in the dental office are important components toward more effective disease prevention, control, and health care delivery [51]. The dental setting can provide an important entry point into the health care system for people who do not see a physician on a regular basis [51]. Approximately 65 to 70% of American adults visit the dentist per year, with 10 to 20% of those not having seen a medical doctor in the previous year [51, 52]. Therefore, in any given 24 month period, the majority of the US population has seen an oral health professional [53]. Based on these statistics, dentists are well-­ positioned to assist in strategies to prevent the onset of or control disease severity for conditions such as obstructive sleep apnea and other chronic, comorbid conditions. As part of the interdisciplinary health care provider team, dental professionals can offer screening as an alert mechanism to patients who may warrant further follow-up by a physician for a definitive medical diagnosis [51, 52, 54]. In the future, dentists may serve a role as primary care provider for their patients [53]. This is especially relevant given the fact that chronic diseases are the leading cause of death among American adults; 50% of adults age 21 and older have at least one chronic disease; the prevalence of chronic diseases increases with age (including OSA); and the US population is quickly aging [53, 55]. The increased needs of the patient population may overwhelm the capacity of primary care physicians. Studies have explored the attitudes of dentists, physicians, and patients regarding chairside screening for medical conditions in the dental setting. The oral health professionals who participated were found to consider medical screening important and were willing to implement it into their daily operations [56]. Primary care physicians regarded chairside medical screening in a dental setting to be valuable and useful; their most important criteria were patient willingness to participate [57]. A majority of dental patients participating in the research were willing to have a dental professional conduct screening for various chronic conditions; the fact that the test was not performed by a medical doctor was the least important factor that might impede implementation [58].

 ethods of Screening for Sleep-Disordered M Breathing in the Dental Practice Many signs and symptoms may be recognizable in the dental practice [59]. A review of the medical history will show presence of comorbid conditions such as hypertension or other cardiovascular disease; hyperlipidemia; or type 2 diabetes mellitus [18, 59–63]. Dental and clinical examination may

Sleep Disordered Breathing Considerations and Screening in Patient Assessment and Treatment Planning

show presence of a worn dentition; missing teeth; tongue scalloping; enlarged palatine tonsils, tongue or soft palate; and a high Mallampati or Friedman score [59, 64–70]. Lateral cephalometric radiographs can also provide data indicative of an airway issue, including airway length; hyoid bone position; upper and lower face heights; and excessive soft tissues including tongue, soft palate, and lymphoid tissue [71–73]. Questionnaires can also be utilized to screen dental patients for potential sleep-related breathing disorders. More than 100 surveys, questionnaires and scales are available for use [74]. The STOP-Bang, Berlin Questionnaire and Epworth Sleepiness Scale (ESS) are useful tools for the dental team to assess an individual’s risk for sleep-disordered breathing in undiagnosed subjects, as well as for tracking improvement of symptoms through the course of treatment [75–77]. These surveys certainly will help assist in finding patients who need to be referred for a medical evaluation for suspected obstructive sleep apnea, but should NOT be relied upon as the sole screening method; it has been shown that individuals with an apnea-hypopnea index well above the severe threshold of 30 events/h, up to an AHI of 100, may exhibit no daytime symptoms and score zero on the Epworth scale [78]. That is why it is essential to have an objective method to screen patients for suspected or undiagnosed SDB in combination with their report of subjective symptoms. High resolution pulse oximetry is an indispensable tool for dentists who are screening for sleep-disordered breathing.

High Resolution Pulse Oximetry Pulse oximetry enables oxygenation to be continuously monitored in a simple and non-invasive fashion [79]. This method entails utilizing a medical device that measures the oxygen saturation of a subject’s blood and changes in blood volume in the skin, generating a photoplethysmograph; the heart rate is also displayed [80]. A blood-oxygen monitor displays the percentage of arterial hemoglobin in the oxyhemoglobin configuration [80]. Normal overnight mean oxygen saturation (SaO2) is 96.5% (±1.5%) in healthy individuals [81, 82]. SaO2 decreases slightly with increasing age, with values of 96.8% in 1–10  year olds, to 95.1% in those older than 60 years; ethnicity, gender, and weight do not greatly influence normal values [81]. Nocturnal SaO2 does differ with altitude; healthy individuals have been shown to have oxygen levels as low as 71% at 6400 meters during sleep [81, 83]. Earlier generations of oximeters have four or more second averaging times and are widely utilized in polysomnography, which is a full-montage overnight sleep study performed in a staffed laboratory. Polysomnograms (PSG) are the gold standard for diagnosis of any sleep disorder [84]. High resolution pulse oximeters (HRPO) are available with 1 or 2  s signal

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averaging times. Optimal HRPOs have a high horizontal resolution of the oxygen saturation (1–2 s average); a high vertical resolution of SpO2 (0.1% SpO2); and a high horizontal resolution of the heart rate (1–2 s); they also employ algorithms that compensate for patient movement during sleep to reduce motion artifact [85]. A comparison of five different pulse oximeters used in sleep medicine for obstructive sleep apnea screening showed a difference of the internal signal processing among the devices [86]. The reproducibility tests demonstrated that the best device was the one with the signal resolution of 0.1% SaO2. That is, apnea events with desaturations of ≥4% are most accurately detected with the HRPO that has the highest vertical resolution; the measurements at this resolution are closest from night to night due to the desaturation detection [86]. The high resolution pulse oximeter found to be a superior screening tool for SDB as compared to other pulse oximeters in the model PULSEOX 300i (Konica Minolta Sensing, Inc., Osaka, Japan), which is an HRPO wrist-worn device with a sampling frequency of 1 Hz, SpO2 resolution of 0.1%, and a 3 second averaging time [86, 87]. Other features of the 300i include a large capacity of 300 h of high resolution data storage, which is easily downloaded via USB cable; 30 h of continuous operation powered by one AAA battery and battery level indicator; and a 6 year service life [88]. There are three indexes that are often utilized to evaluate oxyhemoglobin in association with pulse oximetry: oxyhemoglobin desaturation index (ODI); time-domain index; and frequency-domain index [89]. These indices are commonly used to screen for and predict apnea-hypopnea severity [90]. The ODI has a significantly stronger correlation and a better diagnostic performance than the other two; it is correlated with the parameters that measure sleep-disordered breathing from nocturnal polysomnography, and is highly sensitive and specific at different degrees of OSA-H severity [86, 88, 89, 91]. Dental professionals who are screening their patient population for sleep-disordered breathing can employ high resolution pulse oximetry. The 300i utilizes SatScreen software from Patient Safety, Inc., to run three nights of study during sleep in the patient’s home [92]. SatScreen will provide information including respiratory disturbance index (RDI; apnea plus hypopnea plus respiratory effort-related arousal); oxygen saturation levels and desaturation events; cycling time and cycling severity index (which deal with the occurrence of respiratory events); heart rate; and movement [92]. The patient safety software relies on algorithms to accurately perform slope analysis on the data points, which provides much more accurate information than standard pulse oximeters that analyze square graphs and lose subtle data points with averaging. The HRPO with SatScreen software is not considered diagnostic for sleep-related breathing disorders; if there are concerns with the reports, the patient is referred to a sleep medicine specialist for diagnosis with polysom-

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nography. However, the results of the HRPO are highly correlative to PSG, and through the screening process, the dentist and the patient will have a good idea of the findings of the overnight sleep laboratory test [89, 90, 93]. Benefits of screening with the 300i include ease of dispensing the device, which can even be transported via the mail service; immediacy of being able to conduct screening, because it eliminates the wait time for a bed in a sleep laboratory; and the inexpensive nature of a night of study as compared to full polysomnography. It has been shown that being in the artificial environment of a sleep laboratory can create a “first night effect,” impacting sleep quality and the results of the study; also, there can be night-to-night variation with SDB findings [94–101]. The high resolution pulse oximeter can easily overcome these issues by testing the subject in their home where they are comfortable, and using three nights of study to account for any anomalous data or circumstances. Given the power of the HRPO, the dentist has a unique opportunity to recognize those with sleep-disordered breathing and refer them for polysomnography for a diagnosis, in many cases allowing intervention earlier on in the disease process [102].

 igh Resolution Pulse Oximetry and Oral H Appliance Therapy Once a patient has been diagnosed as having obstructive sleep apnea, the gold standard for treatment is continuous positive airway pressure (CPAP) therapy [103]. However, there are many drawbacks to CPAP, including issues with side effects, claustrophobia, and a poor compliance rate; patients are less likely to continue PAP therapy if they have less severe SDB [104–109]. Oral appliance therapy (OAT) with a mandibular advancement device (MAD) is provided by oral health care professionals and is indicated for patients with mild to moderate OSA, and in cases of CPAP failure or rejection [110]. More and more studies are demonstrating that OAT is also effective for those with severe sleep apnea, and patients typically wear the device through the night; mean disease alleviation has been shown to be higher for oral appliance therapy as compared to CPAP due to the amount of hours used [111–117]. One of the main challenges in providing successful oral appliance therapy for SDB patients is being able to effectively titrate the device for optimal performance. There is no gold standard that has been defined for the titration protocol for mandibular advancement therapy [118]. It has been shown that a dose-dependent effect of mandibular protrusion may exist, with greater protrusion producing larger improvements in OSA severity; however, this does not universally apply to every individual [119–122]. A common method to determine the optimal protrusion can consist largely of trial and error. Excessive mandibular advancement may also con-

J. Metz and M. C. Harrison

tribute to unwanted dental morbidity; 1.18 N/mm are generated for every 1 mm of protrusion [123]. Different methods exist for adjusting a mandibular advancement device for sleep apnea patients. Remote controlled positioners can be utilized while the individual is asleep during a PSG to gauge different positions [124–127]. Appliances can be self-adjusted by the patient to subjective comfort and resolution of symptoms, and then further titrated during a follow-up laboratory sleep study [128–130]. A temporary advancement device can also be employed during a polysomnogram, with confirmation of the position’s efficacy with a second PSG [131]. Combining the patient’s subjective report of symptom resolution with objective data about the oxygen desaturation index is another technique that can be utilized [132]. The 300i high resolution pulse oximeter with SatScreen software is a powerful tool for titrating a MAD; multiple nights of study can be performed with little expense and inconvenience to the patient, and the studies are conducted in the comfort of their natural home surroundings. Once the individual’s report of symptoms agrees with the improvement in oxygen saturation and heart rate on the SatScreen reports, the patient is referred back to the sleep physician for a confirmation polysomnogram or home sleep test to be interpreted by a sleep medicine specialist.

Future Direction for Dentistry Dental professionals are in a unique position to serve an entire subset of the sleep-disordered breathing population, namely those individuals with upper airway resistance syndrome (UARS). Patients with UARS exhibit increased respiratory effort and airflow limitation during sleep, without the intermittent hypoxia that is a hallmark of obstructive sleep apneas and hypopneas [133–136]. Clinical presentation includes excessive daytime sleepiness, snoring, mood imbalances, and insomnia; polysomnography will show no desaturation events, but flattening of the airflow curve indicative of inspiratory flow limitation and associated arousals will be apparent [133–136]. The International Classification of Sleep Disorders does not specify UARS as a specific entity; these individuals are classified as a subgroup of obstructive sleep apnea [135]. However, respiratory effort-related arousals (RERAs) are described as distinct events occurring during sleep and requiring scoring during the study interpretation [135]. UARS patients may exhibit cognitive impairment, irritability, anxiety and depression, headache, gastroesophageal reflux disease, irritable bowel syndrome, alpha-delta sleep, bruxism, and orthostatic syncope; many of these signs and symptoms closely resemble those of the functional somatic syndromes [133, 134, 137–139]. Individuals with upper airway resistance syndrome are typically younger, less overweight, and exhibit a high

Sleep Disordered Breathing Considerations and Screening in Patient Assessment and Treatment Planning

female to male ratio as compared to OSA patients [133, 135]. UARS sometimes is described as a precursor to or subset of obstructive sleep apnea and will progress from one to the other in the presence of advancing age and weight gain, or described as a separate clinical entity [133–136]. Physical examination of these people may present with nasal obstruction; soft tissue anomalies including a low soft palate and long uvula; and craniofacial abnormalities including high and narrow hard palates, and malocclusions including increased overbite [133, 135]. The first recommended treatment for UARS is continuous positive airway pressure, but the long-term acceptance and compliance are especially poor [133, 140, 141]. Other treatment options include cognitive behavioral therapy for insomnia; surgical procedures such as septoplasty and turbinate reduction, distraction osteogenesis, or orthognathic surgery; mandibular advancement with oral appliance; and orthodontics in conjunction with rapid maxillary expansion [133– 135]. OAT is an important modality for treatment of UARS [133–135, 142, 143]. Surgical treatment should favor less invasive procedures with lower risk of complications and side effects [134]. Surgically facilitated orthodontic therapy may prove to be an ideal procedure to care for the UARS patient in such a fashion; further research is warranted to link an expanded oral cavity volume and reduction of symptoms secondary to airflow limitations. Improving the position of the dentition within the alveolar housing and providing more space for the tongue intraorally may allow the interdisciplinary dental team to preempt comorbidities and possible progression to more severe sleep-disordered breathing in the future. Recording and tracking outcomes will be invaluable to shape the future direction of such therapy. The high resolution pulse oximeter merits clinical trials as well, to elucidate its role in the preoperative and postoperative measurement of a patient’s physiology when SFOT intervention takes place. Someday UARS patients may be able to be managed outside of the purview of a polysomnogram, freeing up bed space and sleep specialist time for those who have more severe and complicated issues.

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Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology Mitra Sadrameli, E. Dwayne Karateew, and Mel Mupparapu

Abbreviations FOV Field of view LFS Long face syndrome OSAS Obstructive Sleep Apnea Syndrome OGS Orthognathic surgery PNS Perineural spread SDB Sleep-disordered breathing AP Anteroposterior PPF Pterygopalatine fossa PhMT-bone Phenotype modification therapy via bone grafting

Introduction Two-dimensional (2D) radiographs are commonly used in orthodontic treatment planning. In pre-orthodontic evaluation and during tooth movement, 2D images are limited in their ability to assess anatomic areas such as the thickness of the buccal plates and the three-dimensional (3D) relationships between anatomic structures. Unlike 2D images, carefully selected and evaluated 3D imaging allows accurate analysis and measurement of the alveolar ridge height and width, teeth to bony housing relationship, as well as assessment of the oropharyngeal and nasopharyngeal airway and other vital structures. M. Sadrameli Private practice, Chicago, IL, USA e-mail: [email protected] E. D. Karateew (*) University of Illinois at Chicago, Chicago, IL, USA e-mail: [email protected] M. Mupparapu University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA e-mail: [email protected]

Interdisciplinary dentofacial therapy is demanding and often involves complex cases, necessitating collaboration with the goal of preserving and retaining natural dentition [1–3]. During the treatment planning phase, the use of CBCT imaging provides unique and comprehensive assessment of the dentoalveolar, the skeletal relationships, as well as the health status of various anatomic sites such as the temporomandibular joints (TMJs). In addition, virtual surgical 3D simulation and planning allow for in-depth evaluation of the anatomy and potential anatomic or pathologic challenges. The primary role of Surgically Facilitated Orthodontic Therapy (SFOT) is to ensure correction of the patient’s malocclusion which is often a result of skeletal disharmony and/ or dental space inadequacies. The ultimate goal is optimizing inter-arch and intra-arch alignment, while keeping the dentition within the confines of the alveolar bone [4]. In addition to addressing potential insufficient alveolar bone volume/ topography, malocclusions, compromised arch form, and any potential esthetic concerns which may arise from more traditional therapeutic modalities, SFOT may accelerate orthodontic treatment time by up to 300% [5–9]. 3D analysis and planning facilitate this process by allowing (1) accurate analysis, (2) virtual planning, (3) virtual surgery, (4) 3D printing of guides and models when needed, (5) comparison studies between the planned and actual results, as well as evaluation of progressive changes over time [10].

Pretreatment Evaluation with CBCT The 3D pretreatment evaluation of the soft and hard tissues provides detailed information regarding the anatomy and its variations, pathology, as well as post-surgical changes. The region of interest can be viewed at scale, magnified, and rotated to visualize contours and relationships between the anatomic sites. Depending on the size and quality of the 3D scan, various layers can be virtually subtracted to allow for better visualization from different angles. Linear, angular, as

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_8

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well as volumetric measurements provide clinically accurate information [1, 10]. When idealized measurements and relationships are available, comparison with the patient information may provide better understanding of the problems at hand and the type of treatment needed [10, 11]. Pretreatment evaluation can be divided into multiple phases: (a) volumetric analysis phase, (b) analysis phase, and (c) treatment planning phase.

Volumetric Analysis Phase SFOT enables excellent outcomes in terms of not only esthetics, but also function and occlusal stability, while promoting long-term success [12]. The key in moving forward with the case is the diagnostic aspect of bone morphology, as well as anticipation of the path of tooth movement, which when deficient, may necessitate creation of adequate bony matrix via grafting procedures [12].

Neighboring Anatomy Of equal importance in the preparation for all surgeries is not only the evaluation of areas which will directly bear the impact of the surgical procedure, but also those that appear in the remainder of scan. The following topics will address the areas seldom addressed in the SFOT surgical procedure itself, yet significant findings in these areas may alter the treatment plan and in some cases may address life altering diseases. Every structure visible within the Field of View (FOV) of the scan should be evaluated and compared with normal. This applies to anatomic structures traditionally treated and manipulated by dental practitioners, as well as those structures which until two decades ago were only visible in images acquired by medical practitioners.

Skull Base Evaluation of intracranial structures such as the sella turcica is important to determine deviation from normality. Larger than normal sella turcica or those with irregular walls should prompt the dental clinician to request medical consultation. Abnormal sella and clival, as well as skull base findings especially when patients present with radiographic signs of mild and previously undetected fibro-osseous lesions involving solitary or multiple skull bones should be noted and discussed with the patient [13]. In addition, evaluation of the skull base

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must include determination of patency of the foramina, structural harmony, bone health, as well as any asymptomatic or previously undetected pathology in that region.

Carotid Artery Calcification Incidental identification of internal carotid calcifications is not uncommon especially in the older individuals. While all calcifications should be noted and discussed with the patient, it is not the visible calcified entities that are of utmost significance. Rather, it is the non-calcified atheromatous plaque, within the internal space of the carotid artery, which are not seen in CBCT or other dental images, that is considered a significant important predictor of stroke. As such it is of great importance to discuss presence of visible calcifications in this area with and encourage the patient to seek further evaluation, if he or she has not previously done so.

 aranasal Sinuses and Nasal Cavities P A thorough review of the CBCT scan will involve the evaluation of visible areas of the paranasal sinuses: maxillary, ethmoid, sphenoid, and frontal sinuses [14]. Sinonasal pathology must be diagnosed and taken into consideration. These types of pathology may be located in the surgical area, thereby directly affecting the surgical procedure. Alternatively they may be located distant from the surgical site, yet indirectly affect the surgical procedure. Maxillary Sinuses The maxillary sinuses present with many interesting and unique conditions. Evaluation of the maxillary sinuses prior to dental implant placement with or without sinus elevation procedures is among the most common reasons for CBCT imaging in dental medicine [15]. Other complex surgical procedures may also directly or indirectly involve the maxillary sinuses, as such understanding the incidental antral findings and pathologies is important. Pathologies of the maxillary sinuses can be classified into inflammatory, iatrogenic, traumatic, neoplastic, odontogenic, congenital, and bone-related [16]. Many of these conditions are outside the scope of this chapter but understanding the range of diseases in this area highlights the familiarity required by the clinician when reviewing the patient’s CBCT scan. Odontogenic Sinusitis In CBCT imaging, the Schneiderian membrane thickening and presence of fluid within the maxillary sinus cavities or for that matter any of the paranasal sinuses will appear as opacities, isodense to soft tissue. The opacification within

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology

the sinus cavities may be a harbinger of disease or may be considered a variation of normal. Distinguishing the differences between the two allows referral to the correct clinician if treatment is required. It is important to note that, as with everywhere else in the scanned image, CBCT allows for evaluation of the outline of the opacification seen in the maxillary sinuses but offers no information about the characterization and makeup of the soft tissue itself. As such to understand the nature of the opacification, at times we must rely on indirect radiographic signs and the effect on the adjacent structures or both. Other times, further clinical, surgical, and/or imaging evaluation is needed to provide a definitive or differential diagnosis. Presence of opacification is not always a sign of disease. In an asymptomatic patient, a narrow and subtle opacification adjacent to an intact sinus floor or following healthy sinus walls may be suggestive of normal thickening of the Schneiderian membrane or an allergic condition. Rarely such a finding in the absence of an inflammatory source denotes a de novo inflammatory response of the sinus. Commonly, the etiology for an inflammatory response of the Schneiderian membrane is an odontogenic source, be it rarefying osteitis of pulpal origin or periodontal disease. Either of these conditions can cause a focal or general opacification at the sinus floor, or one that may occupy the inferior volume, or in the presence of longterm and/or significant odontogenic infection, may occupy most or all of the volume of the sinus cavity. Presumably in the treatment planning phase for SFOT, presence of odontogenic conditions adjacent to the maxillary sinuses, and in the direct path of the surgery, will have been identified. When opacification within the sinus cavity is noted, further evaluation of the adjacent teeth to rule out subtle and missed odontogenic teeth-related lesions is crucial. These sinus opacifications may, at times, act as an indirect marker for missed teeth-related inflammatory diseases (Fig. 1). Suspicion of odontogenic sinusitis should warrant periodic evaluation of the sinuses during and after successful elimination of the origins of the inflammation.

Non-odontogenic Sinusitis In CBCT images, the non-inflammatory lesions of the maxillary sinuses share many radiographic presentations. While the experienced interpretors of CBCT images may be able to identify subtleties of various lesions, the casual interpretor may not. As mentioned before any thickening of the Schneiderian membrane with or without fluid accumulation in the sinus cavities present as an opacification isodense to soft tissue. This lack of characterization renders definitive diagnosis difficult and at times impossible. However, there are exceptions to this lack of clarity.

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Fig. 1  Sagittal CBCT of right maxilla. Tooth #2 shows concurrent endodontic and periodontal lesions. Note the floating in air appearance of the tooth. Also note the superior displacement of the sinus floor creating a “halo” superior to the apex (white arrow). The differential diagnosis for the opacification at the sinus floor is odontogenic sinusitis associated with the odontogenic lesion of tooth #2

Acute and Chronic Sinusitis Sinusitis is the inflammation of the sinuses. The etiology is varied and may be infectious having bacterial, viral, or fungal origins, or allergic in nature. The inflammation results in occlusion of the maxillary sinus ostium, causing a blockade to the sinus drainage pathway. This in turn results in retention of mucous and creating optimum conditions for bacterial growth. For the purposes of this chapter, sinusitis conditions are divided into two groups, acute and chronic. Clinically, the distinction between the two is based on an arbitrary timeline. Acute sinusitis is defined as one with symptoms lasting less than 4  weeks, whereas when symptoms last longer than 8 weeks, the condition is referred to as chronic sinusitis. With the exception of a few features, the imaging findings for both types of sinusitis are nonspecific. A characteristic feature on CBCT/CT sinuses with chronic sinusitis is hyperostosis (osseous thickening) of the sinus walls (Figs. 2 and 6). Equally characteristic for acute sinusitis is presence of air-fluid level (Fig.  3) and/or stringy opacification punctuated by air-density bubbles (Fig. 2).

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Fig. 2  Axial CBCT at the level of maxillary sinuses showing stringy opacification punctuated by air-density bubbles in the right sinus (short arrow) seen in acute sinusitis. Left maxillary sinus shows thickening of the posterolateral wall seen in chronic sinusitis (Long arrow)

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Fig. 4  Sagittal CBCT through right maxillary sinus showing mucous retention pseudocyst noted on the floor of the sinus (short arrow)

within the maxillary sinuses may be a sign of chronicity of the sinus disease. In the presence of underlying immunocompromised conditions however, consultation with the otorhinolaryngologist to differentiate between true antroliths and calcifying infections such as fungal infections is suggested.

Mucous Retention Pseudocysts

Fig. 3  Coronal CBCT slice in the region of maxillary sinuses shows significant air-fluid levels in the left maxillary sinus (orange arrow) suggestive of acute maxillary sinusitis. Also note the incidental presence of antroliths (white arrow) towards the sinus floor on the same side.)

Antroliths Antroliths are calcified radiopaque masses found within the maxillary sinuses and are considered common findings. When asymptomatic they may not be of consequence. Asymptomatic antroliths concurrent with opacification

Mucous retention pseudocysts (MRCs) are common occurrences within the maxillary sinuses. Radiographically, it is described as a dome shaped, homogeneous soft-tissue density mass, without cortical lining (Fig.  4). MRCs are not exclusively seen in the maxillary sinuses, however, when present, they are found on all the walls with high frequency. Clearly, those with an association to the sinus floor are of utmost interest to the dental clinicians. They are not considered contraindication to surgical procedures such as sinus elevation, as they are not inflammatory or tumoral based, and are considered self-limiting. They appear to be distributed equally between the right and left sinuses, as well between male and females [17]. In the 1990s and early 2000s, the relationship between MRCs as benign incidental findings with no effect on the outcome of surgical procedures within the sinus cavity was thought to be inconclusive, with one camp correlating them with mucosal pathology [18, 19] and more recent authors suggesting no correlation [17, 20]. The absence of a destructive nature and the transient or stable characteristic of MRCs is responsible for an advocacy of a “wait and see” strategy. Intervention is suggested only if a good reason can be offered.

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology

Mucocele A mucocele is a pseduocyst formation with a secretive epithelial layer filled with aseptic, mucous, as well as dense liquid. This is an expansile lesion with the ability to slowly erode the sinus walls and expand the volume of the sinus cavity. While they are predominantly seen in the frontal (60%) and ethmoidal (30%) sinuses [21], their presence in the maxillary sinuses should not be underestimated. In the maxillary sinuses, mucoceles are relatively rare (≤ 10% of all report cases) [21]. The pathophysiology of the lesion may be related to two factors: a) obstruction of the maxillary sinus ostia due to anatomic anomalies, trauma, benign, or malignant tumors or b) presence of persistence inflammation [21]. A true mucocele, unlike MRCs may exhibit destructive behavior such as expansion of the sinus walls and erosion of the underlying bone [21]. While in early literature, the terms MRCs and mucoceles were used interchangeably, they are two distinct conditions, with MRCs requiring no attention other than periodic follow-­up and mucoceles requiring immediate attention.

Maxillary Sinus Polyps Polyps are not uncommon in the maxillary sinuses. Radiographically, they exhibit an irregular shape, and similar to mucocele, they may expand the sinus cavity. They are highly reactive and may erode the walls and even grow beyond the confines of the sinuses typically extending to the ipsilateral nasal cavity, with reports of extension to the pharyngeal airway via the posterior nares. Presence of erosive lesions of the sinus walls is of great concern, and when radiographically noted, patients need to be referred to an otorhinolaryngologist. Presence of multiple lesions with erosive and expansile characteristics underscores the need for careful evaluation of the maxillary sinuses.

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Tumors of the oral cavity and paranasal sinuses can spread along the nerves to areas considerably removed from the primary tumor. Perineural spread (PNS) indicates that the tumor cells have left the original site and have travelled along the length of a nerve to distant anatomical location(s) [24]. In head and neck cancers, PNS is often accomplished along the major nerves, which act as conduits for transfer of malignant cancer cells from one location to another [24]. Given the extensive network of fibers in the head and neck area, the most prominent neural conduits are the trigeminal and the facial nerves [24]. As a result, PPF in CBCT images becomes a key landmark in the detection of neural metastasis. Early detection of tumoral lesions significantly increases successful treatment before it can spread to multiple neighboring structures and areas, thereby becoming unmanageable. Of importance to the dental practitioner is that the anterior wall of the PPF is shared with the posterolateral wall of the maxillary sinus (Fig. 5). In the axial view of the CBCT images, special attention should be given to this area. Unilateral irregular enlargement of the fossa, erosion, or effacement of the walls of the PPF are significant red flags, which should compel the clinician to refer the patient for further evaluation including advanced imaging in order to determine the etiology of these findings (Fig. 6). CT and MRI are complementary in evaluation of the PPF, with MRI showing superior ability in characterizing the tumor and determining the extension and perineural spread if any [22].

Pterygopalatine Fossa The pterygopalatine fossa (PPF) is a small but important cone-shaped space located posterior to the maxillary sinus [22]. While the space itself does not serve a specific function, PPF acts as a highway through which several important structures transverse via eight different skull foramina, thereby allowing communication between their ipsilateral nasal and oral cavities, orbit, pharynx, and the infratemporal and middle cranial fossae [23].

Fig. 5  CBCT axial view at the level of maxillary sinuses showing the symmetrical dimensions of the left and right pterygopalatine fossae (arrows)

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Fig. 6  CBCT axial view at the level of pterygopalatine fossae: Note the larger dimensions of the left fossa (long arrow). Also note the thickening of the posterolateral wall of the left maxillary sinus suggesting chronic sinusitis (short arrow)

Airway Evaluation Assessment of the morphology and function of the upper airway is of utmost importance. Sleep-disordered breathing (SDB) represents a range of sleep disorders from simple snoring to severe Obstructive Sleep Apnea Syndrome (OSAS) [25]. OSAS is a multifactorial condition, which not only involves narrowing of the airway space, but may involve distribution of body fat mass and decreased muscle tone as contributing factors [26]. The relationship between respiratory pattern disorders and facial development is popular but controversial at best. One group considers breathing pattern an important factor contributing to the long face syndrome (LFS) while the other group believes LFS has a genetic factor, and the breathing pattern may aggravate the condition rather than cause it [27]. Alternatively, others assert that lack of normal development of craniofacial respiratory apparatus may lead to deficiencies in growth and development of maxilla and mandible and may be manifested as hypoplasia in one or both of the jaws leading to significant malocclusion [1, 28]. In advanced cases, suboptimal airway volume may manifest in a multifaceted sleep disorder such as the OSAS. Effects of orthodontically motivated teeth extraction on resolving OSAS remain controversial, with defenders and detractors passionately arguing their positions. Whatever the influence, recording a baseline of clinical signs and symptoms, as well as radiographic measurements of the dimensions of the oropharyngeal airway, will aid in progressive evaluation of the positive or negative influence of the treatment.

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Airway volume, shape, compactness, and uniformity are significantly influenced by age and gender [29]. The upper airway space can be described in terms of height, width, depth, and volume. Presurgical evaluation of the airway will require software capable of utilizing manual input or automatic mapping of the outlines of the airway, as well as providing calculations of the volumetric capacity of the mapped area. CBCT scans and primary or tertiary software programs are providing effortless means to obtain an approximate numeric value. The challenge remains that the numeric values may differ from one software program to the next. As a result, consistency is achieved by only utilizing the same software program for evaluations performed over time. Breathing disorders of the young and the adult populations may be the result of constriction of the nasal passage, narrow or obstructed nasopharynx and/or oropharynx, hypertrophic nasal membranes, enlarged turbinates, hypertrophic palatine or pharyngeal tonsils, prominent nasal septal deviation, choanal atresia, as well as conditions such as tumors of the nasal cavity and the nasopharynx [27]. Pharyngeal tonsillar enlargement will diminish the volume of the nasopharyngeal airway in direct proportion to the degree of enlargement of the tonsil. Similarly, diminished mediolateral measurements of the oropharyngeal airway may be the result of bilateral enlargement of the palatine tonsils. In children and adolescent patients, these findings are not uncommon and are considered self-limiting. The same condition in the adult population, or unilateral enlargement of the tonsils in children, adolescent, or adult population should prompt further vigorous evaluation and possible treatment. Studies using CBCT scans have correlated a relationship between airway space and orofacial patterns. While not universally accepted, it has been reported that the oropharyngeal airway space of subjects with class III anteroposterior (AP) skeletal pattern appear to be wider and more flattened, therefore displaying a greater vertical orientation compared to the sagittal plane. Individuals with Class II AP skeletal pattern, on the other hand, showed a more anterior superior airspace. Abramson et al. [29] also evaluated the variations of the shapes of the pharynx and argued that with age the airway space becomes wider in the transverse direction and therefore more elliptical. Unlike non-OSAS individuals who exhibited a more rounded or square shaped airway, the airway space in patients with OSAS appears to be more elliptical or concave [27]. OSAS is accompanied with, or as a result of, the collapse of the oropharyngeal airway space, resulting in repeated episodes of air passage obstruction, decreased oxygen saturation and sleep disruption [27]. The narrowing of the oropharyngeal airway is commonly noted in the retroglossal and retropalatal regions [26]. There is a close relationship between soft-tissue walls of the oropharynx and the skeletal

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology

framework. It is this relationship that ultimately determines the location of the constriction [26]. In addition to the tonsillar tissues, the soft palate, uvula, and tongue are other soft-­ tissue structures of importance which may influence the narrowing of the airways [26]. The AP constriction of the pharyngeal airway as a result of hypertrophy of the pharyngeal tonsillar tissue is best viewed in the sagittal view. The coronal view, however, exquisitely highlights the hypertrophy of the palatine tonsillar tissues. Once the location of the constriction is detected, the axial view can be used to make linear measurements in the constricted areas. Alternatively, software generated calculations of the airway volume may be recorded for immediate or future evaluations. It is important to note that SDB is best manifested when the patient is in the supine position. When the patient is scanned in a sitting or standing position, the effect of the gravitational forces on the soft tissues cannot be accurately determined [30]. Scans acquired in sitting or standing position can only suggest presence of airway space constriction, from which a somewhat logical extrapolation may allow placing the patient in a higher risk category for further narrowing due to gravitational forces when the patient is in supine position. Since CBCT scans cannot be used to diagnose sleeping disorders, referral for further testing such as polysomnography is suggested [31, 32].

Tonsilloliths Other incidental pathology of the maxillofacial region may include incidental findings in the pharyngeal and palatine tonsils. Prominent or numerous calcifications of the tonsils should be identified and shared with the patient as incidental findings. Although, generally they are asymptomatic, when tissues around them are inflamed, they may result in difficulty with swallowing and varying degrees of halitosis. Detection of symptomatic tonsilloliths is important prior to any periodontal or oral surgery as comorbidities are known to prolong the treatment time for dental patients.

TMJ Evaluation Temporomandibular joint evaluation is an integral part of the craniofacial assessment. This gains greater significance when a patient is being worked up for SFOT and/or orthognathic surgery (OGS). Temporomandibular joints are growth centers during the craniofacial development. Later, they help stabilize the occlusion. Frequently, occlusal discrepancies have TMJrelated etiologies and hence a thorough evaluation of the TMJ complex (bilaterally) should be performed to rule out any temporomandibular disorders. Figures 7 and 8 show the TMJ

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displayed via CBCT demonstrating Idiopathic Juvenile Arthritis in a 30-year-old female who had prior orthodontics but developed anterior open bite several years after the completion of treatment due to condylar degeneration. The patient is undergoing additional orthodontic therapy with the goal to minimize trauma to the joints, stabilize her joint health, and move teeth to correct the anterior open bite.

Analysis Phase Diagnosis of the problem at hand remains the most important step in patient care. It, singularly, determines the subsequent steps, be it types of additional diagnostic tests, or the required treatment procedures. Analysis starts with the broad generalization of the condition(s) presented by the patient. These may be categorized as (1) missing tissue or anatomy (defect), (2) deformity or dysmorphology (in which structures are present but compared to normal, are too small, large or deformed), (3) anatomic malrelationships (in which the correct anatomy is present, but structures are in the wrong location), (4) or a combination of these [10]. When possible, the second step in the analysis of 3D imaging is to reach a specific or a broad diagnosis for the abnormality present. This assists with the degree, location, as well as the magnitude of the correction required. In a facially prioritized approach, relationships at (1) teeth to teeth, (2) teeth to jaws, (3) jaw to jaw, and (4) jaws to face are of utmost importance [1]. Redefining teeth to teeth relationship remains the domain of orthodontics and restorative dentistry/prosthodontics. The teeth-to-jaw relationships commonly present with inadequate existing dentoalveolar bone volume [1], which its prominence can be determined and mapped in pretreatment evaluations. Prior to treatment planning, the CBCT scan should be fully evaluated either by the surgical and clinical team, or by an oral maxillofacial radiologist, or alternatively a medical radiologist. In this chapter, we have set out to highlight some of the anatomic areas of significance, as well as common or incidental significant findings. This by no means is an exhaustive list. It is important to keep in mind that, reviewing the CBCT scans requires a thorough understanding of anatomy and the ability to apply that knowledge to sequential multiplanar views.

 ephalometric Analysis to Evaluate C the Craniofacial Relationships Tanna et  al. [33] outlined the objectives of cephalometric analysis as they serve to evaluate. 1. the relationship of maxilla to the cranium.

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Fig. 7  CBCT multiplanar along with 3D reconstructions showing the destruction of the left condyle (arrow) in a suspected case of idiopathic juvenile arthritis (IJA)

2. the relationship of mandible to the cranium. 3. the maxillomandibular relationship. 4. the relationship of dentition to maxilla. 5. the relationship of dentition to mandible. 6. the relationship of the entire complex and the soft tissue that drapes it. On any calibrated cephalometric radiograph, defining the planes (2D lines) and the angles associated with them are used to evaluate the craniofacial complex (Fig. 9). 2D cephalometric radiography presents with unique limitations, especially in the transverse dimension. Although PA cephalograms (Fig.  10) have been used traditionally for the transverse measurements, these measurements have errors due to ­ patient positioning, magnification, and superimpositions of other bony structures. Over the years, the PA cephalometric tracings have been discontinued and the information is

obtained from 3D imaging (CBCT) which is considered more reliable. 2D vs 3D cephalometric evaluations: Although 2D lateral cephalometric and PA cephalometric evaluations have merit, in the context of 3D diagnosis and determination of craniofacial needs, their value is very limited. Even though the transverse dimension is captured in the PA skull, it is associated with errors and magnification issues. Hence CBCT becomes a valuable tool in the determination of the phenotype and the craniofacial assessment in addition to ruling out any incidental pathology that may hamper the treatment plan (Fig. 11).

Treatment Planning Phase Taking into account, the information gleaned during the analysis phase, in the planning phase, a step-by-step plan to

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology

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Fig. 8  CBCT multiplanar along with 3D reconstructions showing the destruction of the right condyle (arrow) in a suspected case of idiopathic juvenile arthritis (IJA)

Fig. 9  Digital lateral cephalometric radiograph. Although used commonly for orthodontic cephalometric analysis, there is a move towards replacing the 2D with 3D cephalometric analysis for accuracy of transverse measurements via 3D cephalometric analysis

address the problems and abnormalities identified previously is created. The range of the treatment procedures considered may include reconstruction of missing tissues, as well as movement or repositioning of anatomic structures, etc. [10, 34]. The CBCT DICOM data, with the use of specialized software programs allow virtual surgical and non-surgical treatment planning, as well as virtual determination of the proper orientation of various anatomic structures. To this point, printing of guides and models from the 3D data set allows for in-depth understanding of the surgical or treatment area long before the patient returns for treatment. Practicing the proposed treatment virtually can highlight the anatomic, spatial, or esthetic challenges which may be encountered prior to patient involvement. Relationships between different anatomic structures such as the nerves, teeth, sinus cavities, location of the teeth within the alveolar ridges, as well as the potential post-treatment complications such as the positioning of the teeth outside the osseous housing of the alveolar ridges can be easily assessed [35]. Additionally, virtual treatment allows several different scenarios or surgical options to be practiced in advance in the digital world, with the option of comparing the outcome of the different strategies prior to patient involvement. The

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results can then be analyzed and the most appropriate solution for each patient selected. In essence, one of the most important advantages of 3D imaging is its ability to allow patient specific treatment planning and evaluation [30, 36].

 ocumenting Existing Periodontal Phenotype D Using CBCT

Fig. 10  Digitally acquired PA skull view. Craniofacial structures are superimposed. Used in planar cephalometry for transverse skeletal analysis

Prior studies [37] looked into the gingival phenotype and eventually the supporting alveolar bone thickness via CBCT and determined that there was moderate correlation between mandibular gingival thickness and the sagittal craniofacial profile. The authors found that in patients with concave craniofacial profile, smaller keratinized gingival width and gingival thickness were noted in the esthetic zone [37]. This is important in the selection process as documentation of existing phenotype is crucial for the selection of graft sites and eventual surgical planning and orthodontic tooth movement (Fig. 12). Gingival phenotype with adequate attached gingiva signals the adequacy of cortical bone that can be appreciated radiographically. Lack of this keratinized zone may lead to depletion in periodontal health and may indicate phenotype modification therapy via bone grafting (PhMT-bone) for such a patient. PhMT-bone begins by grafting to enhance the thickness of the cortical bone and allow ease of tooth movement through the augmented bone volume for decompensa-

Fig. 11  Cephalometric analysis being done via automated software after the clinician has identified the anatomic landmarks

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology

Fig. 12  Intraoral photograph of a patient showing gingival phenotype with adequate attached gingiva which indirectly signals the adequacy of the cortical bone

tion purposes. Eventually, if an orthognathic surgery is deemed necessary, it can be added to the treatment plan before teeth can be moved via traditional orthodontics.

Dentoalveolar Bone Analysis CBCT scans allow evaluation of the images in different multiplanar views. Buccal and lingual cortical bone is typically evaluated in axial, in coronal views for the circumferential cortication, and in sagittal views for the crestal cortication. Since the surgical facilitation for orthodontics focusses more on the adequacy of bony housing, both buccal and lingual/ palatal cortical bone become very important observation points to determine the alveolar bone volume. Although volumetric measurements can be accomplished using 3D imaging software (which can also measure the amount of bone available or missing), for practical purposes, clinical and radiographic estimates suffice in their ability to predict the movement of teeth through that region. In addition, physical exam, clinical oral examination, patient’s general health, as well as radiographic examination all play a vital role in this assessment. Note the mandibular anterior root prominences and insufficient bone at the mid root position.

 uantification of “Lack of Sufficient Bone” Via Q CBCT Analysis and General Plan to Graft Bone If the optimum treatment plan calls for moving the teeth facially, and subsequently outside the dentoalveolar bone volume, or if in 3D imaging presence of natural or iatrogenic dehiscences is noted, alternative approaches, including augmentation of the dentoalveolar bone should be considered. Augmentation of the area eliminates the restrictions posed

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Fig. 13  Three-dimensional reconstruction of CBCT data in a patient being evaluated for SFOT

by inadequate bony architecture [8]. Deficient or thin facial bone, especially in the anterior sextant is not an exception, rather the norm, and it must be considered carefully during the treatment planning phase (Fig. 13). Bone augmentation allows for tooth movement within an expanded osseous envelope, thereby creating an optimum architecture and bone phenotype [8]. Identification of the nature of the inadequacy and architecture of the alveolar ridge will assist in expanding the treatment planning options available. Therefore, advance determination of necessity for augmentation and hence changing the dentoalveolar bone phenotype allows for more accurate viable option to be considered. The ability to do so allows movement of the teeth into the grafted areas of the arches, thereby avoiding planned loss of teeth [11]. The decision to place bone graft is influenced by the direction and the amount of desired tooth movement, thickness of the alveolar bone, as well as the age of the patient. When 3D imaging shows bone thickness around the roots to be inadequate, grafting may be necessary. In the presence of fenestration and/or dehiscence around roots, lack of alveolar augmentation in the direction of tooth movement increases the risk of further post-treatment bone loss in an already thin alveolar region [8]. Understanding the degree of augmentation required; in other words, quantification of the degree of grafting necessary or that of the insufficient bone is better determined utilizing 3D imaging modalities such as CBCT. Although quantification implies the exact measurement of alveolar bone that houses the maxillary and mandibular teeth; many times, the thickness of the buccal cortical bone is a key factor in determination of this phenotypic expression. It is generally noted that if the buccal cortical bone is thin (Fig. 14), the movement of teeth through the alveolar bone becomes a challenge and unless surgically facilitated, orthodontic treatment would not be successful. It becomes even

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Fig. 14  CBCT data displayed in sagittal, axial, panoramic, and 3D reconstructions. In the orthogonal sections, note the significantly thinned buccal cortical bone of the left mandibular and maxillary canines

more challenging if there are significant skeletal malformations leading to anterior or posterior open bite, deep bite, or cross-bite. Generally, if the diagnosis is made appropriately, then the follow-up surgical plan may include grafting as well as orthognathic surgery before initiating orthodontic tooth movement. Inadequate osseous housing of the teeth becomes a crucial consideration especially if the patient has significant dentofacial deformities [38].

I mbrication of Teeth and Radiographic Assessment of Alveolar Bone Thickness Space appropriation of the teeth is critical in the final success of the orthodontic treatment. Dental crowding is commonly an arch length deficiency which may result in general or focal dentoalveolar bone deficiency. Evaluation of the deficiencies in the osseous thickness of the buccal (most commonly) and lingual (less commonly) is important in the pretreatment evaluation [11]. Deficient alveolar bone thickness may limit treatment options and necessitate extractions to balance the existing teeth within the arch width available [11]. They may result in dehiscences and fenestrations, which can limit the extent to which teeth can be safely moved orthodontically [11]. The decision to perform corticotomy on the buccal/facial and/or lingual/palatal cortical bone plates, in order to aid the

process of teeth movement, generally depends on the desired speed and distance in which teeth are moved [8]. If the alveolar bone thickness is sufficient, solitary perforations in the alveolar ridge, over the radicular surface may be placed [8]. However, if the 3D scans show less than 1–2 mm thickness of buccal/facial bone, these perforations are omitted, in order to ensure the integrity of the radicular surface [8]. Alternatively, when thick dentoalveolar bone is present, mild corticotomy surgery may not produce enough injury to appreciably expedite tooth movement [8]. As such linear measurement of the cortical bone is of utmost importance. The maxillary and mandibular anterior teeth as well as the maxillary premolars have naturally thinner facial/buccal cortical plates [39, 40]. Iatrogenic creation of significant tooth inclination may also exacerbate the thinness of the buccal/ facial osseous root coverage. The buccal/facial bone thickness is measured from the outer border of the cortical plate to the outer border of the root’s cementum. While at the root level, this measurement can be performed in any of the multiplanar views, in CBCT images, the sagittal view provides the best representation of the osseous thickness. CBCT allows for near accurate and reliable linear measurements of dental and bone structures [41, 42]. The accuracy of the reformatted CBCT images is known to be affected by scanner parameters such as spatial resolution, presence of scatter, image quality, voxel size, kV, mA, number of basis

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology

images, dimensions of the field of view (FOV), as well as the acquisition and reconstruction software utilized [42]. Scanners with higher spatial resolution, smaller voxel sizes, and small FOV, produce greater accuracy in regard to linear measurement. The differences between the actual and CBCT measurements were small and not statistically significant, and as such not clinically relevant [41]. However, choice of the degree of accuracy needed remains strongly tied to the procedure of interest. While high-­ resolution scans provide greater linear measurement accuracy, the degree of radiation exposure to the patient renders them unfeasible for large scans required for SFOT surgeries. With high-resolution large scans, the minimal increase in accuracy gained does not justify the significantly increased radiation dose to the patient. For surgeries such as the SFOT, it is far more advantageous to have the entire surgical field in one scan, at a lower dose to the patient, even if that translates into a small compromise in the final but clinically unimportant variation in measurements. Therefore, care must be taken to balance the appropriate degree of radiation exposure to the patient, while extracting the maximum amount of information from the CBCT scans acquired [43, 44]. In a CBCT scan without significant artifacts, linear measurements made over small distances have shown to be accurate within 0.1 to 0.2 mm [45]. It is important to note that linear measurements over long distances are considered to be less accurate. This latter limitation however does not apply to this conversation and will not be pursued further in this chapter. CBCT is slightly more reliable for linear measurements than computer tomography (CT). Considering the significant less radiation dose to the patient, this is good news for both the dental practitioners and patients, who can take advantage of the greater accuracy with less radiation [46].

Artifacts No discussion about CBCT imaging is complete, without referencing common limitations. Artifacts of one sort or another are present in almost all scans acquired. They have the potential to adversely affect the quality of a CBCT image. Presence of metallic containing restorations, implant fixtures, or orthodontic armamentarium produce streak artifacts [45] which can extend far beyond the point of origin, therefore blurring or completely concealing the area of interest. Another artifact frequently encountered is patient movement during image acquisition. Decreasing scan time, use of straps and strict guidelines given to the patient prior to image acquisition may reduce patient movement [47]. Scatter noise, another common artifact, is greater in scans with larger FOVs. To best protect the patient from the potential harmful effects of radiation-based imaging and simultaneously decrease scatter noise artifact, the smallest FOV

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containing the region of interest should be used. This allows for an image with a higher spatial resolution while at the same time reducing the scatter noise, providing a better quality image [45]. Due to the adverse effects of artifacts, caution should be exercised, when performing measurements or evaluations of the anatomic structures and boundaries in the affected areas [48]. It is important to note that the list of artifacts mentioned above is neither complete nor exhaustive.

Post-treatment Evaluation Volumetric analysis of post grafting scans and post orthognathic surgery (OGS) scans: Just as important as the pre-SFOT scan interpretation is, the post-SFOT and post-OGS are equally important in terms of analysis to ensure that the expected outcomes have been achieved, and the treatment plan is on track. Post-SFOT scans will show the amount of bone enhancement via CBCT especially on the buccal aspect where the presurgical thin buccal cortical plate would have limited the amount of tooth movement. The added bone via grafting gives the clinician the added comfort to move teeth post-surgical facilitation, without the fear of moving the teeth outside the bony housing. It transitions to a better planning for orthognathic surgery. Post orthognathic surgery, the orthodontic therapy is continued to achieve the optimum esthetics and occlusal stability as planned.

Conclusion The interdisciplinary nature of SFOT demands extensive communication between the surgeon, the restorative dentist, other specialties, and lab technicians involved. Incorporating 3D CBCT imaging into the virtual planning allows assessment of the existing anatomy in order to plan the appropriate orthodontic and surgical treatment course to achieve functionally stable and esthetically pleasing outcome. 2D analysis lacks the in-depth ability required to ascertain current location of the teeth within, and the ability to predict the future position of the teeth with respect to the alveolar process. In addition to providing in-depth 3D presurgical information, CBCT imaging provides the means to assess hard tissue changes which occur during tooth movement [11]. Regardless of who evaluates the CBCT scans, there are a number of principles which should be followed for all 3D scans reviewed, and by everyone who attempts their hand at reviewing the scans. The entire volume should be reviewed in full. It is important that a systematic approach is taken in which every structure visible within the scan is evaluated. Significant and important incidental findings should be noted

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and discussed with the patient. This presupposes that the person reviewing the images is sufficiently trained to interpret the complexity of 3D images. As with the various dental practitioners and the dental laboratory technicians; the oral maxillofacial radiologist is also an integral member of the team, providing initial preand post-surgical comparative analyses. (S)he will assist in comprehensive radiographic diagnosis of the craniofacial deficiencies or anatomic variations with potential to complicate the surgical procedure.

References 1. Mandelaris GA, Neiva R, Chambrone L. Cone-beam tomography and interdisciplinary dentofacial therapy an american academy of periodontology best evidence review focusing on risk assessment of the dentoalveolar bone changes influenced by tooth movement. J Periodontol. 2017;88(10):960–77. 2. Spear FM, Kokich VG, Mathews DP. Interdisciplinary management of anterior dental esthetics. J Am Dent Assoc. 2006;137(2):160–9. 3. Jivraj S, Corrado P, Chee W. An interdisciplinary approach to treatment planning in implant dentistry. Br Dent J. 2007;202(1):11–7. 4. Mandelaris GA, DeGroot BS, Relle R, Shah B, Huang I, Vence BS.  Surgically facilitated orthodontic therapy: optimizing dentoalveolar bone and space appropriation for facially prioritized interdisciplinary dentofacial therapy. Compend Contin Educ Dent. 2018;39(3):146–56. 5. Proffit WR, Fields HW, Larson B, Sarver D. Contemporary orthodontics. 4th ed. MOsby: St. Louis, MO; 2006. 6. Rose JC, Roblee RD.  Origins of dental crowding and malocclusions: an anthropological perspective. Compend Contin Educ Dent. 2009;30(5):292–300. 7. McNamara JA.  Maxillary transverse deficiency. Am J Orthod Dentofac Orthop. 2000;117(5):567–70. 8. Zimmo N, Saleh MHA, Mandelaris GA, Chan H-L, Wang H-L.  Corticotomy-accelerated orthodontics: a comprehensive review and update. Compend Contin Educ Dent. 2017;38(1):17–25. 9. Kaley J, Phillips C. Factors related to root resorption in edgewise practice. Angle Orthod. 1991;61(2):125–32. 10. Steinbacher DM. Three-dimensional analysis and surgical planning in craniomaxillofacial surgery. J Oral Maxillofac Surg. 2015;73(12 Suppl):S40–56. 11. Mandelaris GA, Scheyer ET, Evans M, Kim D, McAllister B, Nevins ML, et al. American academy of periodontology best evidence consensus statement on selected oral applications for cone-­ beam computed tomography. J Periodontol. 2017;88(10):939–45. 12. Mandelaris GA, Huang I, Relle R, Vence BS, DeGroot BS.  Surgically facilitated orthodontic therapy (SFOT): diagnosis and indications in interdisciplinary dentofacial therapy involving tooth movement. Clin Adv Periodontics. 2020;10(4):204–12. 13. Syed AZ, Zahedpasha S, Rathore SA, Mupparapu M. Evaluation of canalis basilaris medianus using cone-beam computed tomography. Imaging Sci Dent. 2016;46(2):141–4. 14. Singer SR, Kim IH, Creanga AG, Mupparapu M. Physiologic and pathologic calcifications of head and neck significant to the dentist. Dent Clin N Am. 2021;65(3):555–77. 15. Vogiatzi T, Kloukos D, Scarfe WC, Bornstein MM.  Incidence of anatomical variations and disease of the maxillary sinuses as identified by cone beam computed tomography: a systematic review. Int J Oral Maxillofac Implants. 2014;29(6):1301–14.

M. Sadrameli et al. 16. Rege ICC, Sousa TO, Leles CR, Mendonça EF. Occurrence of maxillary sinus abnormalities detected by cone beam CT in asymptomatic patients. BMC Oral Health. 2012;12:30. 17. Yeung AWK, Tanaka R, Khong P-L, Arx T, Bornstein MM.  Frequency, location, and association with dental pathology of mucous retention cysts in the maxillary sinus. A radiographic study using cone beam computed tomography (CBCT). Clin Oral Investig. 2018;22(3):1175–83. 18. Moskow BS. A histomorphologic study of the effects of periodontal inflammation on the maxillary sinus mucosa. J Periodontol. 1992;63(8):674–81. 19. Hauman CHJ, Chandler NP, Tong DC. Endodontic implications of the maxillary sinus: a review. Int Endod J. 2002;35(2):127–41. 20. Nascimento EHL, Pontual MLA, Pontual AA, Freitas DQ, Perez DEC, Ramos-Perez FMM. Association between odontogenic conditions and maxillary sinus disease: a study using cone-beam computed tomography. J Endod. 2016;42(10):1509–15. 21. Dispenza C, Saraniti C, Caramanna C, Dispenza F.  Endoscopic treatment of maxillary sinus mucocele. Acta Otorhinolaryngol Ital. 2004;24(5):292–6. 22. Derinkuyu BE, Boyunaga O, Oztunali C, Alimli AG, Ucar M.  Pterygopalatine fossa: not a mystery! Can Assoc Radiol J. 2017;68(2):122–30. 23. Cappello ZJ, Potts KL. Anatomy, Pterygopalatine Fossa. StatPearls. Treasure Island, FL: StatPearls Publishing. Copyright © 2021, StatPearls Publishing LLC; 2021. 24. Frunza A, Slavescu D, Lascar I.  Perineural invasion in head and neck cancers - a review. J Med Life. 2014;7(2):121–3. 25. Li H-Y, Chen N-H, Wang C-R, Shu Y-H, Wang P-C.  Use of 3-dimensional computed tomography scan to evaluate upper airway patency for patients undergoing sleep-disordered breathing surgery. Otolaryngol Head Neck Surg. 2003;129(4):336–42. 26. Schellenberg JB, Maislin G, Schwab RJ. Physical findings and the risk for obstructive sleep apnea. The importance of oropharyngeal structures. Am J Respir Crit Care Med. 2000;162(2 Pt 1):740–8. 27. Zinsly SR, Moraes LC, Moura P, Ursi W. Assessment of pharyngeal airway space using cone-beam computed tomography. Dental Press J Orthodont. 2010;15:150–8. 28. Chiang CC, Jeffres MN, Miller A, Hatcher DC. Three-dimensional airway evaluation in 387 subjects from one university orthodontic clinic using cone-beam computed tomogoraphy. Angle Orthod. 2012;00(0):1–8. 29. Abramson ZR, Susarla S, Tagoni JR, Koban L. Three-Dimensional computed tomographic analysis of airway anatomy. J Oral Maxillofac Surg. 2010;68:363–71. 30. Kim WY, Hong S-N, Yang SK, Nam KJ, Lim KH, Hwang SJ, et al. The effect of body position on airway patency in obstructive sleep apnea: CT imaging analysis. Sleep Breath. 2019;23(3):911–6. 31. Rundo JV.  Obstructive sleep apnea basics. Cleve Clin J Med. 2019;86:2–9. 32. Malhotra RK, Kirsch DB, Kristo DA, Olson EJ, Aurora RN, Carden KA, et  al. Polysomnography for obstructive sleep apnea should include arousal-based scoring: an American academy of sleep medicine position statement. J Clin Sleep Med. 2018;14(7):1245–7. 33. Tanna NK, AlMuzaini AAAY, Mupparapu M. Imaging in orthodontics. Dent Clin N Am. 2021;65(3):623–41. 34. Bobek S, Farrell B, Choi C, Farrell B, Weimer K, Tucker M. Virtual surgical planning for orthognathic surgery using digital data transfer and an intraoral fiducial marker: the charlotte method. J Oral Maxillofac Surg. 2015;73(6):1143–58. 35. Elnagar MH, Aronovich S, Kusnoto B. Digital workflow for combined orthodontics and orthognathic surgery. Oral Maxillofac Surg Clin North Am. 2020;32(1):1–14. 36. Xia J, Ip HH, Samman N, Wang D, Kot CS, Yeung RW, et  al. Computer-assisted three-dimensional surgical planning and

Role of Oral and Maxillofacial Radiologist in Contemporary Interdisciplinary Dentofacial Therapy Utilizing CBCT Technology simulation: 3D virtual osteotomy. Int J Oral Maxillofac Surg. 2000;29(1):11–7. 37. Cha S, Lee SM, Zhang C, Tan Z, Zhao Q.  Correlation between gingival phenotype in the aesthetic zone and craniofacial profile-a CBCT-based study. Clin Oral Investig. 2021;25(3):1363–74. 38. Posnick JC, Mandelaris GA, Tremont TJ.  Orthodontic trends in the treatment of dentofacial deformities. J Oral Maxillofac Surg. 2021;79(3):518–9. 39. Araújo MG, Silva JCCD, Medonça AFD, Lindhe J. Ridge alterations following grafting of fresh extraction sockets in man. A randomized clinical trial. Clin Oral Imp Res. 2015;26(4):407–12. 40. Ghassemian M, Nowzari H, Lajolo C, Verdugo F, Pirronti T, D’Addona A.  The thickness of facial alveolar bone overlying healthy maxillary anterior teeth. J Periodontol. 2021;83(2):187–97. 41. Sherrard JF, Rossouw E, Benson BW, Carrillo R. Accuracy and reliability of tooth and root lengths measured on cone-beam computed tomographs. Am J Orthod Dentofac Orthop. 2010;137:S100–8. 42. Porto OCL, Silva BSDF, Silva JA, Estrela CRDA, Alencar AHGD, Bueno MDR, et  al. CBCT assessment of bone thickness in maxillary and mandibular teeth: an anatomic study. J Appl Oral Sci. 2020;28(e20190148, eCollection 2020.). 43. Ludlow JB, Timothy R, Walker C, Hunter R, Benavides E, Samuelson DB, et  al. Effective dose of dental CBCT-a

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meta analysis of published data and additional data for nine CBCT units. Dentomaxillofac Radiol. 2015;44(1):20140197. https://doi.org/10.1259/dmfr.20140197. 44. Lofthag-Hansen S, Thilander-Klang A, Gröndahl K.  Evaluation of subjective image quality in relation to diagnostic task for cone beam computed tomography with different fields of view. Eur J Radiol. 2011;80(2):483–8. 45. Hilgers ML, Scarfe WC, Scheetz JP, Farman AG. Accuracy of linear temporomandibular joint measurements with cone beam computed tomography and digital cephalometric radiography. Am J Orthod Dentofacial Orthop. 2005;128(6):803–11. 46. Kim S, Yoshizumi TT, Toncheva G, Yoo S, Yin F-F. Comparison of radiation doses between cone beam CT and multi detector CT: TLD measurements. Radiat Prot Dosimetry. 2008;132(3):339–45. 47. Spin-Neto R, Wenzel A. Patient movement and motion artefacts in cone beam computed tomography of the dentomaxillofacial region: a systematic literature review. Oral Surg Oral Med Oral Pathol Oral Radiol. 2016;121(4):425–33. 48. Oliveira ML, Candemil AP, Freitas DQ, Haiter-Neto F, Wenzel A, Spin-Neto R.  Objective assessment of the combined effect of exomass-related- and motion artefacts in cone beam CT.  Dentomaxillofac Radiol. 2021;50(1):20200255. https://doi.org/10.1259/dmfr.20200255.

Assessing the Temporomandibular Joint Condition in Surgically Facilitated Orthodontic Treatment planning James McKee

Introduction Assessing the structure and condition of the temporomandibular (TM) joint complex is an integral component of treatment planning process when considering surgical facilitated orthodontic therapy (SFOT) for interdisciplinary dentofacial therapy (IDT) patient care (Figs. 1, 2, 3, 4, 5 and 6). Changes in the condition of the TM joint can result in many of the clinical scenarios that may require SFOT to correct. Malocclusion traits that have been associated with structural changes in the TM joints include excessive overjet, anterior open bites, compromised overbite, crowding, posterior crossbite patterns, and dolichocephalic facial growth patterns [1]. TM joint condition can also have a significant impact on the occlusion at the tooth level [2]. The interdisciplinary team, led by the restorative dentist/prosthodontist, must understand the condition of the TM joints to assess the potential stability of the occlusion obtained through IDT treatment involving SFOT.

Normal TM Joints

ment. Hinging movements take place in the lower compartment, and gliding movements take place in the upper compartment [3]. The superior surface of the disk fits into the inferior cranial contour (i.e., glenoid fossa), while the inferior surface is concave to fit against the contours of the mandibular condyle. The disk is thick, round to oval and divided

Fig. 1  Pre op ant

In normal TM joints, the articular disk is a biconcave fibrocartilaginous structure located between the mandibular condyle and the temporal bone component of the cranium (Figs.  7 and 8). It functions to accommodate a hinging action (rotation) as well as the gliding actions (translation) between the temporal and articulating aspect of the mandible (i.e., condyle). The articular disk is a roughly oval, firm, fibrous plate with its long axis being transversely directed. It is shaped like a peaked cap that divides the joint into a larger upper compartment and a smaller lower compart-

J. McKee (*) Private Practice, Downers Grove, Illinois/Spear Education Center (Scottsdale, AZ), Downers Grove, IL, USA e-mail: [email protected]

Fig. 2  Pre op mand

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_9

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Fig. 3  Pre op max

Fig. 4  Post op ant

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Fig. 6  Pre op max

Anterior

Posterior

Fig. 7   MRI sagittal

Fig. 5  Post op mand

into an anterior band (of approximately 2  mm in thickness), a posterior band (approximately 3  mm in thickness), with the central intermediate band (nearly 1 mm in thickness). The disk is attached all around the joint capsule except for the ligamentous attachments that fix the

disk directly to the medial and lateral condylar poles. These ligamentous attachments ensure that the disk and condyle move together in mandibular movements. The anterior extension of the disk is attached to a fibrous capsule superiorly and inferiorly. The disc has an insertion to the lateral pterygoid muscle where the fibrous capsule is lacking, and the synovial membrane is supported only by loose areolar tissue. The anterior and posterior bands have predominantly transversal oriented fibers, while the thin intermediate zone has antero-posteriorly oriented fibers. Posteriorly, the bilaminar region consists of two layers of fibers separated by loose connective tissue. The upper layer or temporal lamina is composed of elastin and is attached to the post-glenoid process, medially extended ridge, which is the true posterior boundary of the joint. It prevents slipping of the disk with mandibular movements (opening). The inferior layer of the fibers or inferior lamina curve down behind the condyle to fuse with the cap-

Assessing the Temporomandibular Joint Condition in Surgically Facilitated Orthodontic Treatment planning

Lateral

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Medial

Fig. 8   MRI coronal

sule and back of the condylar neck at the lowest limit of the joint space. It prevents excessive rotation of the disk over the condyle [3, 4] (Fig. 9). Disk position in TM joints that are not structurally altered (otherwise considered anatomically ideal) was initially assessed in the vertical plane. Drace [5] discussed a 12:00  ±  10° definition of normal. Rammelsberg [6] later suggested a 12:00  ±  30° definition of normal. Clarity of normal disk position was significantly improved with Provenzano’s [7] study which defined the normal disk position as an 11:00 o’clock intermediate position which corresponds to the load bearing capabilities of normal disk tissue. Using an 11:00 o’clock intermediate position as a “normal” anatomic reference helps define a 1:00 “normal” posterior disk attachment. This is a more logical assumption since the disk will cover the condyle in all mandibular movements. In normal joints, the condyle is an ovoid process seated atop a narrow condylar process of the mandible. It’s length is 15 to 20 mm (medial to lateral dimension) and 8 to 10 mm (anterior posterior dimension) (Figs. 10 and 11). The lateral pole of the condyle is rough, bluntly pointed, and projects only moderately from the plane of ramus, while the medial pole extends sharply inward from this plane. The articular surface lies on its anterosuperior aspect, thus facing the posterior slope of the articular eminence of the temporal bone. The condyle should be in the middle of the joint socket as opposed to having an anterior or posterior position in the joint socket [3].

Fig. 9   Piper 1–2

Anterior

Posterior

Fig. 10   CBCT sagittal

Piper [8] outlined the following characteristics of structurally intact TM joints: • The disc maintains a biconcave shape in the sagittal perspective.

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Lateral

Medial

Fig. 11   CBCT coronal

• The disc is aligned at 1:00 o’clock at both poles in fully seated condylar position. • The disc centers the condyle in the articular fossa in the sagittal plane. • The disc is thicker in the mid apex in the coronal plane. • The bearing zone of the disc deflects the condyle inferior from the fossa by approximately 2 mm. • The disc and the shape of the fossa center the mandibular condyle in the transverse plane. • The sagittal condyle to fossa ratio is 60–66%. • The condyle is 8 ± 1 mm in length, 20 ± 2 mm in width, and 120 mm2 in axial surface area. • The condyle is convexly shaped in all perspectives. • The growing condyle does not show a distinct cortex. • The mature condyle should have cortex between 1 and 1.5 mm in thickness. • The articular fossa is concave in all perspectives. • The articular eminence is convex in all perspectives. • The condyle remains interposed between the apex of the condyle and the fossa in all postures. Normal TM joints will typically foster mandibular growth exhibiting the patients full genetic potential. While SFOT may be necessary in these types of jaw joints, it is more likely that SFOT may be considered in structurally altered TM joints because a malocclusion is being corrected orthodontically. TM joints can be classified using one of three different systems. The Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) [9] emphasizes pain disorders. The Wilkes Classification System [10] emphasizes TM joint surgery. The Piper Classification System [8] emphasizes restorative and orthodontic treatment. As a result, most restorative dentists will classify TM joints using the Piper Classification System.

Fig. 12   Piper 3A–3B

Normal TM joints are classified as Piper Stage 1. Piper Stage 2 TM joints have beginning lateral pole laxity. Both of these stages have a high level of predictability for occlusal stability [8].

Structurally Altered TM Joints Structurally altered TM joints are typically expressed via tears in the lateral ligament, medial ligament, or both the lateral and medial ligament tears. When the ligament tears, the disk displaces anteriorly. The condyle can move under the disk in a translated position (disk displacement with reduction) or the condyle and/or disk may change shape so that the condyle does not move under the disk in a translated position (disk displacement without reduction) [8]. If the ligament tears at the lateral pole, and the disk can move under the disk in a translated position (disk displacement with reduction). This type of joint is referred to as a Piper Stage 3A. If the ligament tears at the lateral pole and, the disk cannot move under the disk in a translated position (disk displacement without reduction). This type of joint is referred to as a Piper Stage 3B (Fig. 12) [8]. If the ligament tears at the medial pole, and the disk can move under the disk in a translated position (disk displacement with reduction). This type of joint is referred to as a Piper Stage 4A. If the ligament tears at the medial pole, and the disk cannot move under the disk in a translated position

Assessing the Temporomandibular Joint Condition in Surgically Facilitated Orthodontic Treatment planning

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Fig. 13   Piper 4A–5B

(disk displacement without reduction). This type of joint is referred to as a Piper Stage 4B [8]. If the disk is displaced without reduction, the condylar may move through the soft tissue filling the disk area. If this joint is painful, it is staged as a Piper 5A joints. If this type of joint is not painful, the joint is staged as a 5B joint (Fig. 13) [8]. The medial aspect of the TM joints plays several key roles. The disk at the medial pole positions the condyle in the joint socket to foster a repeatable condylar position. The disk at the medial pole also maintains the vertical dimension at the TM joint. The vertical dimension can grow to its full genetic potential if the disk covers the condyle. The vertical dimension can either increase or decrease based upon changes in the TM joint [7].

 he Impact of Disk Displacements T in the Growing Patient The disk plays a vital role in growth and development. If normal disk position is altered during the growing years, there is an increased risk for altered growth and development. Figure  14 demonstrates a clinical example of a structurally altered condyle in a 17-year-old female [8– 21]. The assumption was that structurally altered TM joints primarily influenced mandibular growth. This assumption has been revised due to clinical observation and research. A more ­contemporary position in the profession is that structural changes at the joint level in Piper 4A-5B patients can result not only in a reduction of mandibular growth and development but also maxillary growth and development and [17, 20, 22].

Fig. 14  Mary 17YO

Many patients who require surgically facilitated orthodontic treatment have constricted maxillary growth. Given the connection between structurally altered TM joints during growth and the reduction in mandibular and maxillary growth, it would be prudent to perform a complete joint evaluation on patients who are considering IDT involving SFOT.

TM Joint Evaluation There are 6 aspects to a TM joint clinical screening exam. The exam techniques in a TM joint screening exam are indirect testing methods that are used to determine when it may be necessary to use direct testing methods such as MRI and CBCT. There is not typically a need to use direct visualization in Piper 1-3B patients due to the low to moderate risk levels associated with these joints. Conversely, Piper 4A-5B joint typically require imaging of the TM joint complex to assess the amount of soft and hart tissue changes [8].

 ey Aspects to the TM Joint Screening Exam K of a Patient History Intake from the Patient The first, and perhaps the most important, indirect testing methods used in the TM joint exam is the history intake.

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Obtaining an accurate and complete history is integral to evaluating TM joint condition. The history for TM joint evaluation is comprised of four parts. The first part is the joint

Occlusal/facial analysis

Doppler auscultaon

Inial point of contact (FSCP) FSCP-MI shi (mm) Direcon

Translaon Rotaon Audible crepitus

Anterior tooth contact (FSCP) mm from contact Horizontal Vercal Upper anterior retroclined

Disk clicking/popping Opening Closing Previous click

L

Occlusal classificaon (FSCP) Right-molar Right-canine Le-molar Le-canine Retrognathia Maxillary Mandibular Facial asymmetry Right Le Load tesng Negave Posive-light Posive-moderate Posive-firm Difficult manipulaon

R

Headaches (0-3) Temple Front of the head Back of the head Neck Number of HA/week Aware of clenching Aware of grinding

R

L

Pain scales (0-10) Average Worst Modified diet due to pain

R

L

L

Muscle palpaon (0-3) Temporalis Masseter Medial pterygoid Lateral pterygoid Suprahyoids Infrahyoids Greater occipital Trapezius Mastoid SCM Previous treatment Splint Physical therapy Chiropracc Medicaons Orthodoncs Orthognathic surgery

Diagnosc nerve blocks

EX

# of appliances Current appliance Upper hard ramped Secure fit FSCP=MI Anterior guidance Age Last adjustment

Range of moon Max opening with pain Max opening without pain Right Le Protrusive Opening deviaon Working contacts Balancing contacts

Mandibular midline (FSCP) mm Direcon

Notes

R

history. This is a history that describes the condition of the jaw joint both currently and in the past.

R

L

Diagnosc nerve blocks Auriculotemporal block % pain decrease Carbocaine/marcaine Greater auricular block % pain decrease Carbocaine/marcaine Greater occipital block % pain decrease Carbocaine/marcaine

R

L

Joint posion analysis Vercal (mm from normal) Horizontal (mm from normal) Transverse (mm from normal)

R

L

Diagnosc records Mounted study models Digital photographs CBCT MRI Previous MRI Previous CBCT Sleep screening

TX

ICD orders 1.Migraine 2.Tension Headaches 3.Atypical facial pain 4.Headache-facial pain 5.Cervicalgia 6.Trigeminal Neuralgia 7.Effusion of Joint (Pain) 8.CRPS 9.Asepc/Avascular Necrosis 10.Osteochondrosis Unspecified 11.Ostechondropathy 12.Ankylosis of Joint 13.Arcular Carlage Disorder 14.Maxillary hypoplasia 15.Mandibular hypoplasia 16.Jaw-Development 17.Abnormal jaw closure 18.Limited mandibular range of moon 19.Deviaon in opening and closing the mandible 20.TMJ Disorder 21.TMJ- Pain/dysfuncon 22.Sleep related bruxism 23.Somatoform disorder 24.Tinnitus, Right Ear 25.Tinnitus, Le Ear 26.Tinnitus, Bilateral Ear 27.Tinnitus, Unspecified Ear 28.Otalgia, (earache) R 29.Otalgia, (earache) L 30.Otalgia, Bilateral 31.Otalgia, Unspecified Ear 32.Excessive horizontal overlap 33.Reverse arculaon 34.Insufficient interocclusal distance 35.Excess spacing of fully erupted teeth 36.Insufficient anterior guidance 37.Non-working side interference 38.Lack of post occlusal support 39.Open anterior occlusal relaonship 40.Closed anterior occlusal relaonship 41.Horizontal displacement of fully erupted teeth 42.Vercal displacement of full erupted teeth 43.Rotaon of fully erupted teeth 44.Excessive interocc distance of erupted teeth

G43.909 G44.209 G50.1 R51 M54.2 G50.0 M25.50 G90.5 M87.9 M92.9 M93.9 M26.61 M26.63 M26.02 M26.04 M27.0 M26.51 M26.52 M26.53 M26.69 M26.62 G47.63 F45.8 H93.11 H93.12 H93.13 H93.19 H92.01 H92.02 H92.03 H92.09 M26.23 M26.24 M26.36 M26.32 M26.54 M26.56 M26.57 M26.220 M26.221 M26.33 M26.34 M26.35 M26.37

Biggest issue

• Question: Do you have clicking or popping in joint currently? • If a patient presents with a clicking joint, it typically means there is a torn ligament attaching the disk to the condyle. The ligament attaching the disk to the lateral pole could be torn (Piper Stage 3A/3B) or the ligament attaching the disk to the medial pole could be torn (Piper 4A/4B/5A/5B). This would be referred to as an anteriorly displaced disk with reduction. • IF YES, THERE IS A MODERATE TO INCREASED CHANCE OF A PIPER 4A/4B/5A/5B JOINT BEING PRESENT WHICH WILL NECESSITATE IMAGING FOR DEFINITE CLASSIFICATION AND DIAGNOSIS. • Question: Has either joint clicked or popped in the past? • If a patient presents with a history of TM joint clicking but does not click now, typically the disk has changed shape and the condyle cannot move under the disk when

the condyle moves forward. This would be referred to as an anteriorly displaced disk without reduction. A disk that used to click but does not click currently typically indicates a long-standing injury to the joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Does either jaw lock when trying to open? • If a patient’s jaw is locking when trying to open, the disk is usually anteriorly displaced. In these joints, it is common for the disk to wedge in front of the condyle. As a result of the disk displacement, it is difficult for the condyle to move normally. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Has either jaw locked in the past? • If a patient’s jaw has locked in the past, it is common for the joint to have a long-standing injury that has changed

Assessing the Temporomandibular Joint Condition in Surgically Facilitated Orthodontic Treatment planning

the anatomy of both the soft tissue (disk) and hard tissue (condyle/joint socket). • IF YES,INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Do you remember having the problem in high school? • The earlier in life a patient notices a jaw joint problem, the greater the chance for advanced structural changes at the soft tissue (disk) and hard tissue (condyle/joint socket). • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: The second history is the history of previous treatment. • Have you ever had orthodontic treatment for a Class II occlusion (overbite/overjet)? • A common clinical presentation of Piper 4A/4B/5A/5B joints is a Class II occlusion. Manfredini [22] wrote in 2016 in his systematic review of literature that “it seems reasonable to suggest that skeletal Class II profiles and hyperdivergent growth patterns are likely associated with an increased frequency of TMJ disc displacement and degenerative disorders.” • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did you have any teeth extracted for orthodontic treatment? • Extractions for orthodontic treatment are usually recommended if there is no enough growth of the mandible and the maxilla to accommodate the normal number of teeth. In many of these cases, the reason the mandible and the maxilla did not grow normally is due to changes in the jaw joints. As Carlos Flores-Mir [20] wrote “TMJ disc abnormality was associated with reduced forward growth of the maxillary and mandibular bodies. TMJ disc abnormality was associated with reduced downward growth of the mandibular ramus. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did you have headgear during orthodontics? • Headgear typically retracts maxillary growth to allow for the mandible to “catch up.” The reality is many of these cases is that the mandible is unable to “catch up” because the disk is not covering the bone. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did you have an orthodontic appliance that moved your lower jaw forward?

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• Functional appliances, such as a Herbst appliance, advance the mandible with the hope that the condyle will grow and fill the space that was created when the mandible was advanced. In many patients, the reason the mandible required advancement was due to an early joint injury which displaced the disk and negatively impacted growth. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did your orthodontic treatment take longer than 2 years? • When orthodontic treatment requires more time than normal, it would be prudent to evaluate the amount of tooth movement required. In many of these cases, there is a severe Class II occlusion or a facial asymmetry that is the result of a disk displacement with altered growth. In these cases, it may take longer than normal to complete orthodontic treatment given the altered tooth position from altered growth. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have you ever had orthodontic treatment more than once? • Bite changes after orthodontic treatment can occur for a number of reasons. One reason could be a lack of joint stability if the disk does not cover the medial pole of the condyle. The occlusion can change due to changes in soft tissue anatomy (disk) or hard tissue anatomy (condyle/ joint socket). • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have you had multiple occlusal appliances? • An occlusal appliance is the most common initial treatment for patients with structurally altered joints. If multiple occlusal appliances trying to change the occlusion at the tooth level cannot resolve the problem, the issue may be at the joint level. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have you had multiple bite adjustments? • Similar to occlusal appliances, if multiple attempts to balance the occlusion at the tooth level through equilibration are not successful, the changing bite may be due to structural changes at the joint level. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have you had upper or lower jaw surgery to change your bite? • If a patient requires orthognathic surgery, there is an increased likelihood of altered growth of the mandible,

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maxilla, or both. Joint imaging with MRI and CBCT should be a routine part of the presurgical workup for all orthognathic cases. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • The third history is the history of previous treatment. • Question: Have you ever been in a car accident? • Question: How many car accidents have you been in? • Question: How fast were you going at the time of each accident? • Question: How old were you for each accident? • Multiple car accidents, car accidents faster than 20 mph, and car accidents before 18 years of age all increase the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. Question: Have you ever had a concussion? Question: How many concussions have you had? Question: How did each concussion happen? Multiple concussions and concussions before 18 years of age increase the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • • • •

• Question: Have you ever had sutures in the head or neck area? • Question: Why did you need sutures? • Question: Have you ever had sutures in your chin? • Chin impact and facial trauma increase the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have you ever had medical surgery requiring a breathing tube? • Question: How many times have you had surgery with a breathing tube? • Multiple intubations and intubations early in life increase the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have your tonsils and/or adenoids been removed? • Question: Have you had your third molars removed? • Removing tonsils and third molars increase the risk for structural changes to the TM joints.

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• IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did you participate in contact sports in your growing years? • Question: Do you remember any head contact while participating in contact sports? • Participation in contact sports during the growing years increases the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did you have any falls onto your face before your 12th birthday? • Question: Early injuries in life increase the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Have you had multiple injuries? • Multiple injuries increase the risk for structural changes to the TM joints. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • The fourth history a pain history. • Question: Do you have pain higher than a 5 on a 1–10 scale? • Muscle pain tends to be more achy in nature and will tend to have lower pain levels as opposed to structural changes in the joint. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Do you have sharp or stabbing pain? • Sharp or stabbing pain will correlate to changes at the bone level in many patients. Patient with eroded bone, small bone, or edematous bone may present with sharp or stabbing pain. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Did you have pain earlier than age 18? • Growing patients should not experience pain. If pain occurs in the growing patient, it may be prudent to assess the joint anatomy with MRI/CBCT imaging. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT. • Question: Do you have headaches on a regular basis?

Assessing the Temporomandibular Joint Condition in Surgically Facilitated Orthodontic Treatment planning

• Many patients who present with headaches have undiagnosed joint issues. If a patient has headaches and the headaches have not been treated successfully, it would be prudent to assess the condition of the jaw joints with MRI/CBCT imaging. • IF YES, INCREASED CHANCE FOR A PIPER 4A/4B/5A/5B JOINT.

Occlusal and Facial Exam of the Patient The second component of the exam is the occlusal and facial evaluation. Assessing the occlusion at the tooth level can give insights into the TM joint condition. Assuming normal growth and development, the TM joint disk will be in the proper position in a Class I occlusion and should result in normal anterior guidance. In this situation, the anterior teeth will be coupled or close to being coupled. If the teeth are uncoupled greater than the thickness of the disk (2 mm), it is important to understand the anterior tooth uncoupling can be the result of a lack of development in the growing patient or a lack of maintenance of occlusal stability on the growing patient.

Fig. 15 MIP

Fig. 17  RL coronal CBCT

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There are several key points to understand about assessing the occlusion at the tooth level and how it can give insights into the condition of the TM joints. The first key point is that to assess the occlusion and relate the occlusion to the TM joint condition accurately, it is necessary to evaluate the occlusion when the joints are fully seated in the joint socket. A common clinical scenario is the patient who appears to have anterior tooth coupling in maximum intercuspation (Fig. 15). However, when the occlusion is evaluated in a fully seated condylar position, the anterior teeth can uncouple resulting in a significantly different occlusion (Fig. 16). The structural changes in the TM joints are evident in the coronal view of the right and left TM joints shown in Fig.  17. If the occlusion is not evaluated in a fully seated condylar position,the patient can compensate and change the tooth position by altering the mandibular position [8]. The second key point to understand is whether the teeth are in their normal position or if the tooth position has been altered due to orthodontic treatment. It is important to understand that assessing the occlusion at the tooth level to gain insight into TM joint condition may be inaccurate if the tooth has been moved from their normal position. A common clinical scenario is the patient who has a large overjet and had maxillary first premolars extracted during orthodontic treatment to retract the

Fig. 16  Fully seated condylar position (FSCP)

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maxillary anterior teeth. The anterior teeth may couple in a fully seated condylar position (Fig. 18) but the joint defect is still present despite the “normal” anterior occlusion (Fig. 19). The third key point to understand is the anterior tooth relationship should be evaluated assuming that the teeth have a normal axial inclination in the maxilla and mandible. It is important to understand that assessing the occlusion at the tooth level to gain insight into TM joint condition may be inaccurate if the teeth are not evaluated assuming a normal tooth

Fig. 18  GR Max pre ext

Fig. 19 GR_CBCT Fig. 20  BH Max retro

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axial inclination. A common clinical scenario is the patient who has retroclined upper anterior teeth either before or after orthodontic treatment (Fig.  20). If the teeth are assumed to have normal tooth inclination, the anterior teeth can uncouple significantly. The occlusion is evaluated by assessing the distance between of the lower and upper anterior teeth with the joints in the socket assuming a normal tooth inclination and the prior tooth position before orthodontic treatment. This distance is assessed in a horizontal and vertical dimension. If the distance is greater than the thickness of the disk, the likelihood increases that the disk is not maintaining the vertical dimension of the TM joint. The structural changes in the joints are shown in the coronal views on the CBCT (Fig. 21). In addition to assessing the occlusion, the facial profile must also be evaluated. Facial asymmetries are common in patients who have structurally altered joints (Fig.  22). In many cases, this is the result with a disk displacement resulting in a lack of development of the full genetic potential in the growing patient. The joint on the side of the asymmetry is typically the suspected joint. Retrognathia is also a common finding in patients with structurally altered joints. Patients who present with facial asymmetries or retrognathia should be evaluated for structural changes in the TM joint [13, 23].

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Fig. 21  BH CBCT

Fig. 22 SW

Load Testing of the TM Joint Complex The third component of the exam is load testing. Dawson [24] developed load testing as a method to assess if the TM joint could withstand incremental loads applied without pain. The joints are seated in the socket using light pressure and the patient is asked if there is any tension, tenderness of pain at the joint level. If the response is positive to light loading (1–2 pound of pressure), it is possible to attempt muscle deprogramming with cotton rolls or an anterior tooth contact appliance. If the response is negative to light loading, the load test proceeds to moderate pressure (3–4 pounds of pressure). The joints are seated in the socket using moderate pressure and the patient is asked if there is any tension, tenderness of pain at the joint level. If the response is positive to moderate loading (3–4 pounds of pressure), it is possible to attempt muscle deprogramming with cotton rolls or an anterior tooth contact appliance. If the response is negative to

moderate loading, the load test proceeds to firm pressure (5–6 pounds of pressure). If the response is positive to firm loading (5–6 pounds of pressure), it is possible to attempt muscle deprogramming with cotton rolls or an anterior tooth contact appliance. If the response is negative to firm loading, the TM joint is determined to be stable. While load testing can give a great deal of information about the TM joints, it is important to understand the details of load testing. The first limitation is that load testing will provide a high percentage of false negative tests since many TM joints are unstable yet nonpainful. The second limitation is that false negative load tests increase in growing patients since many growing patients do not experience pain in structurally altered joints. The last think to understand about load testing is that there is a low false negative test rate in patients who test positive to light loading. If joints are painful with light loading, there is a high likelihood there are structural changes in the jaw joints.

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TM Joint Auscultation The fourth component of the exam is listening to the joints. It is possible to use a stethoscope, doppler auscultation, or joint vibration analysis to listen to the joints. The purpose of listening to the jaw joint is to hear the noise generated by the friction generated as the condyle functions against the disk, the retrodiscal tissue or the joint socket. If there is not any noise generated during movements, the assumption is the disk covering the condyle completely. If there is noise generated during movements, the assumption is the disk not covering the condyle completely [8]. The noise is assessed to try to determine the structural change in the jaw joint. Joint noise can be heard in rotational or translational movements of the mandibular. The medial pole of the condyle is compressed during rotational movements, and the lateral pole of the condyle is compressed during translational movements. If there is audible noise during rotational movements, it would indicate the disk may not be covering the medial pole of the condyle and there is audible noise during translational movements, it would indicate that the disk may not be covering the lateral pole of the condyle. A key factor to understand regarding listening to the jaw joints is that joint noise cannot definitely diagnose joint condition or assess the risk factors in structurally altered TM joints. Listening to the joint using doppler auscultation is an excellent education tool to help patients understand the potential changes in the joint socket.

Range of Mandibular Motion The fifth component of the exam is assessing the range of motion. Normal opening typically ranges from 40-50  mm while normal excursive movement range between 8 and 10 mm. If opening drops to below 30 mm or excursive movements drop to below 6 mm, there is an increased likelihood there of structurally altered joints at both the lateral and the medial pole.

Muscle Palpation The sixth and last component of the exam is muscle palpation. Muscles can be come tender to palpation for several different reasons. If the masticatory muscles are tender to palpation and it correlates to other findings in the exam, it may be prudent to assess the condition of the TM joints. After the exam is completed (history, occlusal/facial evaluation, load testing, doppler auscultation, range of motion, and muscle palpation), the goal is to determine a tentative

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diagnosis of the joint condition. Is it more likely the patient is a Piper Stage 1/2/3A/3B or Piper Stage 4A/4B/5A/5B? If the tentative diagnosis is Piper Stage 1/2/3A/3B, the risk factors are relatively low from a joint perspective. In this situation, treatment planning for surgically facilitated orthodontic therapy can proceed as normal with the assumption the finalized occlusion achieved through SFOT will be stable at the joint level [8]. If the tentative diagnosis is Piper Stage 4A/4B/5A/5B, the risk factors increase from a joint perspective. In these cases, it is helpful at directly visualize the soft tissue and hard tissue components in the TM joint. Magnetic Resonance Imaging (MRI) analysis offers an assessment of disk condition, disk position, and condyle condition through assessing the marrow space in the internal aspect of the condyle. The CBCT offers an assessment of the condyle size, the integrity of the condylar cortical plate, the ramus length, nasal airway anatomy, pharyngeal airway anatomy, and the upper cervical spine. The goal of TM joint imaging is to assess potential joint stability from both an occlusal perspective and a pain perspective. The Piper MRI and CBCT protocol is outlined in Chapter (Dr Shah’s chapter) in this publication [8].

Treatment Planning When developing a treatment plan from a joint perspective, it is helpful to think of treatment planning in three phases. Phase I includes treatment options that are designed to change the loading on the injured TM joints and hoping adaptation at the joint level. This may include occlusal appliances [25], physical or chiropractic treatment [26], medications [27], and injection therapy. Phase II includes treatment options that directly influence the anatomy in the TM joints with the hope the change in joint tissue will lead to adaptation at the joint level. Examples of this type of treatment include arthrocentesis [27], arthroscopy [28], disk repair [29–33], disk replacement [34–37], condylar reinforcement with rib grafting [38] or condylar and disk replacement with artificial joints [39]. TM joint surgical options [40] are discussed in Chapter(Dr Shah’s chapter). Phase III treatment includes treatment options that are designed to change tooth position or contour with the goal of changing tooth position/ condition and hoping for adaptation at the tooth level. When treatment plans will include Phase III treatment, it is vital to recognize which patients may have potentially unstable occlusion or pain due to structurally altered TM joints. Identifying patients who require malocclusion management via orthodontics with or without SFOT is critical to ensure a stable occlusion. Common imaging findings that can result in unstable orthodontic outcome with the occlusion include large, herniated disks in the 11:00 position (Fig. 23), small condylar bone (Fig. 24) [40], eroded condy-

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11:00

Large 11:00 disk

Fig. 25  Eroded bone Fig. 23 Disk

Fig. 26  Edematous bone Fig. 24  Small bone

lar bone (Fig. 25) [40], or edematous bone (Fig. 26) [41, 42]. If these conditions are present, it is recommended to begin with Phase I treatment and verify occlusal stability and comfort before beginning Phase III treatment. Acknowledgments  I would like to acknowledge Dr. Mark Piper for developing the content in this chapter and for bringing predictability to the treatment planning process through understanding the condition of the TM joints.

References 1. Zúñiga-Herrera ID, Herrera-Atoche JR, Escoffié-Ramírez M, Casanova-Rosado JF, Alonzo-Echeverría ML, Aguilar-Pérez FJ. Malocclusion complexity as an associated factor for temporomandibular disorders. A case-control study. Cranio J Craniomandib Pract [Internet]. 2021;00(00):1–6. https://doi.org/10.1080/0886963 4.2020.1868907. 2. Schellhas KP, Keck RJ. Disorders of skeletal occlusion and temporomandibular joint disease. Northwest Dent. 1989;Jan-Feb:35–42.

126 3. Alomar X, Medrano J, Cabratosa J, Clavero JA, Lorente M, Serra I, et al. Anatomy of the temporomandibular Joint. Semin Ultrasound CT MRI. 2007;28(3):170–83. 4. Choukas N, Sicher H.  The structure of the temporomandibular joint. Oral Surg Oral Med Oral Pathol. 1960;13(10):1205–13. 5. Drace JE, Enzmann DR. Defining the normal TM joint: closed, partially open and open-mouth MR imaging of asymptomatic subjects. Radiology. 1990;177:67–71. 6. Rammelsberg P. Variability of disk position in asymptomatic volunteers and patients with internal derangements of the TMJ. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1997;83:393–9. 7. Provenzano M, Chilvarquer I, Fenyo-Pereira M.  How should the articular disk position be analyzed? J Oral Maxillofac Surg. 2012;70:1534–9. 8. Piper Mark. Temporomandibular joint imaging. In Handbook of research on clinical applications of computerized occlusal analysis in dental medicine. Pennsylvania: IGI Global, 2020; p.  582–697. doi:https://doi.org/10.4018/978-­1-­5225-­9254-­9.ch009.Web. 24 Oct. 2019 9. Schiffman E, et al. Diagnostic criteria for temporomandibular disorders (DC/TMD) for clinical and research applications: recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group. J Oral Facial Pain Headache. 2014;28(1):6–27. https://doi.org/10.11607/jop.1151. 10. Wilkes CH.  Internal derangements of the temporomandibular joint: pathological variations. Arch Otolaryngol Neck Surg. 1989;115:469–77. 11. Schellhas KP. Unstable occlusion and temporomandibular joint disease. J Clin Orthod. 1989;23(5):332–7. 12. Schellhas KP.  Internal derangement of the temporomandibular joint: radiologic staging with clinical, surgical, and pathologic correlation. Magn Reson Imaging. 1989;7:495–515. 13. Schellhas KP, Piper MA, Omlie MR.  Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients. Am J Roentgenol. 1990;11(3):541–51. 14. Bryndahl F, Warfvinge G, Eriksson L, Isberg A. Cartilage changes link retrognathic mandibular growth to TMJ disc displacement in a rabbit model. Int J Oral Maxillofac Surg. 2011;40:621–7. 15. Schellhas KP, Piper MA, Bessette RW, Wilkes CH.  Mandibular retrusion, temporomandibular joint derangement, and orthognathic surgery planning. Plast Reconstr Surg. 1992 Aug;90(2):218–29. 16. Schellhas KP, Pollei SR, Wilkes CH.  Pediatric internal derangements of the temporomandibular joint: effect on facial development. Am J Orthod Dentofac Orthop. 1993;104(1):51–9. 17. Nebbe B, Major P, Prasad, Prasad N, Kamelchuck L.  TMJ internal derangement and adolescent craniofacial morphology. Angle Orthod. 1997;67(6):407–14. 18. Burke G, Major P, Glover K, Prasad N. Correlations between condylar characteristics and facial morphology in Class II preadolescent patients. Am J Orthod Dentofac Orthop. 1998;114(3):328–36. 19. Byun ES, Ahn SJ, Kim TW. Relationship between internal derangement of the temporomandibular joint and dentofacial morphology in women with anterior open bite. Am J Orthod Dentofac Orthop. 2005;128(1):87–95. 20. Flores-Mir C, Nebbe B, Heo G, Major PW. Longitudinal study of temporomandibular joint disc status and craniofacial growth. Am J Orthod Dentofac Orthop. 2006;130(3):324–30. 21. Sylvester D.  Association between disk position and degenerative bone changes of the temporomandibular joints: an imaging study in subjects with TMD. J Craniomandib Pract. 2011;29(2):117–26. 22. Manfredini D, et  al. TM joint disorders in patients with different facial morphology. A systematic review of the literature. J Oral Maxillofac Surg. 2016;74(1):29–46. 23. Legrell PE, Reibel J, Nylander K, Horstedt P, Isberg A.  Temporomandibular joint condyle changes after surgically induced non-reducing disk displacement in rabbits: a macroscopic and microscopic study. Acta Odontol Scand. 1999;57:290–300. 24. Dawson PE.  Functional Occlusion: From TMJ to Smile Design. Maryland Heights: Mosby; 2007.

J. McKee 25. Kreiner M. Occlusal stabilization appliances: evidence of their efficacy. JADA. 2001;132(6):770–7. 26. Ouanounou A, Goldberg M, Hass D. Pharmacotherapy in temporomandibular disorders. Rev J Can Dent Assoc. 2017;83:7. 27. Furto ES, Cleland JA, Whitman JM, Olson KA.  Manual physical therapy interventions and exercise for patients with temporomandibular disorders. Cranio. 2006;24(4):283–91. https://doi. org/10.1179/crn.2006.044. 28. Şentürk MF, Yazıcı T, Gülşen U. Techniques and modifications for TMJ arthrocentesis: a literature review. Cranio. 2018;36(5):332– 40. https://doi.org/10.1080/08869634.2017.1340226. 29. Holmlund A, Hellsing G, Wredmark T.  Arthroscopy of the temporomandibular joint: a clinical study. Int J Oral Maxillofac Surg. 1986;15(6):715–21. 30. Piper MA.  Microscopic disk preservation surgery of the temporomandibular joint. Oral Maxillofac Surg Clin N Am. 1989;1(2):279–301. 31. Zhou Q, Zhu H, He D, Yang C.  Modified temporomandibular joint disc repositioning with miniscrew anchor: part II  — stability evaluation by magnetic resonance imaging. J Oral Maxillofac Surg [Internet]. 2016:1–7. https://doi.org/10.1016/j. joms.2018.07.016. 32. Zhu H, He D, Yang Z, Song X, Ellis E. The effect of disc repositioning and post-operative functional splint for the treatment of anterior disc displacement in juvenile patients with Class II malocclusion. J Cranio-Maxillofacial Surg. 2018; https://doi.org/10.1016/j. jcms.2018.09.035. 33. Liu Z, Xie Q, Yang C, Chen M, Bai G, Abdelrehem A. The effect of arthroscopic disc repositioning on facial growth in juvenile patients with unilateral anterior disc displacement. J Cranio-Maxillofacial Surg [Internet]. 2020;48(8):765–71. https://doi.org/10.1016/j. jcms.2020.05.016. 34. Shen P, Sun Q, Xu W, Zheng JS, Zhang S, Yang C.  The fate of autogenous free fat grafts in the human temporomandibular joint using magnetic resonance imaging. J Craniomaxillofac Surg. 2015;43:1804–8. 35. Younis M, Shah AA, Hassan S, Kapoor M, Rashid A. Abdominal Dermis-fat graft versus conventional temporalis myofascial flap interposition in temporomandibular joint ankylosis: a prospective clinical comparative study. J Maxillofac Oral Surg [Internet]. 2020; https://doi.org/10.1007/s12663-­020-­01455-­3. 36. Younis M, Shah A, Ahmed I.  Viability and volumetric analysis of free autogenous dermis fat graft as interpositional material in TMJ ankylosis. J Maxillofac Oral Surg [Internet]. 2020; https://doi. org/10.1007/s12663-­020-­01413-­z. 37. Rahman SA, Rahman T, Hashmi GS, Ahmed SS, Ansari MK, Sami A.  A clinical and radiological investigation of the use of dermal fat graft as an interpositional material in temporomandibular joint ankylosis surgery. Craniomaxillofac Trauma Reconstr. 2020;13(1):53–8. 38. Shenaq SM, Klebuc JA.  TMJ reconstruction during vascularized bone graft transfer to the mandible. Microsurgery. 1994;15:299–304. 39. Wolford LM, Cassano DS.  Autologous fat grafts placed around temporomandibular joint (TMJ) total joint prostheses to prevent heterotopic bone. Autologous Fat Transfer [Internet]. 2006:361–82. Available from: http://www.springerlink.com/ index/10.1007/978-­3-­642-­00473-­5 40. Dimitroulis G.  Temporomandibular joint surgery: What does it mean to the temporomandibular disorder practitioner? Egypt J Oral Maxillofac Surg. 2011;2:2–7. 41. Dias IM, Coelho PR, Assis NMSP, Leite FPP, Devito KL. Evaluation of the correlation between disc displacements and degenerative bone changes of the temporomandibular joint by means of magnetic resonance images. Int J Oral Maxillofac Surg. 2012;41:1051–7. 42. Larheim TA, Sano T, Yotsui Y.  Clinical Significance of Changes in the Bone Marrow and Intra-Articular Soft Tissues of the Temporomandibular Joint. Semin Orthod [Internet]. 2012;18(1): 30–43. https://doi.org/10.1053/j.sodo.2011.10.006.

Part III The Orthodontic Perspective

The Transverse Dimension: CBCT Treatment Planning in Growing Children Claire Ferrari

Why Are We Narrow? The Importance of the Transverse Dimension The growth of the human face is greatly determined by genetic influences. Children inherit facial features from their parents, and disruptions in genetic code are linked to a variety of craniofacial anomalies [1]. However, the growth of the face is also greatly influenced by epigenetic influences. Dr. Melvin Moss coined the term “functional matrix” when describing the way the function of the muscles and tissues of the face influence the growth of the facial bones [2–4]. The way we breathe, and the position/function of the tongue through chewing, swallowing, and speech influences the growth of the face. Habitual rest position and pressure gradients are also included in this area of “function.” Primate babies are obligate nasal breathers and only breathe through the mouth when forced to. Environmental influences that lead to increased nasal resistance and mouth breathing have a negative impact on the development of the maxilla [5, 6]. A 1981 USCF study by Harvold, Vargervik and colleagues showed that low tongue posture through forced mouth breathing in growing primates led to significant changes in facial growth including narrowing of the maxilla [7]. The group showed changes in muscle recruitment patterns resulting in changed posture and function in these experimental animals [8, 9]. With a narrower maxilla, there is increased resistance to nasal airflow because the bones that make up the two halves of the maxilla, joining at the maxillary suture, are the same bones that make up the floor of the nose. The increased resistance to nasal airflow leads to functional and postural changes that result in a narrow maxilla [10, 11]. Thus, a negative feedback loop occurs, Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/978-­3-­030-­90099-­1_10. C. Ferrari (*) Private Practice, Ferrari Orthodontics, Berkeley, CA, USA e-mail: [email protected]

leading to more mouth breathing. Even in individuals with “normal facial growth patterns” using AP and vertical cephalometric norms, oral breathing children have differences in airway dimensions when compared to nasal breathing children [12]. The nose warms, humidifies, and filters the air that we breathe to condition it for the lungs. Nasal breathing also stimulates the release of nitric oxide, a signaling molecule that has antimicrobial properties and improves oxygen exchange in the lungs [13–15]. Breathing through the mouth does not stimulate this same release of nitric oxide and leads to swelling of the turbinates, making breathing through the nose more difficult, contributing further to the negative feedback loop. This change toward mouth breathing and narrowing of the palate in children may be due to an increase in allergies due to toxins in the environment [16], potentially as a result of a hyperactive immune response, as well as an increase in ragweed production due to more carbon dioxide in the atmosphere [17, 18]. There is also  a feedback loop between mouth breathing, tongue position, and tonsil size [19, 20]. Enlarged tonsils impact the position of the tongue, promoting tongue thrust and mouth breathing, and mouth breathing leads to enlarged tonsils. A softer diet, and reduced masticatory forces, may also be an epigenetic influence contributing to this negative feedback loop of a diminished transverse dimension and increase in crowding and malocclusion [21–23]. Cultures that have not been exposed to industrialization have greater tooth wear and far less incidence of dental crowding and malocclusion [24, 25]. Anthropologist R.S. Corruccini’s research on skeletal remains demonstrates that the human craniofacial complex has been narrowing. It is important to understand that our “norms” are based on postindustrial skulls and may warrant a re-evaluation taking into account the way our skulls are changing to our detriment. Orthodontists are specialists in understanding the growth of the craniofacial complex and are well positioned to evaluate airways in young children and adolescents during routine examinations [26, 27]. Screening early for sleep disturbed

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_10

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breathing should be standard practice for orthodontists and dentists who see children. The narrowing of the maxilla referred to above leads to more crowding and higher incidence of sleep disturbed breathing [11]. Christian Guillmenault, the father of sleep medicine, has concluded that “In children of normal weight, obstructive sleep apnea is a disorder of oral-facial growth” [28], and there is a growing body of evidence supporting this relationship [29]. Sleep disturbed breathing in children, which may include just snoring, has profound implications on physical, mental, and cognitive health [30–33]. A large percentage of children diagnosed with ADHD have sleep disordered breathing [34] and may be medicated unnecessarily. Identifying and being a partner in treating pediatric sleep disturbed breathing is a service we can provide our patients to help them thrive. Crowded dentition is caused by a decrease in the size of the bony bases, not due to large tooth size [35]. Canines are the most commonly impacted teeth [36]. They develop higher in the maxilla and usually have the last pick of space for eruption. Early expansion of the maxilla is a way to “res-

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cue” the eruption path of permanent canines [37, 38] and is a way to make more room for teeth to erupt properly into better periodontal support [35, 39]. Early expansion is also a way to treat children with sleep disturbed breathing [40–44]. The timing of orthodontic expansion depends on the presenting symptoms and the degree of crowding. It is essential for every orthodontic patient to fill out a sleep questionnaire as part of their intake. Pediatric Sleep Questionnaire (PSQ) is a validated screening tool to identify children with sleep disordered breathing [45] (Fig.  1). Orthodontists who focus on sleep and breathing have begun to treat patients in the 3–5 year old range if they present with snoring and/or mouth breathing with minimal space between the primary teeth. Many patients with evidence of sleep disturbed breathing in the primary dentition already show precursors to poor craniofacial growth, and left untreated, these usually persist and often become more severe later [46]. Snoring is not normal in children and has been associated with impacts on cognitive development [33]. Treating these children early can help mitigate cognitive and behavioral impairments.

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The Transverse Dimension: CBCT Treatment Planning in Growing Children

PEDIATRIC SLEEP QUESTIONNAIRE PATIENTS UNDER 18 YEARS OF AGE Last Name

First Name

Age

Date

Please answer on behalf of your child for the past month. If you don’t know, circle “?” While sleeping, does your child ... 1.

snore more than half the time?

Yes / No / ?

2.

always snore?

Yes / No / ?

3.

snore loudly?

Yes / No / ?

4.

have trouble breathing, or struggle to breathe?

Yes / No / ?

5.

have “heavy” or loud breathing?

Yes / No / ?

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have you ever seen your child stop breathing during the night?

Yes / No / ?

Does your child ... 7.

tend to breathe through the mouth during the day?

Yes / No / ?

8.

have a dry mouth on waking up in the morning?

Yes / No / ?

9.

occasionally wet the bed?

Yes / No / ?

10. wake up feeling unrefreshed in the morning?

Yes / No / ?

11. have a problem with sleepiness during the day?

Yes / No / ?

12. has a teacher commented that your child appears sleepy during the day?

Yes / No / ?

13. is it hard to wake your child up in the morning?

Yes / No / ?

14. does your child wake up with headaches in the morning?

Yes / No / ?

15. did your child stop growing at a normal rate at any time since birth?

Yes / No / ?

16. is your child overweight?

Yes / No / ?

My child often... 17. does not seem to listen when spoken to directly

Yes / No / ?

18. has difficulty organizing task and activities.

Yes / No / ?

19. is easily distracted by extraneous stimuli.

Yes / No / ?

20. fidgets with hands or feet or squirms in seat.

Yes / No / ?

21. is ‘on the go’ or often acts as if ‘driven by a motor’.

Yes / No / ?

22. interrupts or intrudes on others (e.g. butts into conversations or games)

Yes / No / ?

Fig. 1  Example of a pediatric sleep questionnaire for patients under 18 years of age

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 hy Use CBCT to Evaluate the Transverse W Dimension Orthodontic diagnosis and treatment planning take into account all three planes of space, but the transverse dimension is often ignored or is an afterthought because most orthodontists have been trained with, and many still use, 2D imaging. A panoramic radiograph and lateral cephalometric radiograph have been the norm for orthodontic diagnosis and treatment planning since the introduction of cephalometry. PA cephs have been used, but much more rarely, and for skeletal asymmetries rather than for transverse discrepancies. We are in a “phase transition” where more and more offices are making the change to CBCT imaging, and the hope is that it will be the norm for records on every patient, every time. The argument against the use of CBCT for every patient due to radiation exposure no longer holds weight when using machines designed to take diagnostic quality images at low exposure levels. Dr. John Ludlow of UNC has rigorously studied X-ray dosimetry for decades and found that it is possible to do 3D imaging at comparable and even lower doses than standard 2D ceph/pan protocols [47]. We can now have more information with less radiation [48]. It is not possible to quantify skeletal discrepancies in the transverse dimension clinically or with stone models. In an important 2012 CBCT study, Miner et al. found that patients without crossbites can have significant skeletal transverse discrepancies that warrant treatment [49] (Fig.  2). Skeletal discrepancies in the transverse dimension often occur without clinical presence of posterior crossbites due to dental compensations. Miner’s group found that the non-crossbite patients with “superior convergent” dental inclinations had skeletal discrepancies greater than the unilateral crossbite patients and a skeletal discrepancy that was close to that of the bilateral crossbite group. CBCT imaging is an invaluable tool for modern orthodontic treatment because it allows for

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far more accurate diagnosis and treatment planning than 2D imaging, especially in the transverse dimension, and non-­ diagnosis/misdiagnosis of the transverse dimension has significant impacts for patients. CBCT allows us to see the patient as they are in all three planes of space without distortion. This imaging enables the orthodontist to determine the quality of periodontal support and alveolar housing significantly better than ceph and pan [50, 51]. In addition, CBCT imaging enables evaluation of the nasal structure, sinuses, tongue position, and airway size, including size of tonsils and adenoids [52]. This facilitates referrals as needed to support the care of the patient, such as to an ENT, allergist immunologist, or myofunctional therapist. Transverse growth of the maxilla is completed earlier than other maxillofacial structures [53, 54] and is completed earlier in facial development than AP or vertical growth [55]. Underdevelopment of the maxilla in the transverse dimension is probably the most common skeletal problem in the craniofacial complex [56], and it may be the most malleable when treated early [57]. While there is evidence that expansion of the maxilla was practiced far earlier, transverse expansion of the two halves of the maxilla at the midpalatal suture was first described in the literature by E.C. Angell in 1860 [58] and the concept was reintroduced by Haas in the 1960s [59, 60]. The timing of diagnosis of transverse skeletal discrepancies has an important impact on the treatment modalities used to correct the discrepancy. The more mature the child, the less skeletal expansion and the more dental tipping with tooth-borne expanders due to the maturation of the midpalatal suture. However, there is tremendous variability in the developmental stages of the midpalatal suture relative to chronological age [61]. Even in young children, Krebs (1964) showed that with tooth-borne orthopedic expansion, 50% is skeletal while 50% is dental expansion. He found that adolescent children had 35% skeletal expansion and 65% dental expansion [62]. James McNamara and colleagues at

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Fig. 2  From the AJO-DO Miner et al. 2012 article. (a) Control group. (b) Superior convergent group. (c) Inferior convergent group

The Transverse Dimension: CBCT Treatment Planning in Growing Children

the University of Michigan published a paper cataloguing their four decades of research on orthopedic expansion [63]. They conclude that expanding in the early mixed dentition is much more effective at producing skeletal change, especially when the lower arch is expanded as well. They note, when rapid maxillary expansion (RME) treatment is performed after the pubertal growth spurt, maxillary adaptations to expansion therapy shift from the skeletal level to the dentoalveolar level. However, even with pre-pubertal expansion, there is a significant component of splaying of the alveolar segment and maxillary dental tipping [64, 65]. Orthodontic tooth movement must take into account the supporting periodontal housing. Vanarsdale has reported that the transverse dimension may be the most crucial risk marker for facial gingival recession [66]. He has been a pioneer in advocating the proper treatment of the transverse dimension to avoid adverse periodontal outcomes and to improve occlusal and esthetic outcomes [67–69], as well as to improve the airway [70]. When the transverse dimension is not properly addressed, dental compensations lead to periodontal recession both on the facial of the maxillary teeth tipping buccally and on severely lingually inclined lower posterior teeth. The goal of maxillary expansion is to create a skeletal effect and avoid dentoalveolar side effects such as dental tipping because dental tipping relapses even in growing patients [71, 72]. However, these side effects are common when using tooth supported expanders and can lead to a decrease in alveolar bone height, fenestration, and bone dehiscence when used in growing patients in the permanent dentition [66, 73, 74]. In an effort to reduce these negative side effects, bone-borne expanders (also called MARPE: Microimplant-­ Assisted Rapid Palatal Expander) have been developed and are becoming more widely used [75–82]. Celenk-Koca and colleagues in a 2018 prospective randomized clinical trial found that bone-borne expanders increased the extent of skeletal changes up to 2.8 times that of tooth-borne expansion and did not result in any dental side effects [83]. In addition to reducing dental side effects, there is a growing body of evidence that bone-borne expanders improve nasal breathing and can be effective in treating OSA [84]. Bazargani and colleagues, in a 2017 randomized control trial, compared tooth-borne and bone-borne expanders. They found that the bone-borne expanders induced significantly higher nasal air flow and lower nasal air resistance than the tooth-borne appliance [85]. The bone-borne appliances expand in a more parallel fashion than tooth-borne expanders, including in the upper anterior and posterior part of the maxilla which is more difficult to expand [86]. In a recent paper, Peredes et al. describe an assessment using novel angular measurements to quantify the differential components of expansion (skeletal expansion, bone bending, and dental tipping) since expansion with a bone-borne expander is archial in nature. The whole zygomaticomaxillary complex widens in an arc, the

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fulcrum being the zygomaticotemporal suture. Utilizing this method for measuring, they found over 95% skeletal expansion with little to no bone bending or dental tipping [87]. A commonly use bone-borne expander is the Maxillary Skeletal Expander (MSE) [88].

 rthodontic Diagnosis and Treatment O Planning of the Transverse Dimension Using CBCT Surface Map Modeling In our office we diagnose and treatment plan using a surface mapped segmented model of the patients’ jawbones and teeth. For their initial records, a CBCT (iCAT [89]) is taken on every patient and sent to Osteoid [90] to create an “Anatomodel,” a surface mapped segmented model of the jaws and dentition. Before looking at the model, we evaluate the sections: sagittal, axial, and coronal, with special attention to nasal anatomy, sinus condition, and tongue position. Using the sagittal section view, the software can create a rendering of the minimum cross-sectional area and total volume of the airway. There are limitations to the reliability of this measurement, because it is a static snapshot in time of dynamic space, but it is useful for getting an idea of airway restriction or small airway space, often caused by large tonsils and/or adenoids, but also due to reduced tongue space as a consequence of suboptimal growth (transverse, AP, and/or vertical). When the adenoids are enlarged enough to touch the posterior of the turbinates, it is very difficult for the patient to breathe through their nose. Referral to an ENT as well as a myofunctional therapist is warranted to help reestablish nasal breathing which is essential for proper oral rest position [91]. It is also important to clinically check the lingual frenum for all patients to see if there is a restriction, limiting the mobility of the tongue. It is important to respect the capacity of the tongue to work with you, or against you. In this regard, myofunctional therapy is an important allied health discipline that can help establish behavior patterns that will encourage nasal breathing. Normal tongue rest posture, tone, and function, as well as proper function of the other orofacial muscles are essential for treatment effectiveness and stability [92]. Correlations with answers from the health history form and clinical exam may lead to referrals to an ENT, allergist/immunologist, sleep physician, or myofunctional therapist. Moving to the model, we begin by looking at the mandible. Here, the degree of compensation (lingual tipping) of the lower molars can be visualized (Fig. 3b). When the full opacity of the jawbone is brought in, the molars can be uprighted to reduce excess curve of Wilson and brought laterally to be centered on the jawbone (Fig. 3c). The amount of bone available can be clearly visualized on the anatomodel. Once the lower molars are brought in the center of the jawbone, a measurement in millimeters can be taken from

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Fig. 3  Phase I Expansion. (a) Initial model. (b) Occlusal view of lower arch showing lower first molars lingual inclination. (c) Mock-up of lower arch decompensation. The widget is centered on the tooth. After the lower first molars are uprighted, a measurement is taken from central groove to central groove of each first molar to determine the width needed for the upper arch. (d) Frontal view of model after lower arch is decompensated and prior to upper expansion. Note that once the lower arch is uprighted, the upper first molars are in crossbite. (e) Occlusal view of upper arch prior to expansion. The more superior measurement corresponds to the measurement from the uprighted lower arch. The more inferior number is the current measurement of the upper arch measured from mesiopalatal cusp of each first molar. The discrepancy for

this case was about 8  mm. (f) Occlusal view showing the upper arch expanded to coordinate with the width needed. The expansion is done by placing the widget on each half of the maxilla and expanding half of the amount of expansion for each side. The space that forms between the upper central incisors is consolidated by moving U2–2 together, simulating partial braces and redistribution of the space for the  permanent canines. (g) Final frontal view of mocked up phase I expansion. Note that the expansion mocked up is pure “skeletal” expansion. Depending on the expansion appliance used and the age of the patient, the amount of skeletal expansion and dentoalveolar “tipping” will vary. This needs to be understood by the practitioner in order to know what to expect clinically, and can be part of the conversation with the parents

central fossa to central fossa of the permanent first molars (Fig. 3c). This measurement will determine the amount of expansion needed for the upper arch. The next step is to take the upper arch and measure from the tip of the mesiopalatal cusp from upper first molar to upper first molar (Fig.  3e). By taking the difference of this measurement with the uprighted lower molar fossa measurement and dividing by two, we can determine the amount of expan-

sion needed on each side of the maxilla. By selecting each half of the maxilla and moving laterally to the predetermined amount of expansion needed per side, the occlusion can be made ideal (Fig.  3f). The caveat is that when the upper first molars are buccally tipped, the amount of expansion needed on each side is greater to account for the necessary uprighting of the upper molars to decrease flaring. In these situations, it may be best to upright the molars

The Transverse Dimension: CBCT Treatment Planning in Growing Children

first and then measure the width from palatal cusp tip to palatal cusp tip. Once the expansion is completed, the upper incisors can be moved into the new space formed in the center. Note this mock-up shows “pure skeletal” expansion, the discrepancy between what the mock-up shows and what will happen clinically is discussed below. In the mixed dentition, the closure of the space between the upper anterior teeth simulates the orthodontic movement of consolidating space to make room for the maxillary permanent canines, which usually do not have enough room when the maxilla is narrow (Fig. 3f). On the lower arch in the mixed dentition, we generally use the space gained by uprighting the curve of Wilson to distribute space around the primary canines and resolve any crowding of the lower anterior segment. There is also “E space” available on the lower arch to further address crowding in mixed dentition cases. When the maxilla is the ideal width to coordinate with the mandible, and lower teeth are decompensated, lower arch crowding is rarely an issue in the mixed or adolescent permanent dentition. Note that for the patient in Fig. 3, the degree of crowding caused the upper lateral incisors to be “hooked” on the primary canines, and the upper right central incisor was blocked from erupting normally. When the crowding is so severe that the incisors are not able to erupt normally, the permanent canines are all but certain to be impacted. Early expansion allows for the eruption of the incisors into healthy bone and periodontal support. Figures 4 and 5 show a frontal view of the CBCT volume (Fig. 4) and coronal sections (Fig. 5) of the patient in Fig. 3 before (a) and after (b) phase 1 expansion where the space was created for the erupting permanent dentition without the need for serial extraction or surgical exposure. Figure 6 shows a case with severe crowding in the

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early mixed dentition. There is significant lingual inclination of the lower molars (Fig. 6b). The lower molars are uprighted and moved buccally to create a guide for how much maxillary expansion is needed (Fig. 6c). Again, notice the crossbite created when the lower molars are decompensated (Fig. 6d). This patient would benefit from more than 10 mm of expansion (Fig. 6e). The mock-up of the expansion shows that there is enough space for the developing dentition when the transverse discrepancy is corrected. Figure 7 shows the frontal view of the CBCT volume rendering of the patient in Fig.  6, pre (Fig.  7a) and post (Fig.  7b) phase 1. Note that enough room was created for the eruption of the permanent teeth, but she would benefit from more skeletal expansion. This is because pure skeletal correction is shown in the mock-up. The practitioner needs to account for the device used and the age of the patient in order to translate this into realistic clinical goals and “over expand” or use a bone-­ borne expander as needed to account for dentoalveolar vs skeletal changes. For some cases, this may mean using two expanders during phase 1, or using a bone-borne expander at the beginning of phase 2 to get the rest of the skeletal expansion needed. Many young patients would benefit from the “pure” skeletal expansion created with a bone-borne expander. It is up to the practitioner to educate families of the differences between bone-borne and tooth-borne expansion outcomes and gauge the willingness to have local anesthesia and miniscrew placement for the added benefit of increased improved nasal air flow and reduced dental tipping. This is especially important in cases with ectopically developing canines or a diagnosis of sleep apnea. The patient in Fig. 6 would likely have been treated with serial extraction by many practitioners. The use of the Single Tooth Anesthesia System [93] has allowed for more comfortable delivery of

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Fig. 4  CBCT Rendering of patient in Fig. 3. (a) Frontal view initial. (b) Frontal view following phase I expansion

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Fig. 5  Coronal sections of patient in Fig. 3. (a) Coronal section prior to expansion. Note the turbinate inflammation and buccal crown tip of the upper molars. (b) Coronal section following phase I expansion. Note the reduction in turbinate inflammation and increased width

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Fig. 6  Phase I Severe Crowding example. (a) Initial anatomodel showing severe crowding. (b) Occlusal view of lower arch prior to expansion. Lingual inclination of the lower permanent first molars is evident, due to compensation for a narrow maxilla. (c) Mock-up of the uprighting of the lower permanent first molars centered in the middle of the jawbone and the measurement taken from central groove to central groove. (d) Frontal view of the lower arch decompensated and the upper arch in crossbite. (e) Occlusal view of the maxillary arch showing the lower measurement taken for the necessary width superior to the

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current measurement from mesiopalatal cusp to mesiopalatal cusp of maxillary permanent first molars. The difference between these two measurements indicates the amount of expansion in mm needed of the maxillary arch. (f) Occlusal view of the maxillary arch following expansion to the desired width. The space between the four incisors is consolidated to distribute space for the permanent maxillary canines. (g) Final frontal view of mocked up expansion. Note that this is showing pure skeletal expansion. There is now space for the permanent maxillary canines

The Transverse Dimension: CBCT Treatment Planning in Growing Children

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Fig. 6 (continued)

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Fig. 7  CBCT Rendering of patient in Fig.  6. (a) Initial frontal view prior to phase I expansion. (b) Final frontal view following phase I expansion. Note that there was a certain percentage of dentoalveolar

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tipping due to use of a tooth-borne expander but there is now enough room for the permanent maxillary canines

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anesthesia to the palate which increases the acceptability of placing bone-borne expanders. A commonly used boneborne expander is the Maxillary Skeletal Expander (MSE) [88]. The simplicity of this design also improves the acceptability of bone supported expansion. Figure 8 shows a case with an ectopically erupting developing canine in the upper right quadrant. This patient has relatively large incisors and it was determined through modeling that bone-borne expansion and extraction of the upper right primary canine would be a better option to improve the eruption path of the canine. Figure 9 shows the frontal CBCT volume rendering of the patient in Fig. 8 pre (Fig. 9a) and post (Fig.  9b) phase 1. One can appreciate the bone at the

level of the roots and the reduced flaring of the erupting canines when compared to the patient treated with a tooth supported expander in Fig. 4. A close-up image of the upper right canine can be seen in Fig. 10, before treatment (Fig. 10a and b), after mock-up (Fig. 10c) and after phase 1 treatment (Fig.  10d). The panoramic radiograph derived from the CBCT does not show the degree of ectopic eruption of the canine (Fig. 11). If expansion is warranted, it is now the norm for us to expand adolescent patients with a bone-borne expander. Figure 12 shows a patient with minimal transverse discrepancy who could be treated with dental expansion as mocked up in Fig. 12b. Figures 12c through 12g show the process of

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Fig. 8  Phase I Ectopic canine. (a) Frontal view of initial anatomodel prior to mock-up. Note that the upper right permanent maxillary canine is ectopically developing over the lateral incisor root. Rapid expansion and maximizing skeletal expansion was recommended for this patient. (b) Occlusal view of the lower arch prior to expansion. Note the lingual inclination of the lower permanent first molars. (c) Mock-up of lower arch decompensation, uprighting the molars and centering them in the jawbone. Then, a measurement is taken from central groove of either first molar to determine width needs for the upper arch. (d) With the lower arch decompensated, this frontal view shows that the upper arch

is narrow. (e) Occlusal view of the maxillary arch illustrating the width discrepancy and the amount of expansion needed. (f) Occlusal view following mock-up of expansion of upper arch. Each half of the maxilla is expanded half of the expansion needed and the four incisors are moved together to consolidate space and make room for the permanent maxillary canines. (g) Final mock-up of expansion showing that the upper right permanent maxillary canine now has room to redirect its course. This is aided by extracting the upper right primary canine as well (not shown)

The Transverse Dimension: CBCT Treatment Planning in Growing Children

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Fig. 9  CBCT rendering of patient in Fig. 8. (a) Initial frontal view showing impacting UR3. (b) Final frontal view showing that after skeletal expansion with an MSE bone-borne expander, the UR3 was able to re-direct course (rescued)

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Fig. 10  Close-up of UR3 of patient in Fig.  8. (a) Initial modeling showing UR3 ectopic eruption path more than 50% over the root of UR2. (b) Initial CBCT rendering showing UR3 ectopic eruption path.

(c) Mock-up modeling of space created for UR3 in attempt allowed to self-correct after expansion. (d) Final CBCT rendering of the amount of space that was actually created using a bone-borne expander

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Fig. 11  Notice how the pretreatment panorex does not give the full picture of the relationship between the right canine crown and lateral incisor root for the patient in Figures 8, 9, 10

mocking up treatment with palatal expansion as described in the earlier cases. Due to the history of chronic sinus congestion, the family opted to have her treated with bone supported expansion of the maxilla in combination with clear aligners to expand the lower arch and coordinate the arches after expansion. Note the healthy alveolar space between the teeth, and lack of flaring in Fig.  13b posttreatment. Posttreatment improvement in her sinuses and nasal congestion is evident in Fig. 14. It is important to note that no single method is perfect and there is no “one size fits all” when it comes to determining

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Fig. 12  Teen case of bone supported expansion mock-up. (a) Initial anatomodel showing mild discrepancies in tooth alignment. (b) An option was mocked up of moving the teeth with clear aligners without  any skeletal expansion. (c) Occlusal view of lower arch before uprighting. (d) Lower arch decompensated and measurement taken

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from central groove of each first molar. (e) Occlusal view of upper arch showing width discrepancy between lower uprighted measurement and upper mesiopalatal cusps. It was determined that 4–5 mm of expansion was needed. (f) Final frontal view of mock-up of expansion (pure skeletal)

The Transverse Dimension: CBCT Treatment Planning in Growing Children

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Fig. 13  CBCT rendering of patient in Fig. 12, (a) Initial frontal view. (b) Final frontal view following bone supported expansion and clear aligners: note healthy space between roots and lack of flaring of the posterior teeth

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Fig. 14  Sinuses of patient in Fig. 12. (a) Before treatment the patient had a lot of sinus filling. (b) After bone supported expansion, her sinuses were much clearer

the amount of expansion needed. For example, for individuals who have a significant amount of crowding or if there is a major concern of impacting canines, it may be necessary to expand more than the amount necessary to ensure enough space is available. Even when expanding to the desired measurement, regardless of which appliance is used, it is wise to overdo the expansion by 1–2  mm in order to account for relapse that occurs. The authors are aware that many practitioners will not use the Anatomage software. More CBCT validation studies are

needed to develop a good CBCT analysis for the transverse dimension. When evaluating the coronal sections at the level of the first molars, the maxilla should be wider than the mandible in the mid alveolar region. A measurement that can be useful is the “outer differential” as described by Simontacci et  al. [94]. They used a combination of the Ricketts transverse analysis [95, 96] and the Andrews transverse analysis [97]. Andrews proposed, in the six elements of orofacial harmony, that mandibular width is naturally optimal in most patients. They determined that maxillary width should be

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5 mm greater than the mandibular width when the first permanent molars are centered and upright in the alveolus. The patient is skeletally deficient in the transverse dimension if the difference between maxillary and mandibular width is less than 5 mm. Simontacci and colleagues used the difference between the maxillary width at level of the apex of the first molars and the mandibular width at the level of the “mucogingival junction” on CBCT coronal sections as the reference points. They determined that the maxillary width should be 5  mm wider than the mandible at this point. Figure 14 shows these measurements applied to the patient in Fig. 12.

Implications for Adult Orthodontic Patients There are many adult patients seeking care for recurring crowding after prior orthodontic treatment (many of whom have had extraction of bicuspids), who present with normal gingiva but with gingival recession. The majority of these cases present with a transverse skeletal discrepancy. Great care must be taken to evaluate the quality of the periodontal support and examine the compensations. When treatment

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Fig. 15  Superimpositions of bone-expansion versus dental expansion in two teenage females. (a) Superimposition of the maxilla showing the results of a bone-borne expander. The blue indicates the final time point and the white indicates initial. It can be appreciated that there was skeletal change in the maxilla. (b) Superimposition of the maxilla showing the results of a tooth-borne expander in a similar aged patient over a similar period of time (expanded at another office). The blue indicates

C. Ferrari

goals can only be met by decompensating the dentition, SFOT can increase the boundaries by adding more buccal bone and reducing attachment loss. This does not change the basal bone but can be indicated to change the arch form in mild transverse discrepancies or for correcting lower compensations, combined with bone supported expansion of the maxilla, with or without surgical assistance. When patients are viewed through the lens of airway health, increasing tongue space may be one of the goals of treatment. Some adult patients will tolerate expansion of the arches through dentoalveolar “bending.” Unfortunately, this “bending” capacity is variable and, in our practice, we are seeing a “rash” of adult patients seeking treatment to un-do treatment provided with good intentions but not enough attention to periodontal health, resulting in severe tipping, severe periodontal recession, and even tooth loss. It is our hope that providers will: (1) Respect the periodontal structures with attention to existing bone support, periodontal phenotype, and amount of desired expansion, and choose appliances wisely, understanding the long-term implications of their treatment choices and (2) Evaluate the transverse dimension and treat patients earlier to mitigate this problem in the future (Fig. 15).

b

the final time point and the white indicates initial. Notice that the movement was all dental as opposed to skeletal. (c) Coronal view of superimposition of bone-borne expansion. Note wider maxillary/midfacial complex including the alveolus, nasal, sinus, and zygomatic areas. (d) Coronal view of superimposition of tooth-borne expansion, note the tipping of teeth and no expansion of the nasal cavity

The Transverse Dimension: CBCT Treatment Planning in Growing Children

c

143

d

Fig. 15 (continued)

Summary The maxillary component of the craniofacial complex is often narrower than ideal leading to crowding, dental compensations lending to periodontal issues, reduced tongue space, potentially reduced airflow through the nose, and reduced esthetics due to large buccal corridors. It is not possible to accurately assess the skeletal discrepancy clinically, with models, or with traditional pan/ceph images. CBCT imaging allows for far greater accuracy in diagnosis and treatment planning. Treating the transverse discrepancy early allows for a greater component of skeletal correction. In the late mixed or early permanent dentition, it may be preferable to use a bone-borne expander to affect a skeletal change, improve nasal airflow, and reduce the negative side effects of tooth-borne expanders. Acknowledgment  Special thanks to Kaitlin Marsh, DDS, MS, for her invaluable help in the creation of the figures in this chapter. Thanks to Dr. Sean Carlson for introducing  the Anatomage treatment planning process.

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Goal-Oriented Treatment Planning with Corticotomy-Facilitated Orthodontics Rebecca Bockow

Introduction Patients who seek orthodontic treatment are present with dental crowding and/or with skeletal discrepancies. When patients with malocclusions resulting from underlying skeletal discrepancies desire treatment, we as orthodontists offer a spectrum of treatment options based on the clinical diagnosis and desired final outcome. As Dr. Morton Amsterdam wrote, for every malocclusion there are multiple treatment modalities but only one correct diagnosis [1]. When the etiology for the malocclusion is skeletally based, a patient’s treatment options include either a combination of orthodontics and orthognathic surgery or orthodontic “camouflage” treatment, including extractions and interproximal reduction [2, 3]. Orthodontists rely on comprehensive orthodontic records, including clinical presentation, periodontal condition, restorative needs, dental models, and radiography including threedimensional cone beam computed tomography (CBCT) imaging, to help decide which treatment options and modalities are most appropriate for each patient. Using these diagnostic records, a problem list is generated, a diagnosis is developed, and clear treatment objectives are outlined [2, 3]. These objectives will help define which treatment strategies may be appropriate to achieve the desired outcomes. When considering the appropriate treatment modality, an orthodontist must take into consideration not only the predictability of the treatment plan, but also any and all adverse sequelae. Dr. Proffit and Dr. Vanarsdall both published on the predictable range and limit of orthodontic tooth movement with brackets and wires alone [4, 5]. They further illustrated that dentofacial orthopedics combined with growth allow for a wider range of tooth position changes, due in part to the growth and development of skeletal and dento-alveolar R. Bockow (*) Private Practice Limited to Orthodontics and Periodontics, Seattle, WA, USA Department of Orthodontics, University of Washington, Seattle, WA, USA

structures. We now know that airway and tongue position also contribute to the growth potential and growth patterns of the skeletal bases. Finally, the largest predictable tooth movement results from a combination of traditional orthodontics with orthognathic surgery [4, 5]. The important concept Drs. Proffit and Vanarsdall convey is that there are biologic limits to where orthodontics alone can move teeth. As many orthodontists and periodontists have seen, the teeth, bone, and periodontium can all be lost to some extent if such biologic limits are not understood and respected [6–9]. The biologic limits of orthodontic tooth movement are defined by the pretreatment alveolar bone and the surrounding soft tissues [6–8]. Moving teeth outside of the alveolus can result in bony dehiscences and fenestrations [9, 10]. Gingival recession can occur as a consequence, either during, immediately following, or in the years after treatment [11–13]. Adverse sequelae of such tooth movements may also include root resorption, cessation of tooth movement, horizontal bone loss, and a higher risk of orthodontic relapse [14–17]. CBCT scans illuminate the presence of dehiscences, fenestrations, and the relationship between teeth and their surrounding alveolar housing in three dimensions [18]. Three-dimensional radiographic information helps identify the presence of a preexisting narrow alveolar arch (in a buccolingual dimension) which may house large or broad tooth roots. These anatomic discrepancies may be considered risk factors for future recession and/or bone loss, particularly in the event of unplanned orthodontic tooth movement [11–13, 19]. While the presence of a dehiscence or fenestration in the bone does not automatically translate clinically into gingival recession, it places a patient at greater risk for developing recession over time [20, 21]. The use of three-dimensional CBCT data helps identify which patients seeking orthodontic correction can be treated successfully with orthodontic camouflage. As in all treatment planning, one must perform a virtual treatment objective (VTO) set-up in order to determine the ideal final position of the teeth relative to the skeletal base once treat-

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_11

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ment is complete [22]. A VTO can be formulated simply by drawing the proposed tooth movement on a printed image of a patient’s skeletal base in order to visualize the proposed tooth movement. If the three-dimensional CBCT data reveals that sufficient alveolar bone is present to support the proposed tooth movement, then camouflage treatment, including interproximal tooth reduction, extractions, and the use temporary anchorage devices (TADs) for enmasse movement may be an appropriate treatment modality. If the VTO reveals that the final ideal tooth position will place the roots outside of the available alveolar bone, as determined by the CBCT, then an advanced surgical treatment modality may be an appropriate treatment option to consider.

 reatment Planning with the Ideal Tooth T Position Relative to the Face and Skeletal Base I deal teeth Positions—Three-Dimensional Goals Orthodontic tooth movement goals include placing the teeth in an ideal position relative to the skeletal base, relative to the face, centered in the alveolar bone, and at a proper angulation and inclination to support an ideal occlusal scheme. Ideal orthodontic treatment plans start with ideally positioning the central incisor in three planes of space. All of the following clinical guidelines assume an ideally sized and shaped central incisor. A given patient is examined extra orally in an adjusted natural head position, as viewed from a lateral aspect.* The patient is photographed in this position, then asked to smile. A photograph is once again obtained using the smiling posture (Fig.  1). A lateral cephalometric radiograph or a CBCT is also taken at the same adjusted natural head position. *A natural head position is when a patient is standing using a neutral posture and is comfortably looking straight ahead, either at a distant object at the same height as the eyes or gazing into a mirror. An adjusted natural head position is when the clinician slightly adjusts the patient’s head in order to accurately capture the head position without the patient compensating or posturing [23]. Using a printed or digital copy of the smiling patient photograph, a true vertical line is drawn perpendicular from the most prominent part of the patient’s forehead (soft tissue glabella). Ideally, the center of the clinical crown of the maxillary central incisor should rest along this line. This vertical line sets the anterior/posterior goal for the crown of the central incisor relative to the patient’s face (Fig. 2) [24, 25]. The vertical goal of the central incisor is determined by the wet-dry line of the upper lip. The center of the clinical crown

Fig. 1  Lateral profile photograph with the patient smiling in adjusted natural head position

of the central incisor should ideally rest along the wet-­dry line of the upper lip when the lips are at rest (repose) [26]. Proper root angulation for the maxillary central incisor is important for phonetics, anterior disclusion, and light-­reflection (esthetics). The ideal angulation of the maxillary central incisor is approximately 56° from the occlusal plane [26]. Finally, the ideally positioned maxillary central incisor must be surrounded by alveolar bone for stability and soft tissue support [27, 28]. Once the ideal position of the central incisor is established, the lower incisors must ideally couple with the upper incisors with 3 mm of overjet and overbite. Once again, the lower incisors should be surrounded with alveolar bone for long-term stability. [29] (Fig. 3). The transverse dimension of both maxillary and mandibular arch forms is important for dental stability, periodontal stability, establishment of adequate tongue space and, subsequently, airway space. Ideal transverse dental goals can be assessed at the level of the first molars. Dentally, our goals consist of the maxillary palatal cusp should be centered in the central fossa of the mandibular molar. The maxillary and mandibular teeth should be upright in the alveolar bone with

Goal-Oriented Treatment Planning with Corticotomy-Facilitated Orthodontics

Fig. 2  Soft tissue glabella is identified, a straight vertical line is drawn, and this line determines the anterior-posterior goal limit for an ideally positioned maxillary central incisor relative to the patient’s face. The ideal vertical orientation of the maxillary central incisor is to align the center of the clinical crown with the wet-dry line of the upper lip

proper buccal over jet of the maxillary buccal cusps over the mandibular buccal tooth surface (Fig.  4) [29]. Given the average buccal/lingual dimensions of the molars, the maxillary arch should be approximately 5 mm wider than the mandibular arch. Measurements of the basal alveolar bone can be approximated at the level of the mucogingival junction (MGJ) at the location of the first molars. A measurement taken from MGJ to MGJ at the level of the maxillary first molars should be 5 mm wider than the measurement taken from MGJ to MGJ of the mandibular molars [25]. If one has a CBCT, this same measurement can be taken using a coronal slice at the level of the first molars. Measurements can be taken from MGJ-MGJ or from pulp chamber to pulp chamber. As long as the measurement point is consistent, the transverse goal remains to achieve a maxillary arch that is 5 mm wider than the mandibular arch [30]. The teeth should be upright and centered in the alveolus, and the upper and lower teeth should intercuspate in order to allow the teeth to be loaded along their long axes (Fig. 5) [31].

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Fig. 3  The virtual treatment objectives are translated from the photograph to the lateral cephalometric radiograph. The original position of the incisors is traced out. Ideal tooth positions are identified and overlaid. Now the clinician can determine if traditional orthodontic tooth movement can predictably move the teeth into their ideal position, or if other treatment modalities such as bone augmentation or orthognathic surgery must be considered

Fig. 4  The palatal cusps of the maxillary first molars should be positioned in the central fossa of the mandibular molars. These teeth should be centered in the alveolar bone and loaded along their long axis

When treatment planning was given to a patient, one must first identify where the teeth are, then where they need to be moved for an ideal result. The next question becomes—is there available bone to support such an idealized tooth movement? If the answer is yes, one can proceed with traditional

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Fig. 5  The mucogingival junction (MGJ) can act as a marker of the basal alveolar bone. Measurements made from MGJ to MGJ at the level of the first molars serve as a way to measure the transverse. Ideal tooth positions as viewed from the transverse include upright teeth centered in the alveolar bone with palatal cusps of the maxillary molars resting in the central fossa of the mandibular molars. Notice also the absence of the curve of Wilson

orthodontics. If the answer is no, one must consider moving the jaws (orthognathic surgery). In instances, where there is inadequate alveolar bone, but the discrepancy is minor, or in the event that a patient declines orthognathic surgery, we can now augment the alveolar bone with selective alveolar grafting in conjunction with orthodontic tooth movement in order to achieve our idealized tooth movement goals.

Corticotomy-Facilitated Orthodontics as a Treatment Alternative Traditionally, the only treatment option for patients requiring tooth movement beyond the scope of orthodontic camouflage treatment was a combination of orthodontics and orthognathic surgery [32, 33]. Procedures such as surgically assisted rapid maxillary expansion (SARPE), three-piece LeFort maxillary surgeries, and mandibular advancements and set backs are all incorporated into orthodontic treatment plans when indicated. Unfortunately, not all orthodontic patients are candidates for orthognathic surgery. Patients may decline orthognathic surgery due to fear, cost, lifestyle, or underlying health issues that prevent them from undergoing general anesthesia. We now have an effective treatment option to offer borderline surgical orthodontic patients. Corticotomy-facilitated orthodontic treatment modalities have been published as case reports in the dental literature since the 1950s, with additional publications surfacing in the late 1980s and early 1990s [34–37]. In 2001, the Wilcko brothers published a combined treatment modality consisting of an in-office periodontal surgical procedure combined

with orthodontic tooth movement [38–40]. Their described method included full thickness mucoperiosteal flaps and decorticating the buccal and lingual/palatal sides of the alveolar bone with a round bur to create bleeding points. They then added hydrated particulate bone graft material against the decorticated alveolar bone, under the periosteum. The goal of their surgical intervention was to induce a localized osteopenia and rapid bone turnover [38]. Their goals also included surrounding the teeth with additional bony support, augmenting the range of orthodontic tooth movement and aiding in long-term post-orthodontic stability [16, 38]. Following the surgical procedure, the teeth were rapidly orthodontically moved into the grafted bone. Their published protocol includes seeing the patient every 2 weeks for adjustments in order to maintain the “bone activation,” rapid bone turnover, and rapid tooth movement. While numerous publications, including studies and case reports, have highlighted accelerated tooth movement when combining a surgical insult with orthodontic therapy, some have called into question the need for periodontal flap procedures solely for the purposes of speed [41]. Variations on the original “Wilckodontics” or “Surgically Facilitated Orthodontic Treatment (SFOT)” treatment have been published, including flapless “piezocision” and transmucosal micro-osseous perforations [42–44]. A recent publication reports that the greater the surgical insult, the greater the localized osteopenia, alveolar decalcification, and more rapid the tooth movement [45]. Two recent systematic reviews conclude that corticotomy-facilitated orthodontics is safe for the oral tissues and results in a transient phase of accelerated orthodontic tooth movement [46, 47]. Various publications have additionally described benefits of this procedure including a thickening of the supporting alveolar bone and periodontal soft tissue following surgically facilitated orthodontics [46, 48, 49]. Patient morbidity and cost are considered drawbacks to the SFOT procedure [41]. While these remain important concerns for all treatment plans, additional patient desires and clinical findings must be taken into account. Frequently, adult orthodontic patients require soft tissue augmentation prior to or following orthodontic therapy due to preexisting gingival recession. By employing well-planned timing and sequencing, recession defects can be simultaneously resolved by combining SFOT and gingival augmentation. An orthodontist can place brackets, the soft tissue can be augmented, and the SFOT procedure can be completed in one simultaneous surgical procedure. The orthodontist can then take advantage of the rapid bone turnover as well as the increased range of tooth movement possibilities. Such patients would have paid for and received gingival grafting regardless. Now the patient also receives the added benefit of faster and greater tooth movement. In such cases, SFOT will not significantly add to the total treatment cost or patient morbidity.

Goal-Oriented Treatment Planning with Corticotomy-Facilitated Orthodontics

Furthermore, for patients who are borderline candidates for orthognathic surgery, one may argue that an in-office periodontal procedure including selective alveolar decortication and bone augmentation may be less costly and less invasive to a patient than a hospital stay. Additionally, it saves a patient from the associated surgical risks and post-operative morbidity encountered with intubation and orthognathic surgery.

A Segmental Approach The original “Wilckodontics” treatment protocol as published by Wilcko et al. included buccal and lingual full thickness mucogingival flaps and decortication of both alveolar walls in both arches [38]. This renders a great deal of trauma to the bone and soft tissue, and may be warranted for some treatment plans. A segmental SFOT approach may be indicated in cases where bone augmentation is only required in the direction of proposed tooth movement. Such a conservative approach decreases patient cost and morbidity, while still allowing for an increased range of tooth movements. Clinical examples may include a class II skeletal relationship treated non-surgically where bone augmentation between the mandibular canines may allow for improved incisor coupling and a decreased mental-labial fold. Other case examples are patients with narrow maxillae and end-to-end buccal overjet posteriorly. If these patients have preexisting buccal recession, they may either be candidates for surgically assisted rapid palatal expansion (SARPE), or for buccal maxillary SFOT to widen the maxillary archform. While controlled clinical trials have yet to quantify the precise limits of tooth movement with SFOT, predictable success has been observed clinically. Successful cases have thus far achieved approximately 5 mm or more of dento-alveolar expansion bilaterally and up to 6 mm of mandibular incisor proclination with the employment of segmental decortication and bone grafting.

Clinical Applications Clinically, orthodontic diagnosis for SFOT candidates remains the same as for all orthodontic patients. Orthodontic and skeletal problems are assessed based on severity and treatment needs, utilizing comprehensive orthodontic records. Clinical findings and patient desires are considered in the treatment planning decisions. When malocclusions are severe enough that they cannot be treated with orthodontic camouflage but are not so severe as to warrant orthognathic surgery, SFOT may be a viable treatment option (Fig. 1). Patient selection is of the utmost importance for the SFOT treatment plan. In addition to using a VTO in the treatment planning phase to determine whether SFOT is indicated, a

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thorough patient health history can further influence one’s choice of treatment modality. Patients taking certain medications such as long-term bisphosphonate use, corticosteroid or NSAID therapy, or blood thinners such as coumadin are not candidates. Patients with bleeding disorders as well as immunocompromised patients are also not candidates for this procedure. Additionally, patients must be able to accommodate frequent visits to the orthodontist (every 2–3 weeks). The literature shows that, in an animal model, the increased bone turnover lasts approximately 4 months in duration [50, 51]. In humans, Frost reported that the regional acceleratory phenomenon (RAP) can last anywhere from 6 to 24 months [52, 53]. Consequently, patients must return to the orthodontist approximately every 2 weeks for the first 4–6 months or longer after the decortication procedure in order to maximize both tooth movement and bone remodeling. Patients must be informed of this during the treatment planning stages. Without the opportunity for continuous bone activation, the positive effects that accompany the surgical intervention may be lost. Patients and treating clinicians often ask what happens to the bone graft material after the surgery. Does this bone turn into the patient’s own bone? Or do the bone graft particles simply become encapsulated within the soft tissue? The Wilcko brothers have published re-entry findings on patients they treated. These case reports demonstrated that the surgery successfully corrected preexisting dehiscences and fenestrations. The histologic analysis of bone samples from these patients further revealed that the bone graft particles became incased in native bone upon healing and maturation [39, 54]. In their 2001 paper, Araújo, et al. demonstrated that, in a dog model, teeth were successfully moved into sites grafted with Bio-Oss particles [55]. Their study showed that the Bio-Oss particles were degraded and eliminated from the alveolar ridge in the direction of tooth movement, but remained on the tension side [55]. Based on this information as well as clinical observations, one can assume that the bone graft particles are being incorporated into the patient’s own alveolar bone in the direction of tooth movement.

Case Example Initial Presentation A 28-year-old female patient presented with a chief complaint of “I don’t like my smile and my open bite.” Her health history was significant for occasional social cigarette smoking. She reported that her teeth never touched in the front of her mouth. Prior to her initial presentation, she had seen two orthodontists and an oral surgeon, all of whom informed her that the only treatment option was a combination of orthognathic surgery and orthodontics. Due to fear, the patient declined all treatment options requiring a maxillary LeFort surgical procedure. (Fig. 6a–e).

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Fig. 6 (a) Full face smiling of Class III dentofacial disharmony malocclusion patient with midface deficiency. (b) Lateral profile of Class III dentofacial disharmony malocclusion patient with midface deficiency. (c) Retracted view of dentition. Patient in centric occlusion. Note ante-

rior open bite, gingival recession in all four quadrants, and dental crowding. (d) Left lateral view of dentition in centric occlusion. (e) Right lateral view of dentition in centric occlusion

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Problem List mandibular incisors was for them to couple with the ideally The patient possessed a high mandibular plane angle (SN-­ positioned maxillary incisors (Fig. 8). Furthermore, a coroMP = 44°) and a prominent hard and soft tissue pogonion. nal slice of the full-head CBCT revealed the extent of the She had a history of multiple dental restorations, a complete maxillary transverse deficiency (Fig. 9). dentition including her third molars, a skeletal Class III patIn order to execute the proposed tooth movement as demtern (Witts Appraisal = −9.9, ANB = −5.8°) with an anterior onstrated in the VTO, an ideally positioned maxillary central open bite, a deficient maxilla in all three dimensions, four incisor would need to be extruded and protracted beyond the quadrants of facial gingival recession, left temporo-­ patient’s available alveolar bone, as seen in the CBCT [4, 5]. mandibular joint clicking with no associated pain, lingually The maxillary arch required 4 mm of expansion in order for inclined mandibular posterior teeth, and minor mandibular the palatal cusps of the maxillary molars to rest in the central and moderate maxillary crowding (Fig. 6c–e). No CRO/MIP fossae of the mandibular molars when the mandibular molars shift was noted. The heads of both condyles were corticated were positioned upright within the alveolar bone. All idealas observed in the pretreatment CBCT and her joints were ized tooth movements, if performed with brackets and wires deemed stable. alone, would have pushed the tooth roots outside of the alveolar housing, as visualized in the VTO. Favorably, most of Goals of Treatment the large idealized tooth movements were isolated to the A VTO was generated from the patient’s lateral cephalo- maxillary arch, and all in a buccal direction. metric radiograph, which allowed us to visualize the proposed ideal tooth movements (Figs. 7 and 8). Treatment Treatment Plan and Therapy goals were planned around an ideally positioned maxillary The goals of orthodontic tooth movement in the mandible central incisors in three planes of space [46]. The goal was included uprighting the mandibular teeth to a more stable posifor the mid-facial point of the central incisor to lie along a tion in the alveolus, combined with conservative interproximal vertical plane coincident with the most prominent portion of reduction to resolve the dental crowding. Once the teeth in the the patient’s forehead [46]. The vertical limit of the maxil- mandibular arch were idealized, they would serve as a template lary central incisor was planned so that the middle of the for the maxillary final tooth position, both in the transverse and crown would be at the same horizontal level as the wet-dry A/P dimensions. The goals of tooth movement in the maxillary line of the upper lip [28]. The ideal root torque was set to arch included transverse expansion and anterior extrusion. All 56.8 ± 3° from the occlusal plane, as outlined by Drs. Arnett proposed maxillary tooth movement was in the buccal direcand Gunson [32, 56]. The goal for the final position of the tion. Therefore, only the buccal maxilla required segmental decortication and bone graft augmentation.

Fig. 7  A lateral cephalometric radiograph depicts the extent of the skeletal malocclusion, including the deficient maxilla, high mandibular plane angle, prominent chin, and anterior open bite

Fig. 8  A virtual treatment objective drawing reveals that the ideally positioned maxillary central incisor would position the apex of the tooth outside of the maxillary alveolar housing

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Fig. 11  Leveling and aligning is complete, and the patient is ready for her periodontal surgery

Fig. 9  A coronal slice of the full-head CBCT reveals the extent of the maxillary transverse discrepancy. In order for the palatal cusps of the maxillary molars to rest within the central fossae of the mandibular molars, the maxillary arch required at least 4 mm of expansion

Fig. 12  A full-thickness flap was utilized on the buccal only of the maxillary arch

Fig. 10  Leveling and aligning were completed prior to the corticotomy and bone augmentation procedure

Leveling and aligning were completed early during treatment in order to progress to a rectangular nitinol wire (Fig. 10). Large bodily tooth movements were to be initiated immediately following the corticotomy procedure, allowing the alveolus and teeth to remodel to the desired new position during the period of high bone turnover and subsequent healing, and such movements would require a larger archwire for strength and three-dimensional control (Fig. 11). Following

leveling and aligning, a full thickness flap was reflected and alveolar corticotomies performed along the buccal surfaces of the maxilla, spanning from molar to molar (Figs. 12, 13, and 14). The alveolus was grafted with re-hydrated sterile particulate freeze-dried human bone allograft, and the flaps were repositioned and sutured to place. Healing was uneventful. Ten days following the in-office procedure, maxillary protraction and extrusion began with the use of full-time Class III elastics, combined with anterior vertical elastics at night. The maxillary archwire was expanded in order to obtain the desired transverse expansion. Progression to a full-sized stainless steel archwire helped maintain proper torque. The patient was seen every 2 weeks in order to assess the treatment progress and to make any necessary orthodontic changes. Large tooth movements occurred efficiently within the weeks following the surgery. The final finishing and detailing stages of the patient’s treatment were completed within the same time frame as with any orthodontic case (Figs. 15, 16, 17, 18, and 19).

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Fig. 13  The alveolar bone was decorticated and grafted from second molar to second molar on the buccal surface only

Fig. 16  The maxillary arch was successfully expanded

Fig. 14  The buccal surface of bone was decorticated prior to bone augmentation

Fig. 17  The mandibular arch crowding was resolved and the mandibular teeth were centered within the alveolar housing

Fig. 15  At the completion of orthodontic tooth movement, all treatment goals have been achieved

Fig. 18  All occlusion goals including proper intercuspation, class I molar and canine relationships and proper overbite and over jet were achieved

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Fig. 19  All occlusion goals including proper intercuspation, class I molar and canine relationships and proper overbite and over jet were achieved Fig. 20  All proposed ideal tooth movements were achieved while maintaining teeth within the alveolar housing

Results Tooth movement goals as outlined in the original treatment plan were achieved at the end of treatment (Fig.  20). No extra-oral skeletal changes such as mid face or chin projection alterations were noted between pre- and post-treatment records as no orthognathic surgery was performed (Fig. 21a– c). Total treatment was completed in 13 months. The success seen in this case, however, is not from the speed of orthodontics, but from the dramatic range of tooth movements achieved without adverse sequelae to the teeth and periodontium. In this patient, only maxillary buccal bone grafting was

utilized, minimizing the surgical intervention. The final photographs reveal an area of slight marginal gingival recession around the upper left canine. Proper surgical soft tissue handling, including apical flap release, coronally advanced flaps, and even simultaneous soft tissue grafting can all help prevent the mild recession defects that were seen in this example. Many patients are now being treated with a combination of both hard and soft tissue grafting materials, thus changing the tissue thickness, correcting recession defects, and further preventing future recession. All teeth, occlusal and soft tissue changes remained stable at the patient’s 1-year retention visit.

Goal-Oriented Treatment Planning with Corticotomy-Facilitated Orthodontics Fig. 21 (a–c) No facial or skeletal changes are noted following treatment completion

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Conclusions Much of what we know regarding this combined treatment protocol has been derived from case reports and clinical experiences and therefore many surgical and clinical questions remain unanswered. The potential range of tooth movement and long-term stability with this combined treatment need to be further defined by future well-designed studies

and clinical trials. We have seen, however, that orthodontics combined with selective alveolar decortication and bone grafting can lead to dramatic outcomes and, when appropriate, may be an alternative for borderline orthognathic surgical candidates. Clear treatment objectives, proper case selection, goal-oriented orthodontic mechanics, sequencing, and timing all play a role in the successful outcomes of these cases.

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Individual patient malocclusions and skeletal deformities all fall within a spectrum from less to more severe. As such, our orthodontic and surgical treatment decisions also fall within a spectrum. Numerous factors will influence our treatment decisions, including the patient’s pre-treatment periodontal condition. This diagram highlights many of the pre-treatment clinical questions orthodontists are faced with. The answers to these questions and their severity may lead to one treatment modality over another.

References 1. Amsterdam M. Periodontal prosthesis. twenty-five years in retrospect. Alpha Omegan. 1974;67(3):8–52. 2. Ackerman JL, Nguyen T, Proffit WR.  The decision-making process in orthodontics. In: Graber LW, Vanarsdall RL, Vig KW, editors. Orthodontics. 5th ed. Philadelphia, PA: Mosby Elsevier; 2012. p. 3–58. 3. Sarver D, Yanosky M.  Special considerations in diagnosis and treatment planning. In: Graber LW, Vanarsdall RL, Vig KW, editors. Orthodontics. 5th ed. Philadelphia, PA: Mosby Elsevier; 2012. p. 59–98. 4. Vanarsdall RL, Musich DR. Adult interdisciplinary therapy: diagnosis and treatment. In: Graber LW, Vanarsdall RL, Vig KW, editors. Orthodontics. 5th ed. Philadelphia, PA: Mosby Elsevier; 2012. p. 843–96. 5. Vanarsdall RL, Musich DR.  Adult orthodontics: diagnosis and treatment. In: Graber LW, Vanarsdall RL, editors. Orthodontics. 3rd ed. Philadelphia, PA: Mosby Elsevier; 2000. p. 908. 6. Yagci A, Veli I, Uysal T, et al. Dehisence and fenestration in skeletal Class I, II and III malocclusions assessed with cone-beam computed tomography. Angle Orthod. 2012;82(1):67–74. https://doi. org/10.2319/040811-­250.1. Epub 2011 Jun 22 7. Gracco A, Luca L, Bongiorno MC, et  al. Computed tomography evaluation of mandibular incisor bony support in untreated patients. Am J Orthod Dentofac Orthop. 2010;138(2):179–87. 8. Ackerman JL, Proffit WR. Soft tissue limitations in orthodontics: treatment planning guidelines. Angle Orthod. 1997;67(5):327–36. 9. Wehrbein H, Fuhrmann RAW, Diedrich PR. Periodontal conditions after facial root tipping and palatal root torque of incisors. Am J Orthod Dentofac Orthop. 1994;106(5):455–62. 10. Handelman CS.  The anterior alveolus: its importance in limiting orthodontic treatment and its influence on the occurrence of iatrogenic sequelae. Angle Orthod. 1996;66:95–109. 11. Renkema AM, Fudalej PS, Renkema AA, et  al. Gingival labial recessions in orthodontically treated and untreated individuals: a case-control study. J Clin Periodontol. 2013;40(6):631–7. 12. Lund H, Grondahl K, Grondahl HG. Cone beam computed tomography evaluations of marginal alveolar bone before and after orthodontic treatment combined with premolar extractions. Eur J Oral Sci. 2012;120(3):201–11. 13. Renkema AM, Fudalej PS, Renkema A, et al. Development of labial gingival recessions in orthodontically treated patients. Am J Orthod Dentofac Orthop. 2013;143(2):206–12. 14. Ahn HW, Moon SC, Baek SH. Morphometric evaluation of changes in the alveolar bone and roots of the maxillary anterior teeth before and after en masse retraction using cone-beam computed tomography. Angle Orthod. 2013;83(2):212–21. 15. Wehrbein H, Bauer W, Diedrich P.  Mandibular incisors, alveolar bone, and symphysis after orthodontic treatment. A retrospective study. Am J Orthod Dentofac Orthop. 1996;110(3):239–46.

R. Bockow 16. Rothe LE, Bollen AM, Little RM, et  al. Trabecular and cortical bone as risk factors for orthodontic relapse. Am J Orthod Dentofac Orthop. 2006;130(4):476–84. 17. Ten Hoeve A, Mulie RM. The effect of antero-postero incisor repositioning on the palatal cortex as studied with laminagraphy. J Clin Orthod. 1976;10:804–22. 18. Nahm KY, Kang JH, Moon SC, et  al. Alveolar bone loss around incisors in Class I bidentoalveolar protrusion patients: a retrospective three-dimensional cone beam CT study. Dentomaxillofac Radiol. 2012;41(6):481–8. 19. Richman C. Is gingival recession a consequence of an orthodontic tooth size and/or tooth position discrepancy? “A paradigm shift”. Compend Contin Educ Dent. 2011;32(4):e73–9. 20. Artun J, Krogstad O. Periodontal status of mandibular incisors following excessive proclamation. A study in adults with surgically treated mandibular prognathism. Am J Orthod Dentofac Orthop. 1987;91(3):225–32. 21. Flores-Mir C.  Does orthodontic treatment lead to gingival recession? Evid Based Dent. 2011;12(1):20. 22. Fish LC, Epker BN. Surgical-orthodontic cephalometric prediction tracing. J Clin Orthod. 1980;14:36–52. 23. Lundström A, Lundström F, Lebret LM, et al. Natural head position and natural head orientation: basic considerations in cephalometric analysis and research. Eur J Orthod. 1995;17:111–20. 24. Andrews LF, Andrews WA. Element I. Andrews J Orthod Orofac Harmony. 2000;1:iv. 25. Andrews LF, Andrews WA.  Six elements diagnostic records. Andrews J Orthod Orofac Harmony. 2001;2:15–20. 26. Arnett GW, Jelic JS, Kim J, Cummings DR, Beress A, Worley CM Jr, Chung B, Bergman R. Soft tissue cephalometric analysis: diagnosis and treatment planning of dentofacial deformity. Am J Orthod Dentofacial Orthop. 1999;116(3):239–53. 27. Cao L, Zhang K, Bai D, Tian Y, Guo Y. Effect of maxillary incisor labiolingual inclination and anteroposterior position on smiling profile esthetics. Angle Orthod. 2011;81:121–9. 28. Andrews WA. AP relationship of the maxillary central incisors to the forehead in adult white females. Angle Orthod. 2008;78:662–9. 29. Andrews LF.  The six keys to normal occlusion. Am J Orthod. 1972;62:296–309. 30. Andrews LF, Andrews WA. The six elements of orofacial harmony. Andrews J Orthod Orofac Harmony. 2000;1:36–8. 31. Ronay V, Miner RM, Will LA, Arai K.  Mandibular arch form: the relationship between dental and basal anatomy. Am J Orthod Dentofac Orthop. 2008;134:430–8. 32. Arnett GW, Gunson MJ. Esthetic treatment planning for orthognathic surgery. J Clin Orthod. 2010;44(3):196–200. 33. Musich DR, Chemello PD. Orthodontic aspects of orthognathic surgery. In: Graber LW, Vanarsdall RL, Vig KW, editors. Orthodontics. 5th ed. Philadelphia, PA: Mosby Elsevier; 2012. p. 897–963. 34. Kole H. Surgical operations on the alveolar ridge to correct occlusal abnormalities. Oral Surg Oral Med Oral Pathol. 1959;12(5):515–29. 35. Anholm JM, Crites DA, Hoff R, et  al. Corticotomy-facilitated orthodontics. CDA J. 1986;14(12):7–11. 36. Gantes B, Rathbun E, Anholm M.  Effects on the periodontium following corticotomy-facilitated orthodontics. Case reports. J Periodontol. 1990;61:234–8. 37. Suya H.  Corticotomy in orthodontics. Heidelberg: Huthig Buch Verlag; 1991. 38. Wilcko WM, Wilcko MT, Bouquot JE, et  al. Rapid orthodontics with alveolar reshaping: two case reports of decrowding. Int J Periodontics Restorative Dent. 2001;21(1):9–19. 39. Wilcko MT, Wilcko WM, Pulver JJ, et al. Accelerated osteogenic orthodontics technique: a 1-stage surgically facilitated rapid orthodontic technique with alveolar augmentation. J Oral Maxillofac Surg. 2009;67(10):2149–59.

Goal-Oriented Treatment Planning with Corticotomy-Facilitated Orthodontics 40. Wilcko W, Wilcko MT. Accelerating tooth movement: the case for corticotomy-induced orthodontics. Am J Orthod Dentofac Orthop. 2013;144(1):4–12. 41. Mathews DP, Kokich VG. Accelerating tooth movement: the case against corticotomy-induced orthodontics. Am J Ortho Dentofacial Orthop. 2013;144(1):5–13. 42. Roblee RD, Bolding SL, Landers JM.  Surgically facilitated orthodontic therapy: a new tool for optimal interdisciplinary results. Compend Contin Educ Dent. 2009;30(5):264–75. 43. Keser EI, Dibart S.  Sequential piezocision: a novel approach to accelerated orthodontic treatment. Am J Orthod Dentofac Orthop. 2013;144(6):879–89. 44. Alikhani M, Raptis M, Zoldan B, et  al. Effect of micro-­ osteoperforations on the rate of tooth movement. Am J Orthod Dentofac Orthop. 2013;144(5):639–48. 45. McBride MD, Campbell PM, Opperman LA, et al. How does the amount of surgical insult affect bone around moving teeth? Am J Orthod Dentofac Orthop. 2014;145:S92–9. 46. Hoogeveen EJ, Jansma J, Ren Y.  Surgically facilitated orthodontic treatment: a systematic review. Am J Orth Dentofacial Orthop. 2014;145(4 Supp 1):S51–64. 47. Long H, Pyakurel U, Wang Y, et al. Interventions for accelerating orthodontic tooth movement: a systematic review. Angle Orthod. 2013;83(1):164–71. https://doi.org/10.2319/031512-­224.1. Epub 2012 Jun 21. Review 48. Shoreibah EA, Ibrahim SA, Attia MS, et  al. Clinical and radiographic evaluation of bone grafting in corticotomy-

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facilitated orthodontics in adults. J Int Acad Periodontol. 2012;14(4):105–13. 49. Ahn HW, Lee DY, Park YG, et  al. Accelerated decompensation of mandibular incisors in surgical skeletal Class III patients by using augmented corticotomy: a preliminary study. Am J Orthod Dentofac Orthop. 2012;142:199–206. 50. Sebaoun JD, Kantarci A, Turner JW, et al. Modeling of trabecular bone and lamina dura following selective alveolar decortication in rats. J Periodontal. 2008;79(9):1679–88. 51. Mostafa YA.  Mohamed Salah Fayed M, Mehanni S, et  al. Comparison of corticotomy-facilitated s standard tooth-movement techniques in dogs with miniscrews as anchor units. Am J Orthod Dentofacil Orthop. 2009;136(4):570–7. 52. Frost HM. The biology of fracture healing. An overview for clinicians, Part 1. Clin Orthop Relat Res. 1989;248:283–93. 53. Frost HM. The regional acceleratory phenomenon: a review. Henry Ford Hosp Med J. 1983;31(1):3–9. 54. Wilcko WM, Ferguson DJ, Bouquot JE, et al. Rapid Orthodontic Decrowding with Alveolar Augmentation: Case Report. World J Orthod. 2003;4(3):197–205. 55. Araújo MG, Carmagnola D, Berglundh T, Thilander B, Lindhe J.  Orthodontic movement in bone defects augmented with Bio-Oss. An experimental study in dogs. J Clin Periodontol. 2001;28(1):73–80. 56. http://www.arnettgunson.com/education-­m aterials/7-­s tep-­ cephalometric-­treatment-­plan (Accessed 27 Oct 2013).

Pre-surgical Orthodontic Therapy Drew McDonald

Orthodontic Diagnosis: The Foundation of Stable Treatment As orthodontic specialist, we are the trained at the highest level to be diagnosticians of the oral and masticatory system. When treatment planning each orthodontic case, many factors come into play as we design our ideal plan and outcome. At the foundational level, each patient’s temporomandibular joints, airways, tongue/orofacial muscle function, and alveolar bone phenotypes should all be analyzed prior to treatment to identify the etiology of the malocclusion and the factors that will cause instability of our final result. At the dentoalveolar level, we analyze skeletal anteroposterior, coronal, and transverse relationships of the jaws, as well as dental occlusal pattern, tooth orientations, and crowding to diagnose the patient’s specific malocclusion and decide  what needs to be corrected to achieve a functional result. And at esthetic level, we analyze tooth position, smile arc, smile width, and gingival display to dictate where we want to place the teeth for our final visual result. An ideal treatment plan addresses all three phases of foundation, function, and esthetics to obtain our goals of creating a visually pleasing smile with proper function and long-term stability. To achieve this, we must utilize advanced imaging technology to see our foundation and functional relationships of the jaws in all three planes. It is also often necessary to simulate our desired outcome to ensure our result is structurally achievable given each patient’s unique foundation and the bone through which teeth will be moved. To determine if a patient is a candidate for surgically facilitated orthodontic therapy, the utilization of CBCT imaging and treatment simulation technology should be used to diagnose discrepancies in the width, height, and phenotype of alveolar bone and to decide if bone augmentation is necessary.

D. McDonald (*) Private Practice limited to Orthodontics, Albuquerque, NM, USA e-mail: [email protected]

Foundational Diagnosis Before tooth-based decisions can be made to correct our patients’ malocclusions, diagnosis of the foundations of the TMJ, airway, soft tissues, and alveolar bone are imperative. Each of these areas have not only been tied to the development of malocclusion but have also been correlated with the persistence and relapse of malocclusion, especially after orthodontic treatment [1–4]. Simply stated, to develop treatment plans that ensure stable correction, we must address the underlying foundational conditions. Therefore, it is our responsibility to be astute diagnosticians of the foundation and often work in an interdisciplinary fashion to address the foundation and provide the highest level of treatment for our patients.

 emporomandibular Joint (TMJ) Foundation T Diagnosis Our temporomandibular joints are a very important source of maxillofacial development during growing years, as well as occlusal stability after active growth has ceased. Numerous studies have shown that issues with the TMJ complex contribute to the development of malocclusion, specifically retrognathia, asymmetries, and deficiencies of the mandible and maxilla [5] relapse patterns after orthodontic correction, premature tooth contacts, wear, and breakdown of the periodontium. It has also been shown that the more complex the malocclusion, the more likely TMJ pathology is involved [6]. Therefore, we must adequately diagnose our patient’s TMJ condition and stability before orthodontic treatment begins in order to understand the role that the joint played in the  development  of the malocclusion, and to design treatment to ensure TMJ stability long-term. To adequately diagnose our patients’ TMJ condition, we must not only rely on patient history and physical examination, but utilize appropriate advanced imaging to see the joint

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_12

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condition. Visualization of the TMJ complex needs to be done at the 3D level and CBCT allows us to see the hard tissue conditions of the joints and assess for not only condylar pathology, but abnormal growth and development of the condyles. Dr. Mark Piper has described norms of condylar and ramus development, as detection of pathology using CBCT imaging. In regard to proper development of the condyles, he has described the three parameters of condylar stability are that the condyle to fossa ratio should be ~66% for any patient when viewed from the sagittal aspect, the absolute condylar dimension should be 8 mm sagittal length and 20 mm coronal length, and that the condylar heads should be smooth when viewed from all aspects [7] (Fig. 1). These dimensions cannot be visualized with traditional pantographic and cephalometric radiographs and therefore CBCT should be the minimum standard at which we assess the condyle at the hard tissue level. If the condyles demonstrate issues with any of these three hard tissue parameters, there is a high likelihood of internal derangement, and therefore, and it is necessary to evaluate the soft tissue and inflammatory condition of the joint with MRI.  In regard joint stability from the MRI a

standpoint, Dr. Mark Piper has also described the parameters for proper disc position and occlusal stability. Ideally, the disc should be biconcave in shape and should have a posterior band at 1:00 o’clock when viewed from the sagittal, and the disc covering the medial and lateral poles when viewed from the coronal aspect (Fig.  2). Additionally, the MRI should be absent any inflammatory phenomena such as joint effusions, condylar edema, or soft tissue edema. If the MRI demonstrates deviations from these norms, instability of the condyle typically ensues. Anterior disc displacement, especially at the medial pole, past the 11 o’clock position has been shown to create a progressively unstable joint [7] leading to an unstable occlusion and periodontal destruction. Again, it is not possible to visualize these parameters without utilization of MRI imaging and therefore it is imperative that we utilize soft tissue imaging to diagnose and understand the joint condition prior to initiating orthodontic treatment. In summary, before we engage in a complex, interdisciplinary care for our patients, it is imperative that we diagnose the TMJ condition at both the CBCT and MRI level to ensure the stability of our orthodontic and occlusal result.

b

c

Fig. 1  Three parameters of condylar stability visualized on CBCT imaging. (a) Condyle to fossa ratio; (b) absolute condylar dimension; (c) smoothness and convexity of condylar head. (Cited from Piper, DMD MD, Mark. “Temporomandibular Joint Imaging.” Handbook of

Research on Clinical Applications of Computerized Occlusal Analysis in Dental Medicine, edited by Robert B. Kerstein, DMD, IGI Global, 2020, pp. 582–697)

a

b Disc

Anterior

Sagittal View

Example of a Normal TMJ MRI

Posterior

Medial

Disc

Lateral

Coronal View

Fig. 2  Example of normal condyle to disc orientation on TMJ MRI. (a) Sagittal view showing 1 o’clock disc orientation. (b) Coronal view showing mediolateral positioning of disc

Pre-surgical Orthodontic Therapy

Airway Foundation Diagnosis Our understanding of how and the way we breath impacts facial growth and development is not a new concept. For decades, the correlations between modality of breathing, especially oral breathing (“mouth breathing”), and malocclusion have been described [2]. Obstructive airway issues, such as Obstructive Sleep Apnea (OSA) and Upper Airway Resistance Syndrome (UARS), have been tied to narrow maxillary and mandibular development [8] often creating subsequent dental crowding and alveolar insufficiency (Fig.  3). Additionally, both nasal and pharyngeal airway issues have been strongly correlated with parafunctional habits such as grinding and clenching of the jaws [9] which can have a destructive impact on the dentition and periodontium over time. Furthermore, persistence of airway issues after orthodontic treatment has also been attributed to orthodontic relapse, especially of the transverse dimension, crowding, and spacing. As orthodontists, we see the signs of airway issues every day with narrow arches and crowding in our patient population. The recent American Association of Orthodontics (AAO) white paper has stated that proper screening of airway issues is imperative [10] and referral for full diagnosis is key for helping facilitate treatment for our patients with airway issues. Through screening and diagnosis or airway issues, not only can we aid our patients in establishing better health, but we can better understand the underlying cause of our patient’s malocclusion and design our treatment plans to address the airway issues with the benefit of improving the stability of our results. To assess our patient’s airway foundation, we must look at both the nasal and pharyngeal airways. In a dental setting, a comprehensive health history and screening are necessary starting points. The Berlin Questionnaire, Epworth Sleep Scale, and STOP-BANG questionnaires can be easily taken in a dental setting [11–13] In addition, visualization of the

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airways with CBCT imaging may aid in screening of airway issues, particularly of the nasal cavity and pharyngeal airway. It should be noted that CBCT imaging is not diagnostic for obstructive sleep apnea as the dimensions of the pharyngeal airway are fluctuant [14], however, a subnormal pharyngeal airway dimension on a CBCT image can indicate predisposition for sleep disordered breathing based on airway size when compared to the STOP-BANG questionnaire scores [15] so a small pharyngeal airway dimension on a CBCT should not be ignored (Fig.  4). In addition, home sleep testing can be administered by dental professionals as a useful screening tool to assess oxygen and heart rate during sleep as well as efficacy of treatment with appliances. After gathering information in a dental setting, if enough indications for upper airway pathology or potential sleep apnea are found, referral to the necessary medical provider(s) is essential for care. If nasal obstructions such as significant deviations of the septum or enlarged turbinates are encountered, or soft tissue enlargements of tonsils, adenoids, or other obstructions are present on imaging, referral to an Ear, Nose, and Throat (ENT) would be warranted for assessment and treatment. If patients exert symptoms of obstructive sleep apnea, referral to a sleep physician for Polysomnography (PSG) is the gold standard. Recently, new alternatives to PSG have been utilized such as DrugInduced Sleep Endoscopy (DISE) to not only recognize patterns of airway collapse, especially retropalatal, retrolingual, hypopharyngeal, and lateral pharyngeal collapse during sleep. The bottom line is that we, as orthodontists, see the signs of airway issues in our everyday patients. Our patients’ airway issues have often contributed to why they are in our orthodontic chair and may likely increase the likelihood of relapse of our orthodontic result if we do not address the problem. We should take our role seriously in screening patients for airway issues as we and can not only help our

Fig. 3  Example of a 7-year-old patient with enlarged nasal turbinates, Upper Airway Resistance Syndrome, and signs of severe maxillary and mandibular narrow formation, dental crowding, and dentoalveolar insufficiency

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b

Fig. 4  Examples of a patients diagnosed with obstructive sleep apnea (OSA) with narrow pharyngeal airway measured on CBCT. (a) 45-year-old adult patient diagnosed with severe OSA. (b) 6-year-old pediatric patient diagnosed with OSA

treatment last, but also to make a difference in the health of our patients’ lives.

Oral Muscle Foundational Diagnosis The impact of improper oral muscle balance and function on the development of malocclusion is also not a new topic. The presence of ankyloglossia, or tongue restriction, particularly has been found to influence class III skeletal growth [16] narrow arch dimensions and dental crowding [17]. Other muscle restrictions such as high frenum attachments have been shown to contribute to dental spacing [18] as well as recession of the periodontium on the lingual and facial surfaces of lower incisors. Additionally, improper function of oral and facial musculature such as tongue ties, low tongue position, and lip incompetency has also been tied to malocclusion as well as relapse or orthodontic treatment [19]. Therefore, it is pertinent that we, as orthodontists, evaluate our patients’ tongue and oral tissue restrictions as well as oral musculature function prior to beginning orthodontic treatment so that we understand the role these have played in the development of the malocclusion as well as the potential for relapse and possibly the progression of periodontal issues. To evaluate oral and facial musculature and tissue restrictions, thorough examination is necessary. In orthodontic patients, we frequently encounter open mouth posture, poor facial muscle tone, and mentalis strain when looking at our facial photos. When evaluating tongue restrictions, assess-

ment of tongue range of motion is a necessary measurement. Screening tools such as the Tongue Range of Motion Ratio (TMTR) can be looked at to assess tongue range of motion at the tongue tip to incisal papilla (TIP) as well as the lingual palatal suction (LPS) (Fig. 5) [20]. Using these criteria, we can adequately assess if a restriction is significant and requires either therapy or possibly a surgical intervention is necessary. If concerns with facial and musculature are noted, it is indicated to consult with a trained Oral Myologist (OM), or “myofunctional therapist,” for evaluation and therapy and to determine if surgical intervention is necessary. If indicated, therapy to correct improper tongue facial muscle activity can now only allow for correction of proper function, but aid in the stability of our orthodontic results.

Alveolar Bone Foundational Diagnosis When planning orthodontic cases that may require surgically facilitated orthodontic therapy, it is crucial to not only know the type of tooth movements you are striving to achieve, but to also analyze the alveolar bone phenotypes through which you are moving the teeth. Analysis of the alveolar bone thickness cannot be accurately achieved with traditional 2-dimensional orthodontic radiographs, and therefore, advanced imaging with cone-beam CT is a necessary diagnostic tooth to evaluate and diagnose both the crestal and radicular dentoalveolar bone phenotypes. Understanding the thickness of the bone as well as the types of movements is

Pre-surgical Orthodontic Therapy

TRMR-TIP

Grade 1: TRMR-TIP > 80% Significantly Above Average

Grade 3: TRMR-TIP < 50% Below Average

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Assessment at:

Anterior Tongue Mobility Tongue to Incisive Papilla (TIP)

Grade 2: TRMR-TIP 50–80% Average

Grade 4: TRMR-TIP < 25% Significantly Below Average

TRMR-LPS

Grade 1: TRMR-LPS > 60% Significantly Above Average

Grade 3: TRMR-LPS < 30% Below Average

Assessment at:

Posterior Tongue Mobility Lingual Palatal Suction (LPS)

Grade 2: TRMR-LPS 30–60% Average

Grade 4: TRMR-LPS < 5% or unable Significantly Below Average

Fig. 5  Functional classification of ankyloglossia based on tongue range of motion ratio (TMTR). (Cited from Zaghi, S., Shamtoob, S., Peterson, C., Christianson, L., Valcu-Pinkerton, S., Peeran, Z., Fung, B., Kwok-Keung Ng, D., Jagomagi, T., Archambault, N., O'Connor, B.,

Winslow, K., Lano, M., Murdock, J., Morrissey, L., & Yoon, A. (2021). Assessment of posterior tongue mobility using lingual-palatal suction: Progress towards a functional definition of ankyloglossia.  Journal of oral rehabilitation, 48(6), 692–700)

imperative for predictable and safe tooth movement. Utilization of treatment simulation software, such as SureSmile®, can also be very useful as it allows us to visualize the alveolar bone thickness and root interface. With SureSmile®, tooth movement simulations have been shown to be predictable [21] and allow us to visualize the pre-­ treatment and post-treatment root-alveolar bone interface that result from such tooth movement and predict the safety of tooth movement (Fig.  6). Most importantly, tooth ­movement simulations are also a helpful communication tool to our patients and interdisciplinary team about why surgically facilitated orthodontic therapies are necessary and where they should be performed. Using the Mandelaris classification system of dentoalveolar bone phenotypes [22], CBCT imaging is utilized to diagnose alveolar bone thickness in the crestal zone (measured from the CEJ to 4 mm apical to the CEJ) and radicular zone (measured from the base of crestal zone to the apex of root) (Fig. 7). Alveolar bone is considered “Thick” if the width is measured greater than 1 mm, and “Thin” if the width is less than 1 mm in the respected areas of interest. Subsequently, there are four possible classifications of dentoalveolar bone that can be diagnosed from the Mandelaris classification: “Thick/Thick” where there is thick crestal and thick radicu-

lar bone; “Thick/thin” where there is thick crestal bone, but thin radicular bone; “Thin/Thick” where there is thin crestal bone and thick radicular bone; and “Thin/Thin” where there is both thin crestal and radicular alveolar bone phenotypes (Fig. 8). The diagnosis of alveolar phenotypes must be completed for both the labial/buccal and lingual/palatal tooth surfaces to understand the bone quality and risk for orthodontic tooth movements [23]. Diagnosing our patient’s dentoalveolar bone phenotypes prior to beginning orthodontic treatment is paramount as it allows us to understand where there are potential issues with the alveolar foundation that would make certain tooth movements risky. Understanding our patient’s alveolar bone structure also allows us to design interdisciplinary treatment to utilize surgical facilitated orthodontic therapies such as bone and soft tissue augmentation to create adequate alveolus to allow for our desired tooth movements and esthetic outcome. When treatment planning orthodontic treatment and considering surgically facilitated orthodontic therapy, it is also necessary to analyze the dentoalveolar bone phenotypes in different areas of the mouth. For example, the maxillary posterior and mandibular posterior teeth have different types of movements in the maxillary anterior region. Therefore, it is necessary to look at each of these areas individually and

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a

b

Fig. 6  Example of SureSmile pre- and posttreatment simulation alveolar bone and root interface. (a) Pretreatment with thin labial bone on central incisors. (b) Posttreatment after alignment of teeth with loss of alveolar bone

phenotype categories and possible anatomical combinations presented as a Punnett square

Radicular zone, B

THICK-THICK

THIN-THICK

Phenotype Crestal zone, 4mm

Thick Radicular zone,

Crestal zone, 4mm

Phenotype

Thin

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Crestal Zone

X

Crestal Zone

Radicular Zone

X

Radicular Zone

THIN-THIN

Fig. 7  Example of upper incisor showing labial and palatal crestal and radicular zones of alveolar bone

assess them in conjunction to the desired tooth movements to determine if bone or soft tissue augmentation is necessary as part of treatment. The following are specific considerations for each region in regard to their dental alveolar phenotypes and tooth movement desired:

 axillary Anterior Region M In the maxillary anterior region, the need to set the incisors in the proper position inciso-gingivally and at the correct labio-

X

X THICK-THIN Phenotype

Phenotype Thick

Thin

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Thick

Crestal Zone

X

Crestal Zone

Radicular Zone

X

Radicular Zone

Thin

X

X

Crestal zone = CEJ → 4 mm apical; Radicular zone = base of crestal zone → apex; thick phenotype = ≥ 1 mm of facial bone; thin phenotype =1mm

SFOT Not indicated

SFOT indicated

SFOT Not indicated

Not indicated

SFOT indicated

SFOT indicated

SFOT indicated

•

Tooth movement will produce Palatal Root torque/Labial Crown torque

SFOT Not indicated

SFOT if root movement >1mm

SFOT Not indicated

SFOT indicated

SFOT indicated

SFOT Not indicated

SFOT indicated

SFOT indicated

•

Need for advancement of the dentition bodily >1mm

SFOT indicated

Not indicated

SFOT indicated

SFOT likely not indicated

SFOT indicated

Possible SFOT indication

SFOT indicated

SFOT indicated

•

Desire for increased rate of tooth movement

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

Fig 10  SFOT decision flow chart for maxillary anterior dentition based on alveolar phenotypes

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some retraction or tipping of the clinical crown may be desired to achieve a more upright incisor appearance. Another example would be a class II, division 2 patient with retroclined incisors where any further retraction would be a high-risk movement. In both examples, corticotomies and osseous grafting in c­ombination with orthodontics would help safely facilitate these movements as well as speed the rate of tooth movement. Maxillary Anterior Thin/Thick Phenotypes Patients with this anterior phenotype may have clinical recession already as the bone is thin in the crestal region. Tipping movements labially or lingually may cause more crestal bone loss and make for more anterior recession. Soft and hard tissue grafting in combination with orthodontics may be indicated to help with the tooth movement and maintain root coverage in the crestal area. Maxillary Anterior Thin/Thin Phenotypes With this phenotype, the alveolar bone will have very little tolerance for tooth movement and the patient will be at high risk of significant bone loss during orthodontics. Soft and hard tissue grafting both labially and palatally should be considered if this phenotype is encountered.

 andibular Anterior region M In the mandibular anterior region, we commonly encounter thin alveolar phenotypes [24]. Lower anterior crowding is a common chief complaint of orthodontic patients and so it is very important that we understand the quality of alveolar bone in the area and potential consequences for alignment of teeth before we start treatment (Fig. 11). Class II malocclusions are another common finding in orthodontic patients and correction is often mostly achieved with dentoalveolar Labial Bone Alveolar Phenotypes THICK/THICK

THIN/THICK

THICK/THIN

THIN/THIN

Fig. 11  Examples of mandibular labial and lingual alveolar phenotypes

movement [25]. Treatment mechanics for class II correction, such as elastics or functional appliances, place mesial forces on the lower anterior teeth that may strain the alveolar bone and cause recession, especially if the forces are heavy or prolonged to correct a large class II discrepancy. Patients with class III malocclusion also present with unique alveolar bone considerations as retraction of the lower anterior clinical crowns is often pursued in camouflage treatment to achieve proper overjet and anterior articulation. Class III dental corrections often involve elastics, class III correctors, and interproximal reduction (IPR) that all place lingual forces on the clinical crown and labial root forces. Therefore, it is necessary to know the alveolar bone quality before deciding on class III correction mechanics and if the bone or soft tissues need augmentation. Finally, patients with anterior open bite malocclusions often have unique alveolar bone considerations. Thin alveolar bone is often noted in the lower anterior region with this malocclusion and very often teeth may be excessively proclined due to a tongue functional issue. Non-­surgical, correction of anterior open bites often involves extrusive and retractive forces which can strain the alveolus, therefore we need to understand the quality of alveolar bone before deciding on the mode of correction and if surgically facilitated therapies are necessary (Fig. 12). Mandibular Anterior Thick/Thick Phenotype In this phenotype, labiolingual tooth movements are generally well tolerated within a normal range of motion that would keep the roots within the 1  mm thick bone in the crestal and radicular regions. If more aggressive movements are desired, such as advancing mandibular anterior teeth greater than the 1 mm cortical bone to correct a class II malocclusion, then soft and hard tissue grafting would be indiLingual Bone Alveolar Phenotypes THICK/THICK

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Desire for increased rate of tooth movement

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

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Fig 12  SFOT decision flow chart for mandibular anterior dentition based on alveolar phenotypes

cated to aid in bodily advancement of the mandibular anterior teeth. Additionally, if accelerated tooth movement is desired with this phenotype, interradicular corticotomies would be beneficial in enhancing the rate of tooth movement. Mandibular Anterior Thick/Thin Phenotypes With this phenotype, understanding what our orthodontic movements are doing in the radicular region is very important. Although tipping movements will be generally well tolerated in the crestal zone, the thin radicular phenotype will make root torque important to understand. If there is thin radicular bone on the labial side, retractive crown movements such as class III mechanics can potentially cause labial root torque that may compromise a thin cortical plate. Also, excessive labial root torque bracket prescriptions that are commonly used in class II correction mechanics to counter excessive crown tipping may lead to the roots straining the thin radicular bone. In these cases, hard tissue augmentation will be indicated to allow for proper bone in the area to safely accomplish these movements. If there is thin lingual radicular bone, excessive proclination of the lower incisors, possibly from heavy or prolonged class II mechanics, may cause the root apex to strain the lingual thin bone. In a case of this type, it may be more ideal to have labial corticotomies and hard tissue augmentation to allow the lower anterior teeth to advance bodily rather than excessively tip the dentition. Mandibular Anterior Thin/Thick Phenotypes Patients with this anterior phenotype often have previous  clinical recession or a thin gingival phenotype as the bone is thin in the crestal region. Unraveling excessive crowding in the lower anterior region may lend itself to significant bone loss and recession, therefore, hard and soft tissue augmentation is likely needed to facilitate safe movement. Tipping movements labially or lingually, for example, to correct a mild class II or III with elastics, are also risky in this phenotype may cause more crestal bone loss and cause anterior recession. Corticotomies and soft and hard tissue grafting in combination with orthodontics may be indicated to

help with the tooth movement and maintain root coverage in the crestal area. Mandibular Anterior Thin/Thin Phenotypes Similar to the maxillary anterior region, with this phenotype, the alveolar bone will have very little tolerance for tooth movement and the patient will be at high risk of significant bone loss during orthodontics. Soft and hard tissue grafting both labially and lingually should be considered when this phenotype is encountered.

 he Maxillary Posterior Region T Analysis of the alveolar bone in the maxillary posterior region is especially important when considering skeletal or dental expansive orthodontic therapy. As orthodontists, we often desire to expand the maxillary arch to achieve numerous goals (correction of dento-skeletal crossbites, increasing oral cavity volume, nasal airway improvement, increasing buccal corridor width, etc.) and it can be tempting to plan treatment with these goals in mind but without consideration for the alveolar foundation. In our nongrowing patients especially, there has traditionally been concern about dental tipping or torque pushing the teeth out of the alveolus when attempting dental, non-surgical, or non-skeletally based expansion. Recently, new techniques to expand the maxilla with bone-based skeletal expanders, micro-implant assisted rapid palatal expansion (MSE, MARPE), and distraction osteogenesis maxillary expansion (DOME) have changed our thinking of how to expand the maxilla at the skeletal level in adults and have been shown to improve nasal breathing [26] and oral cavity volume in ways that limit  stress to  the dentoalveolar complex during expansion [27]. Nevertheless, regardless of the style of orthodontics we are pursuing, we need to diagnose the pre-treatment alveolar bone phenotypes to be able to anticipate what the tooth movements needed to finish our occlusion will do within the alveolus, and plan if surgical facilitated therapies are needed to accomplish them (Figs. 13 and 14).

D. McDonald

170 Buccal Bone Alveolar Phenotypes THICK/THICK

THICK/THIN

THIN/THICK

THIN/THIN

Palatal Bone Alveolar Phenotypes THICK/THICK

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Fig. 13  Maxillary posterior phenotypes buccal and palatal Thick/Thick Alveolar Phenotype •

•

•

CBCT Findings

Buccal

Palatal

Buccal

Palatal

Buccal

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alveolus

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alveolus

alveolus

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Maxillary Skeletal Expansion planned

indicated SFOT possible if root movement >1mmc SFOT Not indicated

•

•

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Desire for increased rate of tooth movement

Thin/Thin Alveolar Phenotype

alveolus

SFOT possible if root movement >1mm

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Tooth movement will produce Buccal Root torque/Palatal Crown torque

•

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SFOT possible if root movement >1mmc SFOT indicated

indicated

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SFOT Not indicated

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indicated

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SFOT possible if root movement >1mmcv

SFOT possible if root movement >1mmc

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indicated

SFOT indicated

SFOT indicated

SFOT possible if root movement >1mmc

SFOT Not

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

Fig. 14  SFOT decision flow chart for maxillary posterior dentition based on alveolar phenotypes

Maxillary Posterior Thick/Thick Phenotype In this phenotype, buccolingual tooth movements are generally well tolerated within a normal range of motion that would keep the roots within the current >1 mm thick bone in the crestal and radicular regions. If more aggressive movements are desired, such as dental expansion greater than the 1 mm cortical bone, soft and hard tissue grafting would be indicated to aid in bodily advancement of the maxillary posterior teeth. Additionally, if accelerated tooth movement is desired with this phenotype, interradicular corticotomies would be beneficial in enhancing the rate of tooth movement. Maxillary Posterior Thick/Thin Phenotypes With this phenotype, similar to the anterior region, it is imperative to know how your tooth movement will express in the apical area of the root. If there is thin radicular bone on the buccal surface, tooth movements that torque the root labially will be high risk as the root may push into or through the cortical plate. A common example of this would be a nar-

row maxilla where the posterior teeth have excessive curve of Wilson with the crown tipped buccally (commonly with a low hanging palatal cusp) and roots tipped palatally. If the desired tooth movement is to center the crown on the long axis of the root within the bone, buccal root torque will be expressed which may stress the thin radicular alveolus. Another common example would be if a posterior dental crossbite existed where the crown is excessively palatally inclined with the root being buccally tipped. To correct the tooth position, either for crossbite correction, or centering the tooth on the long axis, the root may tip palatally and stress the thin alveolus. In both examples, even with a maxillary skeletal expansion technique, corticotomies and osseous grafting would help safely facilitate the tooth movements needed as well as speed the rate of tooth movement. Maxillary Posterior Thin/Thick Phenotypes Patients with this posterior phenotype may have previous clinical recession as the bone is thin in the crestal region. Tipping movements labially or palatally may cause more

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crestal bone loss and make for more recession. This would be a strong indication to pursue maxillary skeletal expansion (surgical or non-surgical) to prevent tipping of the dentition and preservation of the thin bone, instead of dental-only expansion. Even with maxillary skeletal expansion though, it may be necessary to pursue soft and hard tissue grafting in combination with orthodontics  to help facilitate  the tooth movement and maintain or re-gain root coverage in the crestal area. Maxillary Posterior Thin/Thin Phenotypes With this phenotype, the alveolar bone will have very little tolerance for tooth movement, and the patient will be at high risk of significant bone loss during orthodontics. If expansion is desired, maxillary skeletal expansion should be pursued (either surgically or non-surgically) but corticotomies, soft and hard tissue grafting, both labially and possibly palatally should be considered as the finishing of the occlusion will still necessitate tooth movement through thin alveolar bone and create a high risk for clinical attachment loss.

 he Mandibular Posterior Region T The mandibular posterior region is unique in that tooth malposition often is an adaptation to the maxillary tooth position. As an example, in most cases of narrow maxillary development, we often see an excessive curve of Wilson to the mandibular arch where the crowns are lingually inclined. Subsequently, when we plan our maxillary tooth and skeletal movements, especially expansion, we also need to plan for the mandibular tooth movements to allow proper interdigitation and occlu-

sion. As mentioned previously, the advent of new maxillary skeletal expansion techniques, especially for airway improvement, has made this an attractive option for orthodontic therapy. When planning for this type of treatment, it is imperative to assess the alveolar bone of the posterior mandible (Fig. 15) to decide if the amount of maxillary expansion desired can be accompanied by dental uprighting and expansion of the mandibular teeth within the current alveolar structure. If concerns are present regarding the alveolar bone phenotypes, or if we desire even to go beyond the existing alveolar dimensions and add bone to maximize the expansion of the maxilla we would need to plan to add buccal bone through hard tissue augmentation to allow the desired tooth movements (Fig. 16). In short, when an airway directed treatment plan is being considered, surgically facilitated orthodontic treatment can dramatically increase the range of possibilities and amount of maxillary expansion that can be accomplished. Mandibular Posterior Thick/Thick Phenotype In this phenotype, buccolingual tooth movements are generally well tolerated within a normal range of motion that would keep the roots within the current >1  mm thick bone in the crestal and radicular regions. If more aggressive movements are desired, such as dental expansion such greater than the 1 mm cortical bone to allow for more maxillary skeletal expansion, then soft and hard tissue grafting would be indicated to aid in bodily expansion of the mandibular posterior teeth. If accelerated tooth movement is desired in this phenotype, with or without expansion, interradicular corticotomies would also be beneficial in enhancing the rate of tooth movement.

Buccal Bone Alveolar Phenotypes

Lingual Bone Alveolar Phenotypes

THICK/THICK

THICK/THIN

THICK/THICK

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THIN/THICK

THIN/THIN

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Fig. 15  Examples of mandibular posterior buccal and lingual alveolar phenotypes

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D. McDonald Thick/Thick Alveolar Phenotype

Thick/Thin Alveolar Phenotype

•

CBCT Findings

•

Tooth movement will produce Buccal Root torque/Lingual Crown torque

SFOT possible if root movement >1mm

SFOT Not indicated

SFOT indicated

•

Tooth movement will produce Lingual Root torque/Labial Crown torque

SFOT Not indicated

SFOT possible if root movement >1mm

SFOT Not indicated

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Need for expansion the dentition bodily

SFOT possible if root movement >1mmc

SFOT Not indicated

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Maxillary Skeletal Expansion planned

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Desire for increased rate of tooth movement

Buccal alveolus

SFOT Not indicated

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SFOT indicated

SFOT indicated

SFOT indicated

SFOT Not indicated

SFOT indicated

SFOT indicated

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SFOT Not indicated

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SFOT indicated

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SFOT Not indicated

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SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

SFOT indicated

Buccal alveolus

Lingual alveolus

Thin/Thin

SFOT indicated

Buccal alveolus

Lingual alveolus

Fig 16  SFOT decision flow chart for mandibular posterior dentition based on alveolar phenotypes

Mandibular Posterior Thick/Thin Phenotypes It is imperative to know how your tooth movement will express in the apical area of the root with this phenotype. If there is thin radicular bone on the buccal surface, tooth movements that torque the root buccally will be high risk as the root may move into or through the cortical plate. A common example of this would be a patient with tight buccal occlusion where camouflage treatment would be pursued to constrict the mandibular arch to obtain buccal overjet. This movement would produce lingual crown movement and possibly buccal root torque which could stress the thin alveolar bone especially in the premolar region where the radicular bone is often not as thick as the molar region. This would be an indication for corticotomies and osseous grafting to safely facilitate as well as speed the rate of this tooth movement. Maxillary Posterior Thin/Thick Phenotypes Patients with this posterior phenotype often have clinical recession, especially in non-growing patients if there has been significant longstanding curve of Wilson and a lack of proper anterior guidance. It is not uncommon for these patients to have abfractions present as the bone is thin in the crestal region. Tipping movements labially or palatally may cause more crestal bone loss and make for more recession. In a case where expansion of the maxilla is indicated, either skeletally or dentally, and thin buccal crestal bone is present, uprighting of the lower arch to maintain proper interdigitation with the maxillary teeth would stress the bone and likely lead to clinical attachment loss. This would be a strong indication for buccal corticotomies, soft and hard tissue augmentation to help safely facilitate these movements. In a case where there is thin crestal bone on the lingual side, it may not be advisable to restrict the lower arch to camouflage a tight buccal occlusion as it may lead to lingual surface recession.

Mandibular Posterior Thin/Thin Phenotypes With this phenotype, the alveolar bone will have very little tolerance for tooth movement and the patient will be at high risk of significant bone loss during orthodontics. Corticotomies, soft and hard tissue grafting, both labially and possibly lingually should be considered with any orthodontic tooth movement as this patient is at a high risk for clinical attachment loss.

 rthodontic Diagnosis: Facial and Smile O Esthetics After diagnosing the foundational issues of our patient’s TMJ, airway, muscular, and alveolar bone, we can proceed to designing our esthetic result so that we know where to move the teeth and how to do it safely. More importantly, if there are foundational issues to moving the teeth to their desired position, we will know if interdisciplinary care will be needed to facilitate our esthetic smile goals.

I deal Position of Maxillary Anterior Teeth When we begin our treatment planning process for each orthodontic case, it is helpful to start with the end in mind. At the esthetic level, this starts with setting our desired end point of our maxillary dentition for proper positioning, display, smile arc, smile width, and lip support within patient’s facial and skeletal structure. Therefore, in planning our orthodontic outcome, we need to consider where to best position the dentition, starting with the central incisor, in all three planes of space. In the coronal plane, the maxillary central midline position, angulation, smile arc, and smile width have all been found to be very influential in the esthetic display of the smile. Ideally, the midline of the maxillary central should be

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positioned at the center of the facial midline with deviations between 2 mm [28] and 4 mm [29] being found as acceptable to laypersons. The midline angulation also needs to be considered as only a 2 mm deviation of the central incisor midline angulation was found to be unesthetic [29]. The arc of the smile has been found most pleasing when it follows the lower lip line [30]. In the transverse dimension, previous studies have shown that central incisor and gingival display at rest and during full smile are very influential in smile esthetics. During reposed smiles, it has been found most pleasing to have maxillary incisor display at rest slightly less for males ~2  mm than for females ~3.5 mm [31]. At full smile, 100% cervico-­ incisal display of the maxillary central incisors with the upper lip line resting at or just above the gingival margin was found most pleasing [32]. Conversely, an excessive amount of gingival display during smile has been examined and found to be undesirable but small amounts of gingival show are acceptable [33]. When designing our patient’s esthetic treatment plan, it is very helpful to utilize treatment simulation software to visualize the tooth movements needed to bring the incisors into the proper smile arc and if those movements will stress the alveolar bone housing present before treatment. If so, it may be imperative that surgical augmentation of the bone be done in concert with orthodontic tooth movement to facilitate safe and stable movement of the teeth (Fig. 17). Finally, the maxillary incisor labiolingual inclination in the sagittal plane is perhaps the most widely debated topic of smile and profile esthetics. From a lateral profile perspective, it is generally agreed upon that the maxillary incisor position should fall between the reference lines of the forehead anterior limit line (FALL) and a vertical line through the glabella anterior limit line (GALL) in a lateral photograph [34] (Fig.  18). At the tooth level, the labiolingual angulation of the central incisors is the most important plane of analysis when considering surgical facilitation to achieving an ideal result as the root torquing movements needed to accomplish the desired tooth angulation need to be  executed safely within the dimension of the alveolar bone. For the maxillary central incisors, the labiolingual angulation has a significant effect on the perceived smiling profile esthetics. It has been a

b

found that a central incisor angulation that is slightly upright or lingually inclined is esthetically more pleasing than incisors with excessive labial inclination [35]. If, for example, a patient presents initially with excessive labial crown inclination of their central incisors, the root movement that would need to take place to upright them would necessitate labial

Fig. 18  Example of ideal facial incisor labio-lingual position between the facial anterior limit line (FALL) and glabella anterior limit line (GALL). Cited from Resnick, C. M., Kim, S., Yorlets, R. R., Calabrese, C. E., Peacock, Z. S., & Kaban, L. B. (2018). Evaluation of Andrews' Analysis as a Predictor of Ideal Sagittal Maxillary Positioning in Orthognathic Surgery. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons, 76(10), 2169–2176

c

Fig. 17  Example of SureSmile simulation software set up showing teeth alignment within smile arc. (a) Pre-treatment patient photo showing smile display. (b) Pre-treatment, before tooth alignment into smile arc. (c) Post-treatment, after simulated alignment of teeth into smile arc

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root torque. When considering increasing the labial root torque in a skeletally mature patient, it is important to understand the bone phenotype around that root, especially in the radicular area, as the root will need sufficient bone to safely achieve this movement. If the phenotype of the patient’s bone is thin in the radicular zone, the patient would most benefit from surgical facilitation of orthodontics through bone augmentation to safely achieve this final incisor positioning in the labiolingual inclination zone.

D. McDonald

130º

Orthodontic Diagnosis: Functional Occlusion After determination of the ideal coronal, transverse, and labiolingual inclination of our maxillary central incisors, the positioning of the remaining dentition can now be set for proper esthetics and function. In our planning to establish a proper functional occlusion that supports the maxillary anterior dentition, it is of upmost importance that we consider the foundational structures of the TMJ, airway, and especially the alveolar bone phenotypes, to ensure that the tooth movements needed can be achieved safely and without compromising the foundation so that they will be stable over time.

I deal Position of Upper Incisors Dictates Lower Incisors The positioning and angulation of the lower incisors are most notably dictated by the maxillary incisor positioning as the two must articulate for proper function. In an ideal occlusion, the lower incisors articulate with the marginal ridges of the maxillary incisors with a range between 5 and 40% vertical overbite as acceptable norms. In the sagittal dimension, the angulation and position of the upper and lower incisors in relation to one another are also very important. The Ricketts analysis (Fig. 19) describes an ideal interincisal angle between the lower and upper incisors as 130° [36].  anagement of Anterior-Posterior (A-P) M Problems in the Skeletally Mature Patient Using SFOT After analyzing the anterior-posterior position of the maxilla, mandible, and the incisors, it is important to understand how best to correct discrepancies from the norm to achieve proper esthetics and function while not stressing the alveolar bone phenotype beyond its limits. In skeletally mature patients, our options of growth are limited to correct A-P skeletal discrepancies and so we often must pursue surgical intervention in the form of orthognathic surgery, SFOT, or a combination of both to achieve optimal results. In cases with obvious severe skeletal deformities of the maxilla and mandible or when significant airway issues are present, large skeletal movements via orthognathic surgery

Fig. 19  Example of maxillary and mandibular incisor ideal interincisal angulation as described by Robert Ricketts. (Cited from Meneghini F., Biondi P. (2012) Dentofacial Deformities. In: Clinical Facial Analysis. Springer, Berlin, Heidelberg)

would be indicated to achieve the most beneficial effect. In mild to moderate skeletal class II or class III cases, the correction of anterior-posterior discrepancies can be significantly improved with surgically facilitated orthodontic tooth movements. For example, in a mild class III patient, bodily advancement of the maxillary anterior dentition could be facilitated by the addition of osseous grafting to the labial surface of the maxillary anterior teeth (Fig.  20). Another example would include treatment of a mild to moderate class II skeletal patient where the labial bone is thin. In this case, labial tissue and bone augmentation would allow for bodily advancement of the mandibular incisors to reduce overjet without pushing the incisors through the thin cortical plate (Fig. 21). In all cases where A-P issues are encountered in skeletally mature patients, it is imperative that the alveolar bone phenotypes are assessed to determine if SFOT would be a useful adjunct therapy to resolve the discrepancy.

Transverse Analysis The transverse dimension of the maxilla and mandible is often insufficient in both our adolescent and adult orthodontic patients. At the esthetic level, transverse discrepancies often present themselves as smile width deficiencies where the patient may have narrow buccal corridors that are often a detriment to the overall smile esthetics. Previous research has shown that smiles that have first molar-to-first molar show resulting small buccal corridors have been found to be more attractive by orthodontists [37]. We must

Pre-surgical Orthodontic Therapy

a

175

b

c

Fig. 20 (a) Example of mild skeletal class III patient on cephalometric analysis. (b) Pre-orthodontic evaluation shows thin alveolar phenotypes. (c) Simulated treatment for advancement of maxillary anterior

a

b

dentition bodily to increase overjet would necessitate labial bone augmentation with SFOT

c

Fig. 21 (a) Example of moderate skeletal class II on cephalometric analysis. (b) Thin bone is present pre-orthodontic treatment. (c) Patient simulation shows advancement of mandibular anterior dentition bodily to correct overjet would necessitate labial bone augmentation with SFOT

look beyond the tooth and smile esthetics, though, when analyzing the transverse dimension of our patients. At the foundational level, we must look under the surface via CBCT, to analyze the width of the maxilla and mandible at the alveolar bone level and assess the angulation of the dentition within the alveolus to truly diagnose transverse issues  especially because  transverse discrepancies of the maxilla and mandible do not always present with a dental crossbite, but instead can present  with excessive curve of Wilson  the disguises the transverse deficiencies. Most importantly, when we analyze the transverse dimension for our patients, is imperative that we determine the etiology to best decide how best to correct it. Transverse dimension deficiencies have been often correlated with upper airway obstructive issues [38], tongue functional issues [17], and recessive mandibular growth. Therefore, it is important that we determine the etiology of the transverse issue before deciding our course of action to correct it.

Transverse Analysis of Maxilla When analyzing the maxillary transverse dimension, traditionally we have looked to intermolar width as the key measurement. Previous literature has pointed to a normal maxillary intermolar width of 36–39  mm for skeletally mature patients, with a measured width below this being considered narrow [39]. We cannot stop at teeth measurements, though, when assessing the transverse dimension. Often the maxillary molars may be tipped buccally with an accentuated Curve of Wilson creating an intermolar width that is near ideal, however the maxillary skeletal width can be narrow under the surface (Fig. 22). Ideally, the maxillary and mandibular dentition should be centered within the alveolus with the long axis of the teeth in harmony [34] (Fig. 23). More recent studies have looked at CBCT imaging to help assess the width of the maxilla and mandible by taking measurements at the center of resistance of the molars to assess the basal arch width [40]. Patients with class I normal occlu-

176

D. McDonald

a

b

Fig. 22 (a) Example of a near normal intermolar width measurement due to tooth tipping with a small nasal base measurement shown on the CBCT (b)

the maxillary alveolus and bone width to assess the true maxillary width as well as the dental width and angulations to determine the degree of maxillary transverse discrepancies. X’ -9º

-9º

-30º

-30º

X

Fig. 23  Example of an ideal intermolar relationship as described by Andrews 6 keys to occlusion. Cited from Resnick, C.  M., Kim, S., Yorlets, R. R., Calabrese, C. E., Peacock, Z. S., & Kaban, L. B. (2018). Evaluation of Andrews' Analysis as a Predictor of Ideal Sagittal Maxillary Positioning in Orthognathic Surgery.  Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons, 76(10), 2169–2176

sion were found to have average maxillary basal arch widths near 48  mm and nearly identical center of resistance measurements between the maxillary and mandibular molars. Center of resistance measurements were found to be smaller on the maxillary dentition than the mandible in patients with maxillary transverse discrepancies [41] (Fig.  24). Also important is that the width of the maxillary dentition at the basal arch width be ~5 mm wider than the mandibular dentition. With the widespread use of CBCT imaging in today’s dental world, it is important that we visualize and measure

Transverse Analysis of Mandible Harmony between the transverse dimensions of the maxillary and of the mandibular arches is needed for ideal occlusal function. The mandibular transverse dimension is often overlooked as much of our attention is on discrepancies of the maxilla and the ability to expand it. Differing from the maxilla, the mandible is one bone that is not easily expanded, and so transverse issues of the mandible must be addressed with dental uprighting when encountered. The most frequent happenstance of mandibular transverse discrepancy comes in the form of excessive Curve of Wilson of the dentition, often an adaptation of the mandibular teeth to meet a narrow maxillary dentition and maintain cusp-fossa interdigitation. In these cases, the maxillomandibular width differential of ~5 mm may be maintained, but the mandibular teeth may be significantly lingually tipped. Therefore, it is not adequate to only assess the transverse dimension of the mandible with only tooth measurements and we must look in 3D with CBCT imaging. As mentioned previously, CBCT studies have looked at the center of resistance of the molars to evaluate the transverse dimension at the alveolar level, noting that normal first molar width for class I individuals was near 48 mm [41] (Fig. 23). Given that the mandibular alveolus is more set in its dimension than the maxilla, as well as the fact that the maxilla and mandible need to be in harmony with each other at the alveolar level for the dentition to align along their long axes, it is imperative that the mandibular transverse dimension be analyzed at the alveolar level so that the plan for the maxilla can be set to match it accordingly with expansion of the maxilla is necessary.

Pre-surgical Orthodontic Therapy

YTI at the first molar

Normal occlusion Difference =−0.39 ± 1.87 mm

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Mx. CR width

Mx. dental width (tip)

Difference = 8.43 ± 2.22 mm

Mn. dental width (tip)

Mn. CR width p < 0.001

NS

Mx. CR width

Class III malocclusion Difference =−3.17 ± 3.17 mm

Mx. dental width (tip)

Difference = 7.81 ± 2.83 mm

Mn. dental width (tip)

Mn. CR width

Fig. 24  Example showing maxillomandibular width at the center or resistance normal occlusion vs class III malocclusion. (Cited from Koo, Y. J., Choi, S. H., Keum, B. T., Yu, H. S., Hwang, C. J., Melsen, B., & Lee, K.  J. (2017). Maxillomandibular arch width differences at esti-

mated centers of resistance: Comparison between normal occlusion and skeletal Class III malocclusion. Korean journal of orthodontics, 47(3), 167–175)

Management of Transverse Problems in the Skeletally Mature Patient Using SFOT The transverse dimension is commonly deficient in our skeletally mature patients. The underlying etiology of transverse deficiency can often be correlated to many factors including upper airway restriction, tongue posture dysfunction, class II skeletal malocclusion, temporomandibular joint dysfunctions, and oral habits [8, 17, 42] For these reasons, it is important to determine the etiology of the patient’s transverse discrepancy, first, in order to determine goals of treatment and how to address the etiology along with the occlusal correction. For example, if the patient presents with a narrow maxilla and narrow nasal base width, the etiology behind malocclusion is likely rooted in upper airway restriction or tongue dysfunction. In this case, the patient may benefit most from maxillary skeletal expansion, surgical or non-surgical, to increase their nasal base size and improve their airway, along with possible myofunctional treatment of their tongue dysfunction and ENT referral as needed (Fig.  25). If the patient presents with a normal maxillary width or nasal base on their CBCT, but is in narrow transverse dental articulation or crossbite, their etiology is likely not rooted in upper air-

way restriction and so their correction would likely not need to involve expansion and would involve tooth movement only in the transverse direction (Fig. 26). The use of CBCT is necessary as a standard of care to determine where the deficiency lies and to drive our treatment decisions. After consideration for etiology of the transverse deficiency in our patients’ treatment goals and plan, we must next look at how the teeth themselves must move within the alveolus to establish proper torque and root position for the stability of our final occlusion. At the same time, we must also look at the alveolar bone itself to determine if the bone phenotype is adequate to handle these root movements. Transverse dimension discrepancy does not always present itself as a true reverse-articulation crossbite but can often be hidden in the form of dental compensations and pronounced lingual inclination of teeth or curve of Wilson. The prescriptions we use in our orthodontic fixed appliances or aligner therapy are programmed to express root torque movements in the buccal or lingual planes as the clinical crowns of the teeth are aligned. For this reason, we must analyze the alveolar bone housing surrounding the roots of the teeth we wish to move prior to

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Fig. 25  Example of skeletally-mature patient with narrow maxillary arch dimension and nasal obstruction. (a) The patient has excessive maxillary and mandibular curve of Wilson; (b) The maxillary arch

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width at the first molar measures 31  mm. (c) The nasal cavity is obstructed with enlarged turbinates and a mild deviated septum and the skeletal measurement of the nasal base is narrow

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Fig. 26 (a) Example of skeletally-mature patient with bilateral maxillary crossbite correction using SFOT. This patient underwent bilateral maxillary posterior osseous grafting with expansive tooth movement to

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resolve his crossbite along with pre-prosthetic alignment of the gingival margins (b) and tooth form was then temporized with flowable composite prior to orthodontic finishing (c)

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Fig. 27 (a) Example of unilateral maxillary crossbite with thin/thin labial alveolar phenotype before treatment (a, b) and resulting new thick labial bone after osseous grafting and expansion to correct crossbite (c, d)

beginning orthodontic treatment, especially in our patients lacking transverse skeletal dimension, in order to know if we will safely be able to achieve expansive tooth movement and proper root torque without causing dehiscence or fenestration of the alveolar bone over the roots. Using CBCT imaging, we are able to analyze the bone phenotype surrounding the roots prior to treatment. Adjunctively, we can utilize treatment simulation technology that incorporates the patient’s CBCT imaging to determine if the root movements necessary to establish our desired occlusal goals can be safely achieved with the patient’s pre-treatment bone phenotypes. If the bone phenotype is thin and the roots require buccal torque throughout their movement, surgical facilitation of orthodontics would be necessary

via bone and soft tissue augmentation to achieve this movement safely (Fig. 27).

 FOT and the Impact on Expanding Oral S Cavity Volume and Airway Dimensions: The Intersection of Dentistry and Health Our role as dentists is changing within the world of medicine. For decades, the link between the oral cavity and systemic health has been recognized and our understanding continues to evolve regarding how much we, as dentists, can help with our patient’s overall health. One of the most researched connections of dentistry and medicine has been interactive rela-

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tionship of the oral cavity and airway issues. In orthodontics, we have a unique perspective on airway issues as many patients entering our office for treatment have significant malocclusions, often with underlying airway conditions that have contributed to their formation. Previous research has shown that breathing disorders contribute to narrow arch development and recessive jaw growth often creating alveolar insufficiency and dental crowding [43, 44]. Furthermore, smaller jaws, narrow dental arches, and the subsequent smaller oral cavity volume have been correlated with smaller nasal cavity volume [45], subnormal pharyngeal airway dimension, and an increased risk for sleep disordered breathing [46]. What we also know is, as orthodontist, we have the unique skillset to design and execute treatment to address dental and skeletal structural issues via dental and orthopedic expansion and surgical interventions. It is also well-understood that with skeletal expansion, we improve nasal airway patency [47] and that both dental and skeletal expansion can create a larger oral cavity volume which can increase the size of the pharyngeal airway space [48–50] positively impacting our patient’s ability to breathe. With this new understanding of the role of the airway in development of malocclusions, and the potential long-term impact of such dento-skeletal malocclusions on our patient’s airway and health, it is imperative that we as orthodontists are screening for underlying airway issues, as well as designing our dental and orthodontic treatments to help whenever possible. Traditionally, our orthodontic solutions for aligning crowded teeth when within an insufficient alveolus were to extract permanent teeth as a compromise. This is often elected for as it is considered periodontally-friendly and does not try to force teeth to align into insufficient alveolar bone where it would likely cause attachment loss and recession. Although extraction therapy in these cases has the benefit of not stressing the current alveolus, it accepts the current arch widths which are often narrow to begin with. As stated previously, there are many correlations between narrow arch dimension, small oral cavity volume, small nasal and pharyngeal airway dimension, and airway issues. As research has shown, extraction of permanent teeth does not significantly alter the pre-treatment airway dimensions [51, 52] but if these dimensions were already small to begin with, we may have missed an opportunity to help create better airway and oral cavity dimensions by not extracting teeth, and instead, providing expansive movements. This is where surgically facilitated orthodontic therapies offer a new and exciting option for treatment planning in crowding cases. The option of augmenting the periodontium in conjunction with orthodontic therapy can help us not only to safely achieve expansive dental movements and prevent possible periodontal recession, but to also pursue treatment that may have a positive impact on our patient’s oral cavity volume and airways.

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Another indication for surgically facilitated orthodontic techniques for improvement of the airways would be in conjunction with maxillary skeletal expansion, particularly in adults. One of the most exciting and evolving new arenas of airway-driven therapy in orthodontics is expansion of the maxilla in non-growing, adult patients. We know from previous research that expansion of the maxilla in adults not only increases the oral cavity volume but has also shown to improve nasal air patency via both surgical (SARPE) [47] and non-surgical options (MARPE, MSE) [26]. The limitation, though, of how much we can expand the maxilla is the mandible because we need to maintain interdigitation of the mandibular teeth with the maxillary teeth. As the mandibular teeth can only expand by moving through the alveolus, this presents potential issues to expanding the mandibular arch dimension as it may push the limits of the alveolar bone, especially if it already has a thin phenotype. In these circumstances, SFOT augmentation of the alveolar bone in conjunction with orthodontic dental arch width expansion into the newly augmented periodontium can enable us to expand the maxilla to our desired width for airway improvement while maintaining proper occlusion with the mandibular arch. In summary, as orthodontists, we have an opportunity to help far beyond the straightness of our patients’ teeth. We are trained to not only to correct the malocclusions in front of us, but also to determine the potential underlying cause(s). With our understanding of the airway’s role in development of malocclusions and the potential long-term impact of such dento-skeletal malocclusions on our patient’s airway and health, it is imperative that we as orthodontists are not only screening for underlying airway issues, but also taking advantage of interdisciplinary treatment modalities such as SFOT to design our dental and orthodontic treatments to improve airway and health issues whenever possible.

Pre-surgical Orthodontic Preparation When planning orthodontic treatment in conjunction with surgically facilitated techniques, sequencing of treatment and timing are extremely important factors (Fig.  28). In order to maximize the beneficial effects of accelerated tooth movement along with the benefits of augmented hard and soft tissues, we must plan our cases with increased interdisciplinary communication and efficiency. Just as no two orthodontic cases are the same from a tooth movement standpoint, there are increased complexities that must be considered when planning and executing surgically facilitated orthodontic treatment including location(s) of surgically facilitated ­techniques, timing of surgical treatment, mechanics of tooth movement, and timing of auxiliary restorative therapies.

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 actors for Determining the Location F of Surgical Intervention(s) As mentioned previously, the use of CBCT and verified treatment simulation software is invaluable when planning and executing interdisciplinary orthodontic treatment, particularly when deciding upon the locations of needed surgical intervention. In many cases, we can look to the CBCT images and simulations to decide where there will be insufficient alveolar bone to accomplish our desired tooth movements and then decide where we need corticotomies, hard and soft tissue grafting (Fig. 29). Our level of planning the location of surgical intervention should not stop there, though, as we must also look at the areas where we want to utilize the RAP effect and areas where we do not want the RAP effect to take place. Research has shown that the RAP effect extends 8 mm from the site of the cortical injury [53] and that increased depth and extent of cortical injury give a Fig. 28  Sequencing for SFOT

more profound RAP effect [54]. In surgical areas, we can expect roughly 50% faster tooth movement [55] than in areas that do not have surgical interventio.  Therefore, we can design our treatment to develop an alveolar bone-based anchorage system where the non-surgical areas do not move as much as the surgically-augmented alveolar areas. This would behave similar to traditional orthodontic anchorage systems of transpalatal arches, stopped archwires, etc. A common example of this would include re-opening previous extraction spaces. If we want to advance the anterior dentition and maintain the current posterior tooth positioning, we will want to design treatment that utilizes corticotomies and hard and soft tissue grafting in the anterior region while leaving the posterior region without surgical augmentations. Another example of this phenomena would be, if we wanted to protract molars forward, possibly through missing premolar spaces. In this instance, we would want to leave the anterior tooth and alveolar anchorage segment untouched while New Patient Examination, Diagnostic Imaging (CBCT) CBCT Alveolar Bone analysis

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Fig. 29  Example of where to plan surgical intervention. (a) Pre-­ crowding; and (d) alveolar bone fenestration as resulting from tooth treatment visualization of crowding; (b) thin pretreatment alveolar bone movements demonstrating osseous grafting should be pursued in this in lower anterior; (c) simulation showing resolution of lower anterior area during treatment

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Fig. 30  Example of localized RAP effect to aid in protraction of MN teeth while leaving mandibular anterior teeth without SFOT to establish alveolar anchorage. (a, d) Pre-SFOT CBCT imaging showing that cortocotomies and osseous grafting were planned in the posterior region

only to allow for MN teeth to protract with the RAP effect and use the anterior dentition and alveolus as anchorage for protraction as it was outside of the RAP zone; (b, c) Post-SFOT images of space closure with protraction of lower molars

directing our surgical corticotomies and grafting in the posterior region to help aid in its efficiency of protraction (Fig. 30).

the lower arch, can complicate this as the roots may lack interradicular space to accomplish the desired corticotomies. In this circumstance, it may be desired to begin orthodontic tooth movement before periodontal surgery to align the roots and allow proper spacing for the corticotomies to be executed (Fig. 31). Then, after the periodontal surgery, we can then take advantage of the RAP effect to finish orthodontic treatment more efficiently as the roots are now in a better position to move into the newly grafted tissues. Another instance where pre-SFOT tooth alignment may be desired is during space closure of missing teeth. A common example of this would be a missing posterior tooth where protraction of the posterior dentition is desired. Commonly in this situation, the adjacent teeth may have tipped into the space of the missing tooth and need to be leveled prior to space closure. In this circumstance, it may be desired to wait until after the arch is leveled and aligned and you are

 actors for Determining Timing of Surgical F Intervention In addition to deciding the location of surgical therapies, it is important to decide the timing of surgical intervention. In many cases, we want to initiate surgical procedures at beginning of treatment to allow for adequate bone for initial tooth movements, as well as take advantage of the RAP effect. In these more straight-forward cases, the tooth roots should have good interradicular spacing in the areas of surgery where the corticotomies would be performed. Often, significant crowding in the  anterior region, especially on

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Fig. 31  Example of pre-surgical alignment of lower anterior teeth to make room for corticotomies. (a) Initial alignment of teeth and recession noted. (b, c) Initial CBCT showing thin/thin labial bone phenotype

and close root proximity. (d, e). Teeth and roots after alignment. Notice root alignment improvement prior to surgical osseous grafting and desired sites of osseous corticotomies

into a wire capable of supporting bodily space closure (eg. rectangular  stainless steel) rather than tipping forces. Waiting for surgical therapy in this case would not only allow for the RAP effect during space closure to shorten the time, but also allow for possible augmentation of the alveolar ridge at the same time to produce adequate bone thickness for protraction of teeth with large buccolingual root dimension (Fig. 32).

In the anterior region, it is common to encounter teeth with labial tipping. For example, if we have labially tipped lower incisors that we want to advance forward bodily into newly grafted alveolus to correct an overjet issue, we will want to design our mechanics with excess labial root torque. This could be accomplished in a fixed system by choosing high negative torque bracket prescription in the anterior or possibly bending excess labial root torque into the archwire in the incisor region. The same would be true for maxillary incisor advancement for correction of tight overjet in a class III tendency patient. In this case, we would want to add excess labial root torque while pushing the teeth into the new alveolar bone, either by choosing low torque value brackets, wire bending labial root torque into the archwire, or even flipping the brackets upside down to express the excess labial root torque rather than labial crown torque. In the posterior region where expansive movements may be desired, it is common to encounter excess curve of Wilson where the teeth need to be directed into buccal bone for correction. To accomplish buccal bodily movement efficiently after periodontal surgery, buccal root torque needs to be added to the expansive movements to prevent tipping of the teeth. This can be accomplished by adding progressive buc-

Mechanics of Tooth Movement With fixed appliances or clear aligner attachments in place, it is very important that our mechanics of tooth movement are executed efficiently after periodontal surgery has been completed to take advantage of the RAP effect and to direct the teeth into their desired position. Whether you  use fixed or clear aligner therapy to execute teeth movements, the most important mechanical consideration for moving teeth is in the ability to control the roots of the tooth into the area we want. To do this, it is imperative that we understand and account for what our bracket or clear aligner prescription is doing at the root torque level (Fig. 33).

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Fig. 32  Example of SFOT timed after tooth leveling and alignment to allow for protraction of molars (a) Pre-treatment. Previous extraction spaces that were not closed. (b) Thin alveolus in the area of desired molar protraction. (c) Pre-SFOT alignment of roots and dentition.

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cal root torque to the archwire along with expansion of the archform. When planning for posterior expansion, especially in the mandibular arch, it would be prudent to pick the proper wire archform from the start of treatment to accomplish this

Corticotomies and osseous grafting were performed on the buccal between the premolars and molars at this time. (d) Final space closure via protraction of the molars after 4 months of treatment time

efficiently. An example of this would be to place an upper archform in the lower arch at the first visit to help the teeth begin to align and upright into the new buccal bone. This would especially be necessary in the lower arch if maxillary skeletal expansion was accomplished and the lower archform needs to be expanded into new alveolus to coordinate with the new maxillary arch width. Lastly, the consideration for accelerated tooth movement should be part of planning mechanics of tooth movement with surgically facilitated orthodontics. Because teeth can accomplish movements faster, we need to see patients at reduced time intervals to take advantage of the RAP effect and progress patients through treatment faster. Research has shown that tooth movement can be up to 50% faster when SFOT is accomplished and therefore, we should adjust our appointment intervals accordingly. In most circumstances, we should not go longer than 2 weeks between wire changes and active orthodontic movements so that we are efficient during this time of rapid tooth movement.

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 lear Aligner System Implications C As many adult and adolescent orthodontic patients commonly present with alveolar deficiencies, clear aligners are often desired for our esthetically driven patients to accomplish their treatment. For SFOT cases, the use of clear aligners can be a useful tool, however, the mechanics of clear aligners can vary from those used with traditional fixed appliances. Therefore, important considerations must be made for clear aligner mechanics to efficiently move teeth and roots to the desired positions, specifically in the areas of root movements, attachment design, overcorrections, and timing of tray changes. As with fixed appliances in SFOT cases, particular attention needs to be paid to the movement of the roots as we move teeth into areas of augmented alveolar bone. Clear aligner therapy has advanced significantly in the predictability of tooth movements, however, when planning our clear aligner prescription, it is still often necessary to add excess root torque, overcorrection, and supporting attachments to help facilitate bodily movements of teeth into the desired location [56]. When working up your clinical simulated outcome for clear aligners, it is helpful to look at each tooth and region’s movements as a force diagram where we design appropriate movements for correction, rather than just align teeth in the simulation. An example of clear aligner planning of surgically facilitated orthodontic therapy  in the posterior arch would be if dental expansion is desired. In the prescription for this movement, we would want to first add overcorrection (excess expansion) in our virtual plan as the clinical result often does not achieve the virtual outcome with expansion [57, 58]. Posterior expansion is most predictable in the premolar region, so less overcorrection is necessary (~10%) there and

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more over-expansion is desired in the molar region (20– 30%). Secondly, to make sure that teeth are not tipping with expansion, it is necessary to add excess buccal root torque while expanding (~10°). To achieve this overcorrection, it is necessary to have as much control of the tooth and root as possible and so placement of custom attachments is a must for doctors to control the outcome rather than trusting the technician’s attachment suggestions. To add excess buccal root torque, it would be advised to add “3mm wide, horizontal, gingival beveled attachments” to the buccal surface of the premolar teeth and “4mm wide, horizontal, gingival beveled attachments” to the buccal surface of the molar posterior teeth to control the molars from tipping during expansive movements (Fig. 34). Current clear aligner software systems allow you to dictate your own arch dimensions, root torque, and attachment design on teeth and so it is imperative that we, as the doctor, command the treatment planning with respect to these areas. An example of clear aligner planning of surgically facilitated orthodontic therapy in the anterior would be if teeth are desired to be advanced in the labial direction bodily. Examples of this would be anterior tooth alignment, lower anterior advancement for class II overjet correction, or maxillary incisor advancement for class III tendency overjet correction. In each of these circumstances, similar to the posterior, we would also want to add overcorrection of the desired tooth movement, excess root torque, and supporting attachments. If labial bodily tooth and root movement into a surgically augmented alveolus is desired in an expansive orthodontic plan, it is necessary to add “excess labial root torque” during movement. The degree of excess root torque should correspond to the degree that the tooth is currently proclined. For example, if a tooth has a near normal proclina-

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Fig. 34 Example of Invisalign treatment with programmed over expansion and excess buccal root torque coupling of forces. (a–c) Pretreatment Invisalign set up with 3 and 4 mm buccal, gingivally beveled horizontal attachments on upper and lower premolars and molars

to aid in expression of excess buccal root torque. (d–f) Final set up projection of over expanded upper and lower arches with expression of excess buccal root torque. Note the gingival contour mimicking projected excess buccal root torque

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tion, adding 10° of excess labial root torque would be appropriate, but if the teeth are significantly proclined, it may be advised to add 20–30° of excess labial root torque to achieve the final root angulation and tooth position. To reinforce the aligner’s programmed root movements, custom attachments will need to be added. In the maxillary anterior region, adding the widest “horizontal, gingival beveled” attachment possible will help to control the labial root torque. In the lower anterior region, we have the possibility of adding labial and lingual attachments with less occlusal interference than in other regions. To maintain labial root torque, adding the widest “horizontal, gingival beveled” attachment to the labial surface and the widest “horizontal occlusally beveled” attachment to the lingual surface would facilitate significant control of the root torque as a moment of force that would drive the root labially. Once again, as the doctor, we can control the efficiency of tooth movements with our acumen of treatment design. Lastly, the interval at which we progress through clear aligner trays should be adjusted to account for the RAP effect and accelerated treatment. Current literature has shown that in non-SFOT cases, it is predictable to achieve tooth movements with 7-day intervals of wearing each tray before progressing to the next [59]. Due to the nearly 50% increase in tooth movement during the RAP phase of SFOT treatment, it would be advised to design our treatment plan to accommodate tray changes every 3  days to take full advantage of accelerated tooth movement and efficiency of treatment.

 ommunication to Specialists Flow for SFOT C Patients Finally, in our pre-surgical therapy, it is important that we communicate with to our interdental team the goals, timing, and surgical needs for our patients. The following case

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 ase #1: Case Set Up and Communication C for SFOT to Relieve Excessive Anterior Crowding and Improve Oral Cavity Volume in a Skeletally Mature Adult The following is an example of a 53-year-old male who was referred with a chief complaint of crowding, tooth wear, recession, and airway sleep concerns (Fig. 35). Upon exam, he had clicking and popping TMJs but no pain. CBCT and MRI imaging were ordered for the patient to assess his TMJ, airway, and alveolar bone phenotypes, and a case simulation was accomplished to assess the impact of non-extraction on the periodontium. His TMJ analysis showed stability at his condyles as well as only mild disc displacement with nearly adequate coverage on his MRI confirming stability. His airway assessment showed a subnormal pharyngeal airway, slight nasal obstruction, and low tongue posture (Fig.  36). His skeletal and dental patterns demonstrated narrow transverse arch dimension and a slight class III pattern. Finally, when assessing his alveolar bone phenotypes, he showed thin/thin labial alveolar phenotypes in the maxillary and mandibular anterior sextants, as well as thin/thick p­ henotypes in the maxillary and mandibular buccal posterior sextants (Fig. 37). The goals of his care were to expand his oral cavity volume for proper tongue space and potential airway improvement and therefore, extraction orthodontics were not elected for. After completing his non-extraction treatment simulation, it was determined that there is insufficient bone in the mandibular and maxillary anterior regions and high potential for clinical attachment loss with posterior expansion due to thin bone phenotypes on the buccal. The patient

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Fig. 35 (a) Intra- and extraoral photos showing pretreatment recession and lower anterior crowding of dentition. (b) Dental casts showing subnormal transverse measurements in both the maxilla and mandible

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Fig. 36 (a) CBCT images showing stability of TMJs at the hard tissue level. (b) MRI images confirming disc coverage of the right and left condyles. (c) CBCT image showing subnormal pharyngeal airway and

low tongue posture. (d) CBCT showing nasal obstruction and narrow maxillary width

was presented with options of orthognathic surgical intervention with maxillary advancement and expansion to increase maxillary width and A-P position as well as SFOT in the areas of thin alveolar bone but declined orthognathic surgery after consultation. After the decision was made for non-surgical expansion, a treatment simulation was completed and then used to communicate to the interdisciplinary team that to accomplish our expansion and airway directed

goals, bone and soft tissue augmentation would be needed in the maxillary and mandibular posterior areas as well as the areas of thin alveolar bone in the anterior sextants (Figs. 38 and 39). In this example, CBCT diagnosis and treatment simulations allowed our team and patient to understand the periodontal surgical needs to accomplish the goals of treatment.

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Fig. 37 (a) CBCT showing MX thick/thin buccal alveolar phenotypes. (b) Thin/thin labial alveolar phenotypes at tooth #24. (c) Thick/thin phenotype at #25. (d–e) Thin phenotypes on the labial of #8 and 9

Fig. 38  Examples showing pre-treatment smile display and alveolar bone levels in SureSmile simulation software

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 ase #2: Class III Patient with Orthognathic C Surgical Plan The following is an example of a 23-year-old male who was referred with a chief complaint of an underbite. Upon exam, he did not exhibit TMJs noise or symptoms but did complain of nasal breathing issues (Fig. 40). CBCT and MRI imaging were ordered for the patient to assess his TMJ, airway, and alveolar bone phenotypes and a case simulation was accomplished to assess the impact of orthognathic surgical ­correction of his class III malocclusion and non-extraction orthodontic therapy on the periodontium. His TMJ analysis showed stability at his condyles on his CBCT.  His airway assessment showed significant nasal obstruction, subnormal pharyngeal airway  dimension,  and low tongue posture (Fig. 41) The most dramatic findings were seen when assessing his alveolar bone phenotypes. Although his clinical photos showed what looked like normal gingival tissue with only

mild recession in the mandibular anterior, his CBCT showed thin/thin labial and lingual alveolar phenotypes in the mandibular anterior sextants. He also showed thick/thin alveolar bone in the maxillary posterior region (Fig. 42). After completing his non-extraction treatment simulation, it was determined that there is insufficient bone in the mandibular anterior and maxillary posterior regions and high potential for clinical attachment loss with alignment of the dentition (Figs. 43 and 44). The patient was presented with options of orthognathic surgical bi-maxillary surgery as well as the necessity for SFOT in the areas of thin alveolar bone to allow for safe alignment of his teeth and stability of his result. After seeing his diagnostics, the patient accepted all treatment recommendations and began interdisciplinary therapy. In this example, CBCT diagnosis and treatment simulations allow our team and patient to see that there were significant risks to movement of teeth and that periodontal surgical therapy was needed to accomplish the goals of treatment safely.

Fig. 39  Example predicted alveolar bone and root interface after non-­ extraction orthodontic therapy after accomplishing alignment and smile goals using a standard MBT prescription straight wire system. These

images are used as communication to periodontal surgeons of where bone augmentation is indicated to accomplish this treatment plan using SureSmile simulation software

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Fig. 40 (a) Intra- and extraoral photos showing pretreatment class III skeletal and dental relationship with anterior crossbite and clinically apparent mild recession. (b) Dental casts showing normal transverse measurements in both the maxilla and mandible

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Fig. 41 (a) CBCT images showing stability of TMJs at the hard tissue level. (b) Lateral cephalograph showing class III skeletal pattern. (c) CBCT image showing constricted pharyngeal airway and low tongue

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posture. (d) CBCT showing nasal septum deviation, turbinates obstruction, and sinus inflammation

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Fig. 42 (a) CBCT showing MX thick/thick buccal and palatal alveolar phenotypes. (b, c) Thin/thin labial and lingual alveolar phenotypes in the mandibular anterior. (d, e) Thick/thick phenotypes in the maxillary anterior region

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Fig. 43  Examples of showing pre-treatment smile display and alveolar bone levels in SureSmile simulation software. Note the thin labial and lingual alveolar bone phenotypes in the mandibular anterior region

Fig. 44  Example predicted alveolar bone and root interface and smile esthetics after non-extraction alignment using a standard MBT prescription straight wire system of dentition with simulated maxillary advancement with mandibular bilateral sagittal split osteotomy for correction of mandibular asymmetry. These images are used as communi-

 ase #3: Class II Patient with MSE C and Bimaxillary Advancement Planned

cation to periodontal surgeons that bone augmentation would be indicated in the lower anterior as well as maxillary anterior and posterior to accomplish this treatment plan. SureSmile simulation software was used to create this simulation

cal advancement would be indicated for ideal improvement of her skeletal and airway dimensions and a tongue release and myofunctional therapy would be indicated for stability The following is an example of a 39-year-old female who of her surgical result. After assessing her alveolar bone phewas referred with a chief complaint of TMJ pain, crowding, notypes, a case simulation was accomplished to assess the recession, and airway sleep concerns (Fig. 45). Upon exam, impact of non-extraction pre-surgical therapy on the perishe had clicking and popping TMJs and pain of the level 7 odontium. After completing her non-extraction treatment out of 10 on the left and 5 on the right. CBCT and MRI imag- simulation with simulated MSE expansion and bi-maxillary ing were ordered for the patient to assess her TMJ, airway, advancement, it was determined that there is insufficient and cervical spine. Her initial findings showed that she had bone pre-treatment in the anterior mandible and posterior only mild disc displacement that reduced at incisal edge maxillary regions and high potential for clinical attachment position but with effusions present and so she had initial con- loss with the tooth movements needed for alignment of the servative splint therapy with a vitamin protocol developed by teeth (Figs. 48, 49, and 50). The patient was presented with Dr. Mark Piper (Fig. 46). After 12 months of splint and vita- options of MSE palatal expansion to increase maxillary min therapy, her pain had resolved, and her joints were re-­ width non-surgically as well as SFOT in the areas of thin imaged with MRI demonstrating her effusions had resolved alveolar bone and then bimaxillary advancement, all while (Fig. 47). At this time, she was cleared for orthodontic ther- continuing to manage her TMJ issues. She agreed to all apy and new CBCT images were taken to confirm her orth- phases of treatment and began treatment. Brackets were odontic plan. Her airway findings showed nasal obstruction, placed prior to SFOT hard and soft tissue augmentation and a narrow maxilla, subnormal pharyngeal airway dimension, tooth movement began 1 week after surgery (Fig. 51). In this and a significant tongue restriction with low posture. Her example, CBCT diagnosis and treatment simulations allowed narrow palate, large skeletal class II and bi-maxillary retru- our team and patient to understand the benefits of treatment sion, and concordant small pharyngeal airway dictated that and ultimately accept the highest standard of treatment we expansion of her maxilla and bimaxillary orthognathic surgi- could offer as an interdisciplinary team for her.

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Fig. 45 (a) Intra- and extraoral photos showing pretreatment recession and lower anterior crowding of dentition. (b) Dental casts showing subnormal transverse measurements in both the maxilla and mandible

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Fig. 46 (a) CBCT images showing initial left condylar instability at the hard tissue level. (b) MRI showing mild disc displacement at right and left condyles. (c) CBCT image showing subnormal pharyngeal air-

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way and low tongue posture. (d) CBCT showing nasal obstruction and narrow maxillary width. (e) Initial tongue range of motion signifying a significant tongue anterior and posterior restriction

192 Fig. 47 (a) Initial MRI STIR image showing effusion at right condyle. (b) Initial MRI STIR image showing effusion at left condyle. (c) Post-splint therapy follow-up MRI STIR image showing reduction of right effusions. (d) Post-splint therapy follow-up MRI STIR image showing reduction of left effusion

D. McDonald

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Fig. 48 (a) CBCT showing MX thick/thin buccal alveolar phenotypes in the maxillary posterior and thin/thin buccal alveolar phenotypes in the mandibular posterior. (b, c) Thin/thin alveolar phenotypes at the

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lower anterior dentition. (d, e) Thick/thin alveolar phenotypes on the labial of #8 and 9

Fig. 49  Examples showing pre-treatment smile display and alveolar bone levels in SureSmile simulation software

Pre-surgical Orthodontic Therapy

Fig. 50  Example predicted alveolar bone and root interface using SureSmile software after MSE expansion, bimaxillary orthognathic surgical advancement, and non-extraction orthodontic alignment using a standard MBT description straight wire system. These images are

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used as communication to periodontal surgeon that bone augmentation would be indicated in the lower arc as well as maxillary posterior sextants to accomplish this treatment plan

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Fig. 51 (a) SureSmile initial alveolar bone and root interface. (b–d) Brackets placed and alveolar bone seen during surgical flap reflection in lower arch. (e–g) Osseous grafting in maxillary and mandibular arches

along with connective tissue grafting. Surgery and photos courtesy of periodontist Dr. Curtis Pino, Albuquerque, NM. Orthodontist: Drew McDonald, DDS, MS. Periodontist: Curtis Pino, DDS, MSD

 anaging Risk: What Happens When M We Don’t Look

alveolar bone prior to treatment and plan our mechanics accordingly, we leave ourselves open for unsuccessful treatment results, significant complications, and unhappy patients who may seek litigation (Figs. 52 and 53). If we are striving to provide the best treatment for our patients, we must accept that interdisciplinary care is necessary and that many patients, especially adults, will need surgically facilitated orthodontic treatment as part of their plan.

As demonstrated in this chapter, assessment of the periodontal alveolar phenotypes with CBCT is crucial before starting orthodontic tooth movement and is crucial for informing the patient and our interdisciplinary team of the potential risks involved in treatment. When we do not critically assess the

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Fig. 52  Example of skeletally mature transfer patient who underwent unsuccessful correction of her significant skeletal class II with non-­ extraction, non-surgical therapy. Notice the lower dentition is proclined with minimal alveolar bone after wearing heavy class II elastics

Fig. 53  Example of skeletally mature transfer patient who underwent lower dentition is deficient in alveolar bone after resolution of crowding unsuccessful correction of her significant skeletal class II with non-­ and elastics. CBCT courtesy of Dr. Curtis Pino, Albuquerque, NM extraction, non-surgical clear aligner therapy. Notice the upper and

Closing Remarks: The Role of the Orthodontist as the Dentoalveolar/ Alveoloskeletal Bone Engineer As we move forward as an orthodontic profession, we must understand and embrace our role as engineers of the alveolar bone. In our young patients, we have the opportunity to intercept deficiencies in the alveolus and create adequate bone with early expansion and arch development. In our adolescent and adult patients, we have new techniques that allow us to create a better alveolus when we see deficiencies, with expansion the maxilla, orthognathic surgeries, and surgically facilitated orthodontic augmentation of bone and soft tissues. The ability to plan our treatment to create a better alveolus, rather than accept it, is a game-changer when it comes to treatment planning and execution of interdisciplinary orthodontic treatment. When we see crowding and narrow arches, we should not be automatically thinking of traditional extraction orthodontics and accepting the current alveolus, but we must consider that we have new tools and possibilities for expansion and alveolar augmentation to achieve our esthetic, functional, and airway-driven goals. The bottom line, though, is that we must critically evaluate the alveolus before treatment to be able to address it. Like never before, we have advanced diagnostic ability with CBCT and treatment simu-

lation technologies to help guide us in our treatment decisions and communication with our patients and team. In today’s orthodontic world, with our increased understanding of how our treatment can positively impact the health of our patients, and techniques like SFOT at our fingertips to achieve our goals, we should not resort to the techniques of our past, but we must push forward to provide the highest standard of care for our patients and pursue more than just straight teeth.

References 1. Schellhas KP, Piper MA, Bessette RW, Wilkes CH.  Mandibular retrusion, temporomandibular joint derangement, and orthognathic surgery planning. Plast Reconstr Surg. 1992;90(2):218–29. discussion 230–2 2. Harvold EP, et  al. Primate experiments on oral respiration. Am J Orthod. 1981;79(4):359–72. 3. Pedrazzi ME. Treating the open bite. J Gen Orthod. 1997;8(1):5–16. 4. Chaison JB, et al. Bone volume, tooth volume, and incisor relapse: a 3-dimensional analysis of orthodontic stability. Am J Orthod Dentofac Orthoped. 2010;138(6):778–86. 5. Flores-Mir C, et  al. Longitudinal study of temporomandibular joint disc status and craniofacial growth. Am J Orthod Dentofac Orthoped. 2006;130(3):324–30. 6. Zúñiga-Herrera ID, et  al. Malocclusion complexity as an associated factor for temporomandibular disorders. A case-control study.

Pre-surgical Orthodontic Therapy Cranio J Craniomandib Pract. 2021:1–6. https://doi.org/10.1080/08 869634.2020.1868907. 7. Mark P. Temporomandibular Joint Imaging. In: Kerstein RB, editor. Handbook of research on clinical applications of computerized occlusal analysis in dental medicine. Pennsylvania: IGI Global; 2020. p. 582–697. 8. Pirilä-Parkkinen K, et al. Dental arch morphology in children with sleep-disordered breathing. Eur J Orthopod. 2009;31(2):160–7. 9. Lobbezoo F, et  al. International consensus on the assessment of bruxism: Report of a work in progress. J Oral Rehabil. 2018;45(11):837–44. 10. Behrents RG, et  al. Obstructive sleep apnea and orthodontics: an American Association of Orthodontists White Paper. Am J Orthod Dentofac Orthop. 2019;156(1):13–28. 11. Netzer NC, Stoohs RA, Netzer CM, Clark K, Strohl KP. Using the Berlin Questionnaire to identify patients at risk for the sleep apnea syndrome. Ann Intern Med. 1999;131(7):485–91. 12. Johns WM. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep. 1991;14(6):540–5. 13. Chung F, Yegneswaran B, Liao P, Chung SA, Vairavanathan S, Islam S, Khajehdehi A, Shapiro CM.  STOP questionnaire: a tool to screen patients for obstructive sleep apnea. Anesthesiology. 2008;108(5):812–21. 14. Zimmerman JN, Vora SR, Pliska BT.  Reliability of upper airway assessment using CBCT. European journal of orthodontics. Eur J Orthod. 2019;41(1):101–8. 15. Chaudhry U, Cohen JR, Al-Samawi Y.  Use of cone beam computed tomography imaging for airway measurement to predict obstructive sleep apnea. Cranio J Craniomandib Pract. 2022;40(5); 418–24. 16. Jang SJ, Cha BK, Ngan P, Choi DS, Lee SK, Jang I. Relationship between the lingual frenulum and craniofacial morphology in adults. Am J Orthod Dentofac Orthoped. 2011;139(4 suppl):361–7. 17. Yoon AJ, Zaghi S, Ha S, Law CS, Guilleminault C, Liu SY.  Ankyloglossia as a risk factor for maxillary hypoplasia and soft palate elongation: A functional - morphological study. Orthod Craniofac Res. 2017;20(4):237–44. 18. Vaz AC, Bai PM. Lingual frenulum and malocclusion: an overlooked tissue or a minor issue. Indian J Dent Res. 2015;26(5):488–92. 19. Jalaly T, Ahrari F, Amini F. Effect of tongue thrust swallowing on position of anterior teeth. J Dent Res Dent Clin Dent Prospects. 2009;3(3):73–7. 20. Zaghi S, Shamtoob S, Peterson C, Christianson L, Valcu-Pinkerton S, Peeran Z, Fung B, Kwok-Keung Ng D, Jagomagi T, Archambault N, O'Connor B, Winslow K, Lano M, Murdock J, Morrissey L, Yoon A.  Assessment of posterior tongue mobility using lingual-­ palatal suction: Progress towards a functional definition of ankyloglossia. J Oral Rehabil. 2021;48(6):692–700. 21. Larson BE, Vaubel CJ, Grünheid T.  Effectiveness of computer-­ assisted orthodontic treatment technology to achieve predicted outcomes. Angle Orthod. 2013;83(4):557–62. 22. Mandelaris GA, Vence BS, Rosenfeld AL, Forbes DP. A classification system for crestal and radicular dentoalveolar bone phenotypes. Int J Periodontics Restorative Dent. 2013;33(3):289–96. 23. Mandelaris GA, Neiva R, Chambrone L.  Cone-beam computed tomography and interdisciplinary dentofacial therapy: an american academy of periodontology best evidence review focusing on risk assessment of the dentoalveolar bone changes influenced by tooth movement. J Periodontol. 2017;88(10):960–77. 24. Zachrisson BU, Alnaes L.  Periodontal condition in orthodontically treated and untreated individuals, I: Loss of at- tachment, gingival pocket depth and clinical crown height. Angle Orthod. 1973;43:402–11.

195 25. Martins RP, da Rosa Martins JC, Martins LP, Buschang PH. Skeletal and dental components of Class II correction with the bionator and removable headgear splint appliances. Am J Orthod Dentofac Orthop. 2008;134(6):732–41. 26. Storto CJ, Garcez AS, Suzuki H, Cusmanich KG, Elkenawy I, Moon W, Suzuki SS.  Assessment of respiratory muscle strength and airflow before and after microimplant-assisted rapid palatal expansion. Angle Orthod. 2019;89(5):713–20. 27. MacGinnis M, Chu H, Youssef G, Wu KW, Machado AW, Moon W.  The effects of micro-implant assisted rapid palatal expansion (MARPE) on the nasomaxillary complex--a finite element method (FEM) analysis. Prog Orthod. 2014;15(1):52. 28. Johnston CD, Burden DJ, Stevenson MR. The influence of dental to facial midline discrepancies on dental attractiveness ratings. Eur J Orthod. 1999;21(5):517–22. 29. Pinho S, Ciriaco C, Faber J, Lenza MA. Impact of dental asymmetries on the perception of smile esthetics. Am J Orthod Dentofacial Orthop. 2007;132(6):748–53. 30. Sarver MD.  The importance of incisor positioning in the esthetic smile: the smile arc. Am J Orthod Dentofac Orthop. 2001;120(2):98–111. 31. Jeelani W, Fida M, Shaikh A. The maxillary incisor display at rest: analysis of the underlying components. Dental Press J Orthod. 2018;23(6):48–55. 32. Mackley JR. An evaluation of smiles before and after orthodontic treatment. Angle Orthod. 1993;63(3):183–90. 33. Kokich VO Jr, Kiyak HA, Shapiro PA. Comparing the perception of dentists and lay people to altered dental esthetics. J Esthet Dent. 1999;11(6):311–24. 34. Resnick CM, Kim S, Yorlets RR, Calabrese CE, Peacock ZS, Kaban LB. Evaluation of Andrews’ analysis as a predictor of ideal sagittal maxillary positioning in orthognathic surgery. J Oral Maxillofac Surg. 2018;76(10):2169–76. 35. Cao L, Zhang K, Bai D, Jing Y, Tian Y, Guo Y.  Effect of maxillary incisor labiolingual inclination and anteroposterior position on smiling profile esthetics. Angle Orthod. 2011;81(1):121–9. 36. Ricketts RM.  A foundation for cephalometric communication. Original Article. 1960;46(5):330–57. 37. Martin AJ, Buschang PH, Boley JC, Taylor RW, McKinney TW. The impact of buccal corridors on smile attractiveness. Eur J Orthod. 2007;29(5):530–7. 38. Linder-Aronson S.  Adenoids: Their effect on mode of breathing and nasal airflow and their relationship to characteristics of the facial skeleton and the denition. A biometric, rhino-manometric and cephalometro-radiographic study on children with and without adenoids. Acta Oto-Laryngol. Supplementum. 1970;265:1–132. 39. McNamara AJ.  Maxillary transverse deficiency. Am J Orthod Dentofac Orthop. 2000;117(5):567–70. 40. Glass TR, Tremont T, Martin CA, Ngan PW. A CBCT evaluation of root position in bone, long axis inclination and relationship to the WALA Ridge. Semin Orthod. 2019;25(1):24–35. 41. Koo YJ, Choi SH, Keum BT, Yu HS, Hwang CJ, Melsen B, Lee KJ. Maxillomandibular arch width differences at estimated centers of resistance: Comparison between normal occlusion and skeletal Class III malocclusion. Korean J Orthod. 2017;47(3):167–75. 42. Manfredini D, Segù M, Arveda N, Lombardo L, Siciliani G, Rossi A, Guarda-Nardini L.  Temporomandibular joint disorders in patients with different facial morphology. a systematic review of the literature. J Oral Maxillofac Surg. 2016;74(1):29–46. 43. Trotman CA, McNamara JA Jr, Dibbets JM, van der Weele LT.  Association of lip posture and the dimensions of the tonsils and sagittal airway with facial morphology. Angle Orthod. 1997;67(6):425–32.

196 44. Ramires T, Maia RA, Barone JR. Nasal cavity changes and the respiratory standard after maxillary expansion. Braz J Otorhinolaryngol. 2008;74(5):763–9. 45. Cistulli PA. Craniofacial abnormalities in obstructive sleep apnoea. Implications for treatment. Respirology. 1996;3:167–74. 46. Cistulli PA, Richards GN, Palmisano RG, Unger G, Sullivan CE. Influence of maxillary constriction on nasal resistance and sleep apnea severity in Marfan’s syndrome. Chest. 1996;110:1184–8. 47. Zambon CE, Ceccheti MM, Utumi ER, Pinna FR, Machado GG, Peres MP, Voegels RL. Orthodontic measurements and nasal respiratory function after surgically assisted rapid maxillary expansion: an acoustic rhinometry and rhinomanometry study. Int J Oral Maxillofac Surg. 2012;41(9):1120–6. 48. Cistulli PA, Palmisano RG, Poole MD.  Treatment of obstructive sleep apnea syndrome by rapid maxillary expansion. Sleep. 1998;21(8):831–5. 49. Mehta S, Wang D, Kuo CL, Mu J, Vich ML, Allareddy V, Tadinada A, Yadav S. Long-term effects of mini-screw-assisted rapid palatal expansion on airway. Angle Orthod. 2021;91(2):195–205. 50. Rana SS, Kharbanda OP, Agarwal B.  Influence of tongue volume, oral cavity volume and their ratio on upper airway: a cone beam computed tomography study. J Oral Biol Craniofac Res. 2020;10(2):110–7. 51. Hu Z, Yin X, Liao J, Zhou C, Yang Z, Zou S. The effect of teeth extraction for orthodontic treatment on the upper airway: a systematic review. Sleep Breath. 2015;19(2):441–51.

D. McDonald 52. AlKawari HM, AlBalbeesi HO, Alhendi AA, Alhuwaish HA, Al Jobair A, Baidas L. Pharyngeal airway dimensional changes after premolar extraction in skeletal class II and class III orthodontic patients. J Orthod Sci. 2018;7:10. 53. Murphy KG, Wilcko MT, Wilcko WM, Ferguson DJ. Periodontal accelerated osteogenic orthodontics: a description of the surgical technique. J Oral Maxillofac Surg. 2009;67(10):2160–6. 54. Cohen G, Campbell PM, Rossouw PE, Buschang PH.  Effects of increased surgical trauma on rates of tooth movement and apical root resorption in foxhound dogs. Orthod Craniofac Res. 2010;13(3):179–90. 55. Gil A, Haas OL Jr, Méndez-Manjón I, Masiá-Gridilla J, Valls-­ Ontañón A, Hernández-Alfaro F, Guijarro-Martínez R.  Alveolar corticotomies for accelerated orthodontics: a systematic review. J Craniomaxillofac Surg. 2018;46(3):438–45. 56. Glaser B.  The insider’s guide to invisalign treatment: a step-by-­ step guide to assist you with your clincheck treatment plans. Sacramento, CA: 3L Publishing; 2017. 57. Morales-Burruezo I, Gandía-Franco JL, Cobo J, Vela-Hernández A, Bellot-Arcís C. Arch expansion with the Invisalign system: efficacy and predictability. PLoS One. 2020;15(12):e0242979. 58. Zhou N, Guo J.  Efficiency of upper arch expansion with the Invisalign system. Angle Orthod. 2020;90(1):23–30. 59. Al-Nadawi M, Kravitz ND, Hansa I, Makki L, Ferguson DJ, Vaid NR. Effect of clear aligner wear protocol on the efficacy of tooth movement. Angle Orthod. 2021;91(2):157–63.

Management of Skeletal Class II Malocclusion: Historical Challenges and New Opportunities Kensuke Matsumoto

Orthodontic Boundary Limits Proffit and Ackerman [1] in 1982 introduced a diagram of the “envelope of discrepancy” in order to address the challenge of the limitation of tooth movement. They estimated that, with orthodontic tooth movement alone, the limits of extrusion, retraction, intrusion, and protraction of mandibular incisors are 2 mm, 3 mm, 4 mm, and 5 mm, respectively. However, these parameters were more for manifesting the principle of limitation and were not determined by measurements or specific anatomic boundaries. When it was published, three-dimensional diagnosis with a cone-beam computed tomographic (CBCT) was not available. The limits of orthodontic tooth movement which are determined by anatomic and biologic limits may be considered as “orthodontic boundary limits.” Anatomic limits are defined by the craniofacial, skeletal, dentoalveolar, and dentogingival complex. These limits should be evaluated prior to any treatment three dimensionally. Biologic limits are explained by the functional and structural response that periodontal tissue can tolerate without compromising dur-

ing and/or after the tooth movement, which provide longterm stability from periodontal and orthodontic perspectives. The orthodontic boundary limits are not static but dynamic and modifiable in corporate with periodontal surgeries. These limits should be taken into account during the treatment planning and may dictate the amount, types, and goals of tooth movement. When force is applied to teeth by any appliances within the biologically acceptable limits, the gingival and alveolar bone response without changing the attachment level. On the contrary, invading the boundary limits with inadequate treatment planning can create undesired periodontal consequences, resulting in dentoalveolar bone deficiency (dehiscence and fenestrations) and at worst, attachment loss (gingival recessions) (Fig. 1). The concept of orthodontic boundary limits is not widely recognized, and much research has not been conducted on this fundamental topic. We rarely know what the limits of tooth movement are, how to determine the parameters, and how orthodontic boundary limits are influenced by orthodontic and/or periodontal therapy.

K. Matsumoto (*) Matsumoto Orthodontics & Periodontics, Wilmington, NC, USA © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 G. A. Mandelaris, B. S. Vence (eds.), Surgically Facilitated Orthodontic Therapy, https://doi.org/10.1007/978-3-030-90099-1_13

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Fig. 1 (a) Pre-treatment intraoral frontal photograph demonstrating crowding, thick flat biotype, and wide width of keratinized gingiva on mandibular incisors. (b) Expanding mandibular arch with fixed appli-

ances and proclining the incisors resulted in reducing the width of keratinized gingiva, converting to thin scalloped biotype, and creating attachment loss during the orthodontic treatment

 iagnosis of Craniofacial and Dentoalveolar D Complex

regard to the appropriateness of taking CBCT images, “Clinicians should use professional judgment in the prescription and performance of CBCT examinations by ­ consulting recommendations from available CBCT guidelines and by considering the specific clinical situation and needs of the individual patient.” [7, 8]

Conventional periapical, panoramic, and cephalometric radiography have been used for orthodontic diagnoses and treatment planning [2, 3] despite the fact that they have geometric distortion and anatomical superimposition. Currently, the use of CBCT imaging has made it possible to visualize the related craniofacial and dentoalveolar structures with higher resolution in three dimensions. This has improved the overall diagnostic efficacy and made early diagnosis possible for certain clinical conditions. However, there was controversial opinions of taking CBCT imaging for comprehensive orthodontic assessment [4, 5]. Interestingly, history repeats itself. Larson [4] quoted the Steiner’s article [6] in 1953, he challenged orthodontists with the following words: “The cephalometer is here to stay, and those of you who are not using cephalometrics in your everyday clinical practices must soon bow to its importance, accept the added burden it imposes, and master its mysteries if you are to discharge your full obligation to your patients.” Steiner’s statement could easily be applied to the use of CBCT today. It should be emphasized that CBCT imaging is considered as a supplemental imaging technique only when practitioners expect that the diagnostic yield will benefit patient care, enhance patient safety, or improve clinical outcomes significantly [7]. Additionally, due to the difficulties to acquire the approval of extra radiation exposures from the institutional review board (IRB) academically, it is difficult to initiate and implement higher level, evidence-based studies regarding CBCT imaging such as randomized controlled and prospective studies in orthodontics. We still need much more research to comprehend how to utilize CBCT imaging to maximize the orthodontic outcomes. Therefore, with

2D vs 3D Imaging Orthodontic diagnosis, treatment plans, evaluation of growth and development, and assessment of treatment outcomes have traditionally been performed on the basis of clinical examination and records that consist of extraoral and intraoral images, dental casts (or digital models), and analysis of two-dimensional (2D) radiography such as panoramic and lateral cephalometric images. The inherent limitations of 2D radiography for the assessment of craniofacial and dentoalveolar complex in orthodontics have been discussed for many years [9, 10]. They include magnification, distortion, artifacts, superimposition of anatomical details, and discrepancy between cephalometric analyses and clinical findings due to the difficulty of landmark identification. Furthermore, considering the characteristics of lateral cephalograms, there is little information in the transverse dimension. CBCT imaging has enhanced our ability to evaluate the morphology of the craniofacial and dentoalveolar complex. It allows the quantitative assessment of the transvers and alveolar bone dimensions. As a result of anatomical visibility and volumetric accuracy, the necessity of three-dimensional (3D) imaging is expanding in orthodontic diagnosis. In order to evaluate differences in the diagnosis and treatment planning of impacted maxillary canines between two imaging modalities, traditional 2D images and 3D volumet-

Management of Skeletal Class II Malocclusion: Historical Challenges and New Opportunities

ric images obtained from a CBCT scan were compared [11]. Twenty-seven percent of the cases that were planned with the 2D radiographs had different treatment plans after viewing the 3D CBCT images. They concluded that 2D and 3D images can produce different diagnoses and treatment plans. The similar result was reported [12]. According to Fuhrmann et al. [13], there is a general overestimation of the symphysial labiolingual bone width on the lateral cephalograms when compared with physical measurements of the actual specimens, and over 80% of defects identifiable in 3D images were not readily visible on the lateral cephalograms. Similarly, another research reported that alveolar bone thickness is always overestimated on cephalograms compared with CBCT-based measurements with the range from 0.3 to 1.3 mm [14]. Therefore, the outer lines of the alveolar process that are observed on lateral cephalograms could exhibit the superimposition of other structures. Dehiscences and/or fenestrations on anterior teeth could be possibly masked due to overestimating the thickness of the cortical plates. Two-dimensional radiography does not allow us to evaluate the important sites of the alveolar process properly (Fig. 2). The American Academy of Periodontology published the consensus statement on CBCT [15] and the review [16] focusing on risk assessment of the dentoalveolar bone changes influenced by tooth movement. In the consensus statement, CBCT imaging has demonstrated that changes occur to the buccal plate and general alveolar bone structure following orthodontic tooth movement. They concluded that CBCT imaging is the only radiographic modality with which such changes can be objectively detected and preoperative risk determined. In the review, in order to prevent periodontal complications or assess risks after orthodontic treatment, CBCT imaging can improve the periodontal diagnostic acumen regarding alveolar bone alterations influenced by orthodontic treatment. Furthermore, clinicians are better informed to determine risk assessment and develop preventative or interceptive periodontal augmentation (soft t­issue and/or bone augmentation) therapies for patients undergoing orthodontic treatment. In summary, 3D imaging provides us critical information in order to diagnose accurately, evaluate the anatomical structures that we need to consider prior to treatment planning, and improve the clinical outcomes of orthodontic treatment.

Efficacy of CBCT Accurate evaluation of alveolar bone height and thickness is important prior to periodontal and orthodontic treatments. Dimensional changes in alveolar bone have been found to be associated with orthodontic tooth movement, especially in

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skeletal Class II treatment due to excessive proclination of mandibular anterior teeth, often creating dehiscences and/or fenestrations around teeth. Research showed that dentoalveolar bone deficiency is not pathologic but a pre-existing condition. Therefore, measurements of alveolar bone height, thickness, and volume play critical roles not only in the initial assessment for tooth movement but also in the final evaluation after orthodontic treatment in order to provide long-term stability. Advantages of CBCT are visualization of anatomic structures in the three dimensions, precision for diagnosis, and accuracy of analysis. A number of studies have demonstrated that CBCT can be used to measure alveolar bone height and thickness with accuracy and reliability [17–19]. However, some research reported there was a systematic overestimation of the CBCT measurements and alerted that a severe dehiscence might not be as serious as the CBCT showed [20, 21]. Menezes et  al. [17] found excellent interexaminer and intraexaminer reproducibility of buccal and lingual bone plate thickness measurements in CBCT images on dried human mandibles and demonstrated good precision for voxel dimensions of 0.2, 0.3, and 0.4 mm. On the other hand, Leung et al. [20] reported that alveolar bone height can be measured to an accuracy of about 0.6 mm and the specificity was high at 0.95, but the sensitivity was low at 0.40 by using a voxel size of 0.38  mm. However, compared with CBCT of alveolar bone in vivo, direct assessment of dry skulls lacks the image of the periodontal apparatus (soft tissue); thus, it may result in drastic errors. To resolve this discrepancy, Timock et al. [18] evaluated human cadaver specimens. They found that mean absolute errors between CBCT at 0.3 mm voxel size and direct measurements of buccal bone height and buccal bone thickness were small (0.30 and 0.13 mm, respectively) and showed no statistically significant differences or bias to underestimate or overestimate. Interoperator reliability had great agreement for CBCT measurements of buccal bone height (0.98) and buccal bone thickness (0.91) while intraoperator reliability was high as interoperator correlations for CBCT buccal bone height (>0.97) and buccal bone thickness (0.90). In a current study with an 0.3-mm voxel size that was selected due to the balance of the amount of radiation exposure and clinical relevance [19], for intraoperator reliability, the mean absolute differences in alveolar bone thickness estimates were 0.24 mm with a Pearson correlation (0.93) and 0.44 mm with a correlation (0.91) for alveolar bone height. Between operators, the mean absolute difference was 0.29 mm (0.92) for the thickness, and 0.28 mm (0.95) for the height. The high correlation between and within operators suggested that these measurements were replicable and robust. The measurements of alveolar bone thickness and height may be accurate while the sensitivity might not be as high as the specificity. These different reports suggested that further attention should be paid to defining the

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Fig. 2  Comparison of the lateral cephalograms (a and b magnified mandibular anterior region of A) and CBCT imaging (c reconstructed 3D imaging and d a sagittal cross-section of the left mandibular central incisor from CBCT scans). CBCT imaging provides novel information, morphology of the symphysis, and the relationships between the alveo-

lar process and the incisors that are not discernible from 2D radiographs, which may impact treatment planning. The mandibular left central incisor is positioned labially, and the root is out from the alveolar process. There are severe concavities between the roots on the alveolar process

accuracy of CBCT measurements and evaluation. However, with careful assessment of each research, they might have been associated with variables in the study designs, such as the different subjects (hard tissue only with human dry skulls, hard and soft tissues with human cadavers, or patients), voxel sizes utilized for the CBCT measurements, CBCT manufactures, and software. In the latest systematic review, Li et al.

[22] reported that the mean differences between CBCT and direct physical measurements for alveolar bone height (mean difference = 0.03 mm) and alveolar bone thickness (mean difference  =  0.11  mm) were not statistically significant. They concluded that there is no significant difference between CBCT and direct measurements for the alveolar bone height and thickness.

Management of Skeletal Class II Malocclusion: Historical Challenges and New Opportunities

Orthodontics and Gingival Recession  imensional Changes of Dentoalveolar D Gingival Complex In orthodontics, the consideration of tooth movement is not only bone resorption and apposition but also the response of soft tissue. For instance, when pure extrusion is implemented on an intact tooth, the orthodontic force creates a tension on the dentoalveolar fibers, making them stretched and elongated. This extension of the fibers on the surface of the bone can lead to the new bone formation [23]. As a result, not only bone apposition on the cervical and apical parts of the alveolar bone but also increase in the width of keratinized gingiva, decrease of sulcus depth in a short-term, and movement of mucogingival junction occur [24]. In order to comprehend the tooth movement, the concept of “Dentoalveolar gingival complex” become essential. Dentoalveolar gingival complex consists of enamel, dentin, cementum, junctional epithelium, gingiva, alveolar mucosa, mucogingival junction, periosteum, alveolar bone, and periodontal ligament. These components are intricately connected with each other through homeostasis. Dimensions of the complex can be changed pre- and post-orthodontic treatment. In animal studies, following extensive bodily movement of incisors in a labial direction through the alveolar bone, most teeth clinically demonstrated some apical displacement of the gingival margin [25]. However, when evaluated histologically, there was no attachment loss, but alveolar bone resorption was found. Karring et  al. [26] concluded that dehiscences can be produced by labial tipping but bone will reform in such defects when the teeth are moved back to their original position without attachment loss.

 revalence of Gingival Recession: No P Orthodontic Treatment Prevalence of gingival recession is diverse in research due to the different criteria such as various age groups, regions, observation periods, or definition of recessions. In general, the prevalence and severity of gingival recession are less in children and increase with age. In Saudi Arabia, 1336 children aged 10–15 years, gingival recession was found in 9.9% of the patients [27]. In Germany, adolescents who were diagnosed as Class II div1 were investigated and the prevalence for teeth with gingival recession >0.5  mm was 1.1% [28]. The prevalence of gingival recession (≥1 mm) was 29.5% of the subjects and 2.9% of teeth in adolescents (14–19  year old) in Brazil [29]. In Sweden [30], 62% of the 15-year-old subjects presented gingival recession. The number of affected teeth per individual was low, one tooth in about 35% and

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teeth in 25% of the individuals. In untreated 17-year-olds, 8.7% of teeth had recessions in Finland [31]. In Israel, healthy patients (18–22  years old) who had routine dental examinations at a military dental center presented gingival recession in 14.6% of the subjects and in 1.6% of all examined teeth [32]. Focusing on mandibular incisors, the prevalence was 5% at age 7  years in Finnish children [31] and similar value (4.8%) was shown in Brazilian study [33]. Parfitt and Mjör [34] reported the prevalence of gingival recession in the mandibular central incisors was 7.7% in a group of 668 children aged 9–12  years. In high school children aged 14–19 years, gingival recession was noted in the mandibular incisors in 13.1% of 766 students, frequently in association with malposition of the teeth [35]. In Class II malocclusion, 7.7% of mandibular central incisors from 98 children exhibited gingival recession [36] and the highest prevalence (approximately 5.2%) was seen for the mandibular central incisors whom less than 1% exhibited gingival recession with a magnitude >2.0 mm, comparing with other teeth [28]. In the population above 30 years old, using data representative of the United States population (NHANES III), Albander and Kingman [37] reported that 22.5% of teeth exhibited at more than 3 mm of recession, 5.5% at more than 5  mm, respectively. They stated that the prevalence and extent of recession among untreated subjects increase steadily with age. Susin et at. [29] assessed untreated Brazilians (aged 14 years and older) and found that gingival recession ≥3 mm was 17.0% of teeth while recession ≥5 mm was 5.8% of teeth. Also, they mentioned that the prevalence, extent, and severity of recession correlated with age. Approximately, 96% of the subjects in their 30 to 39-year-­ old cohort demonstrated gingival recessions on at least 1 tooth, and 44.3% of teeth had recessions of 1 mm or more. In France, subjects (age range: 35 to 65 years) were evaluated and a total of 84.6% of the sample had at least one gingival recession. While gingival recession (1–3 mm) was 76.9% of the population, severe recession depths (>6 mm) were only found in 1.8% of the subjects [38]. A multivariate linear regression model showed that age was associated with the extent of gingival recession. In a long-term follow-up study with dental students [39], the prevalence of gingival recession was 85% and did not change after 10 years. Regarding gingival recession of mandibular incisors, 19.7% of mandibular central incisors had recessions of 1 mm or more in persons 30–55 years old while 49.7% had recessions in the group above 55 years old [37]. Depending upon research, the prevalence of very mild gingival recession has been reported up to 30% in young children. However, severe gingival recession seems to be less than 1%. In adults, the prevalence, extent, and severity of recession increase steadily with age. Yet, severe recession was only found in less than 10% of subjects or teeth. The

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data showed that higher prevalence was seen on mandibular central incisors.

Post-Orthodontic Treatment and Gingival Recession In children, there were no statistically significant differences between the treated (with premolars extraction) and untreated adolescents before, during, and after the period of active treatment [40]. Closs et al. [33] evaluated gingival recessions on mandibular anterior teeth in Caucasian adolescents and concluded that gingival recessions occurred in patients after orthodontic therapy, but the extent and severity of this finding were low. In adult patients, the mean difference of gingival recession between the treated adults and the controls was 0.14 mm, which was not clinically relevant [41]. New recessions developed in 10% of the investigated teeth but no change in 85%. Melsen and Allais [42] followed adult patients (Angle Class I or II malocclusion) who were treated with labial proclination of mandibular incisors and non-extraction. No significant increase in the mean gingival recession was observed during treatment. The prevalence of gingival recession greater than 0.1 mm increased from 21% before to 35% after treatment. Vasconcelos et al. [43] found that the prevalence of gingival recessions after orthodontic treatment was 10.4%. Most (8.6%) were classified as Miller CI, and 1.7% were classified as Miller CII. There were no Miller CIII or CIV. In long term, Gebistorf et al. [44] reported that the prevalence of labial gingival recession increased during orthodontic treatment with further increases during 10 to 15  years posttreatment; 98.9% of the orthodontically treated participants had at least 1 labial recession, which was similar to the untreated controls. Orthodontically treated patients were not compromised in the long term compared with those with malocclusion that was untreated for many years. In New Zealand, Thomas et al. [45] evaluated 12-year-old children and the prevalence of gingival recession (1  mm or larger) was in 66–70% of the subjects after 14  years. In treated patients, 6.9% of the teeth exhibited recessions while 7.0% of the teeth in untreated subjects. There was no statistically significant difference between them. Morris et al. [46] evaluated adolescents including all malocclusion (premolar extractions were 60% of the sample). Only 5.8% of teeth exhibited recession at the end of orthodontic treatment (only 0.6% had recession >1 mm). After 16 years follow-up, 41.7% of the teeth showed recession, but the severity was limited (only 7.0% >1 mm). As a conclusion, orthodontic treatment is not a major risk factor for the development of gingival recession. In the systematic review on the effects of orthodontic therapy on periodontal health, Bollen et  al. [47] found that orthodontic treatment was associated with

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0.03  mm of gingival recession and 0.23  mm of increased pocket depth when compared with no treatment. They mentioned that orthodontic therapy has a minimum effect on the periodontal tissues. Another systematic review [48], similarly, concluded that the amount of gingival recession did not increase significantly after treatment with normal occlusion. In contrast, a positive association between the past orthodontic therapy and the development of gingival recessions in orthodontically treated young adults (18–22  years old) doubled in comparison to untreated individuals (22.9% versus 11.4%, respectively) [32]. Moreover, orthodontic treatment tended to have more severe (>3 mm) and more extensive (3 or more recession sites) gingival recessions. Renkema et al. [49] reported that there was a continuous increase in gingival recessions after treatment from 6.6% at the end of treatment to 38% at 5  years post-treatment. Patients under 16  years of age at the end of treatment were less likely to develop gingival recessions than patients over 16 years. The prevalence of gingival recessions steadily increased after orthodontic treatment in older patients. The ability of the periodontium to withstand orthodontic treatment appears to decrease with age. Renkema et al. [50] compared 100 orthodontic subjects and 120 controls in Norwegian Caucasians approximately after 8  years post-orthodontic treatment. At least one recession site in all the teeth presented in 31% of the treated cases and 16.7% of the controls (ratio; 2:1). The odds ratio for orthodontic patients as compared with controls to have recessions was 4.48. The OR for the increase of age/ year to have recessions was 1.53. The mean number of recessions for treated cases was estimated to be 142% higher than for controls. They concluded that orthodontic treatment may be risk factors for the development of labial gingival recessions. Sawan et al. [51] found that non-extraction orthodontic treatment had 1.31 times higher odds of gingival recession (Fig. 3). In terms of mandibular incisors, fewer than 10% of subjects had gingival recession greater than 2  mm after treatment [42]. The prevalence of gingival recessions after orthodontic treatment was 10.4%, and the recession was predominantly found on mandibular central incisors (87% of affected teeth with gingival recession) but of minor prevalence and severity [43]. The mandibular central incisors showed the most recession, with 12.8% exhibiting 1.0 mm at the end of treatment. After 16 years follow-up, it showed almost 53% exhibiting recession, and 10.3% showing >1 mm of recession on mandibular central incisors [46]. At least one mandibular incisor with a recession was found in 13% orthodontically treated cases and 1.7% controls (ratio; 8:1) after 8  years post-­ orthodontic treatment [50]. In orthodontically treated subjects, mandibular incisors seem to be the most vulnerable to the development of gingival recessions. The risk for orthodontic patients to present with labial gingival recession

Management of Skeletal Class II Malocclusion: Historical Challenges and New Opportunities

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a

b

c

d

e

f

Fig. 3  The patient was diagnosed as angle Class II malocclusion with severe crowding on mandible (a–c). The patient rejected tooth extraction and requested clear aligner treatment. During the treatment, gingi-

val manifestation changed thick to thin. Eventually, loss of keratinized gingiva and attachment loss (d, e) occurred prior to completion of leveling and alignment (f)

seemed to increase at 6  years post-treatment (mandibular incisors: odds ratio: 8.81) [48]. However, these findings should be viewed cautiously until more studies of high quality become available. It is important to identify patients at potential risk and consider the possible implications for orthodontic treatment.

and extrusion during the time of treatment. Similarly, the gingival recessions were reduced in all patients after retracting the roots that were positioned outside the alveolar bone [54]. However, the reduction in recession depth did not result in increased width of the keratinized gingiva in most patients. As a conclusion, orthodontic correction of the root toward the center of the alveolar housing consistently improves gingival recessions but not necessary always increases the width of the keratinized gingiva. Kalina et  al. [55] reported that multiple regression analysis confirmed that more tooth proclination was associated with a higher risk for an increase in gingival recession and showed improvement with retroclining mandibular incisors (mean change in inclination of −7.2°). On the other hand, the association between the amount of mandibular incisor proclination and the gingival recession during orthodontic treatment has been controversial. Some studies showed no relationship [36, 46, 56–60] and others did [55, 63–65]. Ruf et al. [36] found that proclining mandibular incisors in adolescents who had Class II malocclusion by 8.9° did not increase the risk of recession. Artun and Grobéty [56] followed the young patients who had Class II malocclusion. The post-treatment inclination of mandibular incisors was 99.1° (the change +9.98°) in the proclined group and 96.2° (+1.67°) in the control group, respectively. Clinical examinations revealed no differences in the amount of recession between the groups and gingival recession that occurred during the period of active treatment was not progressive. Djeu et al. [57] found that the changes of IMPA and L1-NB during the treatment were 5.0° and 0.87 mm in the excessive

I nclination of Mandibular Incisors and its Limitation The etiology of gingival recession is multifactorial, and history of orthodontic treatment can be considered as a part of it. However, orthodontic treatment includes different types of tooth movement, mechanics, treatment modalities, malocclusion, or skeletal discrepancies. In this chapter, we focus on only orthodontic-related factors at the mandibular anterior region, especially the relationships between labiolingual tooth movement, symphysis, and gingival recession. Lingual tooth movement increased labiolingual thickness of the tissue at the facial aspect of the tooth which resulted in coronal migration of the soft tissue margin (Fig.  4) [52]. Dorfman [53] evaluated adolescents who began with minimal keratinized gingiva (−1°, ≤1°), and proclined (>1°) groups. At the 5-year post-treatment, gingival recessions were present in all groups, but the difference was not significant. They concluded that the change of inclination of mandibular incisors during orthodontic treatment did not affect development of labial gingival recessions in this patient group. Yared et  al. [59] concluded that the final IMPA>95° had no statistically significant correlation with gingival recession in the Angle Class I and Class II malocclusion patients (aged from 18 to 33). Morris [46] reported a similar result that there were no statistically significant differences in gingival recession between the subjects with IMPA >95° and 3°) with a retrognathic mandible without extraction. Their thought-provoking finding in this study was the relationship between dehiscences and tooth movement. It demonstrated through the segmented-­ regression analysis that for each 1  mm increase in L1-NB over 0.71  mm, there was a predictable loss of 1.49  mm in alveolar crestal bone height. Similarly, for each 1° increase in IMPA over 3.0°, there was a predictable loss of −0.48 mm in alveolar crestal bone height. In addition, excessive protrusion (L1-NB > 3 mm) and proclination (IMPA > 9°) of mandibular central incisors caused dehiscences, while patients with tooth movement controlled within L1-NB −2.5 = osteoporosis; between −1 and −2.5 suggests osteopenia. Personal/familial history of cancers Physical examination focusing on oral, head, and neck examination (which should include temporomandibular joint [TMJ] and head/neck myofascial assessment) OSA/airway assessment that includes STOP/BANG or Eppworth questionnaire as well as the NOSE and fatigue severity scale to be completed if the patient does NOT have known OSA Details of any current or past continuous/bi-level positive airway pressure (CPAP/BiPAP) device use, or Mandibular/tongue repositioning appliance use

The same form should capture a comprehensive intraoral, dental, periodontal, and pharyngeal exam assessments including: • Mallampati score (I-IV) • Tonsil grade (I-IV) • Hard- and soft-tissue landmark assessments including midface dimensions, facial skeletal relationships, lip length, gingival display, evidence of altered passive or active eruption • Thorough occlusal assessment • Thorough periodontal assessment including plaque control, inflammation indicators such as purulence/bleeding on probing, probing depth, mobility, mucogingival abnormalities, periodontal phenotype and bone morphotype, furcation involvements, and tooth malpositioning • History of orthodontic treatment • A thorough radiographic review of all available images, which should include a full-mouth diagnostic periapical series, panoramic, lateral cephalometric, CBCT, and/or previous MSCT assessments that note any hard-tissue abnormalities due to skeletal, dental, periodontal, periapical/endodontic, or radicular abnormalities. Particular attention should be paid to CBCT airway images, which should include volumetric components.

 irway Assessment and Management A Capabilities The incidence of (newly diagnosed cases of) sleep-disordered breathing (SDB) has been rising dramatically for at least the past two decades. Similarly, SDB and obstructive sleep apnea (syndrome) (OSA[S]) are underdiagnosed and unaddressed entities in both medical and dental arenas. Because these conditions are such common comorbidities, presurgical assessment of the airway has become a critical step prior to undertaking any SFOT procedure.

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SFOT procedures commonly require at least conscious sedation and usually benefit from more advanced anesthesia such as nasal endotracheal intubation and general anesthesia, depending on the scope of surgery. If the clinician is dealing with an individual with a compromised airway, recoverability of the airway in the event of an intraoperative emergency IS PARAMOUNT—so the clinician must assess these variables when treatment planning SFOT as well as other advanced forms of periodontal and/or dentoalveolar surgeries. Aspects of SDB may not be compatible with administration of fentanyl and other narcotics as this can cause airway management problems by suppressing respiratory drive. A useful preoperative screening assessment for potential airway issues is the STOP-BANG questionnaire [103], which Silva et al. (2011) described as being comparatively more sensitive than either the STOP or the Epworth Sleepiness Scale in identifying SDB, and we have found it clinically useful as a preoperative screening tool for potential airway issues [104]. Briefly, the STOP-BANG questionnaire assesses the following items: (a) Snoring: if you snore, is it louder than talking, or through closed doors? (b) Tired: do you feel tired or fatigued during the daytime? (c) Observed: has anyone observed you to stop breathing when you’re asleep? (d) (Blood) Pressure: are you being treated for high blood pressure? (e) BMI: >30–35 kg/m2? (f) Age: are you over 50 years old? (g) Neck: is your neck circumference >40 cm or 20 inches? (h) Gender: are you male? A patient is at elevated risk of OSA if he or she answers yes to ≥3 of these questions. The clinician may refer the patient to a sleep medicine physician for a polysomnogram (PSG) sleep study and a definitive diagnosis. Sleep studies are costly and usually require insurance precertification, or a significant out-of-pocket payment by the patient. They can also vary in accuracy. Alternatively, SDB can be screened via a high-resolution pulse oximeter. A device worn on wrist for full night with a finger probe measuring oxygen saturation and pulse (Fig. 1). The patient is instructed to use the HRPO for 2–3 nights and then return it to dental/medical office for algorithm assessment. • One useful product uses the SatScreen algorithm by Patient Safety Inc. [105]. This device measures oxygen saturation and heart rate—e.g., assess any fluctuations in heart rate with constant saturation, erratic patterns, episodes of desaturation, and provides the clinician with a

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Fig. 1  Example of a high-resolution pulse oximeter in use on a patient

respiratory distress index (RDI) as well as information about the patients baseline saturation drift during sleep, cycling time (%) and their cycling severity index (Figs. 2 and 3) This screening methodology uses the KonicaMinolta 300i (Fig. 1). Autonomic arousals are also measured through the algorithm. Autonomic arousals occur through central pattern generators in the brain and can be defined as sudden, spontaneous increases in heart rate without concomitant desaturations in oxygen percentage. This is an excellent measure to evaluate for upper airway resistance and is marked in patients who are suffering from fatigue. • Other points to consider are evaluations of gastroesophageal reflux disorder or disease (GERD), which has a 25-year published track record of prevalent association with OSA in both children and adults [106–161]. • A worn dentition can be caused by GERD, bruxism, or a combination of the two; the presence of either/both can be indicative of a potential airway issue.

 edication History and Potential for Drug M Interactions • The surgeon should invest sufficient time in performing a thorough medication history, paying particular attention to potential systemic ramifications associated with SFOT surgery regarding patient’s use of: –– Anticoagulants (history form should capture INR assessment, if the patient is taking warfarin to assess level of control of anti-coagulability). –– Aspirin use, especially in patients taking daily ASA post-MI or for other vascular indications. In such instances, considering a bleeding time test prior to surgery might be a useful planning measure.

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Fig. 2  Demonstration of the SatScreen algorithm by Patient Safety Inc. used for sleep disordered breathing screening. This figure highlights the patients RDI/AHI index, O2 saturation and baseline drift, cycling time, cycling severity and indexes autonomic arousals

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Fig. 2 Continued

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Fig. 3  Demonstrates the patients oxygen saturation coupled with the heart rate during sleep

–– Antihypertensive medications (not uncommon among oral surgery candidates) [23] should be evaluated for in connection with BP assessments, especially on the day of surgery, as well as potential systemic effects of local anesthetic vasoconstrictors on BP. Merli highlights the administration of epinephrine as a vasoconstrictor and provides guidelines for what is generally a substantial margin of safety as long as arrhythmias, unstable angina are not present [23]. –– Oral medications and/or insulin taken for type-2 diabetes –– Insulin type and frequency for type-1 diabetes, presence and type of insulin pump in use –– Psychotropic medications, especially antipsychotics (atypical antipsychotics, e.g., risperidone, paliperidone can impair glycemic control and increase risk of death in older persons with dementia). –– Antiretroviral drugs taken by HIV-infected individuals

• Bisphosphonate use should be evaluated very carefully, especially in relation to any history suggesting bisphosphonate-related osteonecrosis of the jaw (BRONJ) [23]. Evaluate for drug-related, local or systemic risk factors; a position paper by Ruggiero et  al. conveys the American Association of Oral and Maxillofacial Surgeons’ (AAOMS) recommendations for drug-induced ONJ [162]. • There is currently no published literature addressing SFOT in patients receiving bisphosphonates or suffering from BRONJ. Therefore, the clinician must be guided by clinical experience, and general guidelines such as those proposed by Marx et  al, representing AAOMS recommendations regarding oral surgical procedures in patients suffering from or at risk of developing BRONJ; Marx also reviews the increase in the body of knowledge of bone physiology that has arisen from this syndrome [163–165]. However, Abela et al. (2012) reviewed the potential ramifications of bisphosphonate use in regard to its impact on orthodontic treatment and provides guidance [166]. In

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•

•

•

•

general, the use of bisphosphonates is a general contraindication to extensive SFOT surgery in the author’s opinion. BRONJ risk assessment: Recommendations for oral surgical procedures in such patients focus on assessment of serum C-telopeptide prior to surgery [167–170]. Importantly, Hutcheson et  al. conducted a prospective controlled study to evaluate BRONJ risk, based on existing parameters, and found that osteoporosis patients receiving bisphosphonates who had a C-telopeptide (CTX) lower than 150 pg/mL showed sensitivity and an association with an approximately threefold greater risk of developing BRONJ after extractions [167]. –– The clinician may wish to assess CTX when evaluating a patient with osteopenia or osteoporosis for SFOT surgery. If it is lower than 150 pg/mL, surgery should be postponed. –– A thorough oral examination for exposed bone should be performed in patients at risk of BRONJ, and those showing exposed bone and other signs of BRONJ should be managed with chlorhexidine rinses and broad-spectrum antibiotics [23]. The surgeon should be mindful of a specific intraoperative scenario associated with each of the above medications and what they are administered for. Finally, the surgeon should be aware of the consequences of medication noncompliance and be able to determine this through the medical interview. Kumar (2012–2013) offers dental professionals guidance on medication compliance. A direct and detailed history of the use of any elicit drugs should be conducted. Such use can impact surgical outcomes as well as general anesthesia and sedation safety.

Laboratory Testing of Whole Blood/Serum • If laboratory tests are indicated based on results of the medical interview, the dental clinician should request a complete blood count (CBC) from the patients PCP and rely on basic tests such as a CBC and basic metabolic panel (formerly SMA-7 or Chem 7) or comprehensive metabolic panel (formerly Chem 12, SMA-12, SMA-20) to help assess surgical candidacy [61]. • Surgeons must be familiar with disease patterns represented by out-of-range values on these panels [61] • If a patient shows evidence or a history of a bleeding disorder or is taking an anticoagulant(s), acquiring an INR is advisable to assess the extrinsic-pathway system of coagulation [61]. • In conjunction with prothrombin time (PT) and partial thromboplastin time (PTT) added information can be pro-

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vided in regard to intrinsic-pathway system of coagulation, and can also provide evidence of impaired hepatic function in the form of decreased prothrombin-complex synthesis (useful in cases of known or suspected alcoholism) [61]. These tests can also be useful in estimating blood loss during SFOT surgery, in conjunction with hemodynamic assessments (see blood loss estimation under PRESURGICAL WORKUP below). • Surgeons should have an ongoing relationship with a laboratory that is used consistently for such testing or rely on the patients PCP [61]. • The surgeon should also collaborate with patient’s primary-care physician or other medical colleagues in evaluating, interpreting, and assessing lab results.

 tress and Mental Disorders and Their Bearing S on SFOT Outcomes Stress is recognized as a multifaceted syndrome with not only psychologic but also physiologic implications. Oxidative stress is a broad term applied to how the body responds to physical and chemical stressors at the molecular level. Specifically, oxidative stress has been demonstrated to contribute to periodontitis, as measured by biomarkers in saliva [171–175] and urine [176]. A recent study by Hendek et  al. (2014) observed significant reductions in 8-hydroxydeoxyguanosine (8-OHdG) levels in gingival crevicular fluid (GCF) and saliva of patients with chronic periodontitis after initial periodontal therapy was performed, offering evidence that initial therapy may reduce oxidative stress [172]. This underscores the importance of this first step in periodontal management, especially in preparation for surgery. This study corroborates findings by Dede et al. (2013) who first reported this biomarker in GCF and observed a significant correlation between 8-OHdG levels and clinical periodontal measurements [177]. Oxidative stress in periodontitis has been assessed by evaluating biomarkers in additional recent studies, including one by Miriescu et al, who observed significant positive correlations between salivary C-terminal telopeptide of type-I collagen, matrix metalloproteinases-8, osteocalcin, and 25-hydroxy vitamin D3, which are biomarkers of alveolar bone loss, with clinical parameters of periodontal disease [171]. From the standpoint of metabolic disease and cellular oxidative stress, another recent study by Barnes et al. identified biomarkers indicative of unique metabolic signatures in connection with periodontal disease in diabetics [178]. Such metabolic typing could offer a greater degree of personalization (and perhaps efficacy) in periodontal treatment modalities and planning in association with preexisting disease states.

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Presurgical salivary biomarker diagnostics could also provide the clinician with useful information regarding these parameters’ bearing on surgical outcome.

 sychological Appraisal as a Component P of Medical History/Presurgical Testing Mental illness is prevalent and affects approximately 19% of the population of the United States. In 2012, an estimated 43.7 million adults (aged 18 or older) had some form of mental illness. This represented 18.6% of all U.S. adults [179]. Awareness of these statistics is pivotal for the clinician, as is the awareness that emotional components are among the strongest influencers of patient behavior. This underscores the fact that the surgeon and patient must find an emotional connection or “bridge” between the patient’s thoughts and expectations and what is scientifically and clinically possible with the SFOT treatment being contemplated. It is important for the surgeon to review with the patient any mental disorders currently being treated or treated in the past. In particular, the surgeon should be able to assess from the medical interview what the patient’s expectations will be at the outset of treatment, and what potential bearing the patient’s mindset will have on the SFOT treatment outcome. Merli summarizes a classification that groups patients into 4 basic categories: rational, demanding, neurotic, and indifferent, based primarily upon progressively decreasing levels of satisfaction with previous dental treatment [23]. Categorizing this status should provide the surgeon with some predictive value as to whether or not SFOT will provide desired improvements in esthetics and function, preserve existing oral structures, minimize risk, and maximize overall SFOT outcome. Thus, in addition to reviewing the patient’s mental health history and associated medications (or what might emerge as a need for them), the surgeon should assess the patient’s overall level of satisfaction with his or her past dental treatment overall. Self-perception has demonstrated relevance from a number of perspectives in relation to reporting of oral health status and behaviors; notably, self-liking and perfectionism were identified as psychosocial risk markers for such reporting among dental students [180]. The same group of authors found that procrastination and proactive coping had a bearing on perceived oral health and self-reported oral health behaviors [181]. Psychological attachment patterns have also been observed to influence health behavior, treatment utilization, and periodontal variables among 310 compliant patients with chronic or aggressive periodontitis; patterns varied according to gender, disease severity, and early or late treatment-seeking [182]. Hence, awareness of psychological dynamics among patients interacting with periodontal treatment can be of value to the clinician/surgeon.

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Presumably, a patient seeking SFOT treatment possesses a high level of motivation and has an emotional attachment to a good outcome and what will be required to achieve it. However, the clinician must interpret the patient’s emotional state and perceptions carefully to verify this before commencing SFOT treatment. Importantly, anxiety in regard to dental treatment in general is prevalent. Anxiety in regard to periodontal therapy has been studied in regard to pain perception associated with nonsurgical treatment [183], presurgical [184], and postsurgical time points. Anxiety has also been correlated (via Corah’s Dental Anxiety Scale) with level of difficulty experienced during a dental procedure [185]. Most study results suggested greater anxiety and pain perception levels among women than men [183, 186, 187]. Administration of a dental anxiety assessment as part of the medical history interview could provide clinicians with insight into managing pre- and postoperative discomfort. Corah’s DAS and its modifications, in addition to the Dental Fear Survey, are the most commonly used assessments.

Summary and Diagnosis Finally, the history form should include a summary diagnosis section that assists the clinician in focusing on and synthesizing analyses of all available systemic, skeletal/ craniomandibular, periodontal, occlusal, physical, radiographic and patient-reported data, to arrive at diagnoses comprising all head, neck, facial, dental, periodontal, and musculoskeletal/myofascial systems, to arrive at treatment recommendations, and an assessment of how well these recommendations and the diagnostic data underlying them support a treatment plan that includes SFOT.

Presurgical Workup. Putting It All Together After a thorough medical, dental, and periodontal history has been taken and thoroughly reviewed with the patient, the prognosis of tooth movement, space appropriation, and harmonization of arch forms/occlusion through SFOT has been confirmed as good, and all of the potential risks have been explained to the patient and he or she has been afforded the opportunity to have any questions answered, and has given written informed consent, the clinician should focus on the established diagnostic elements with specific operational bearing on the procedure that is planned. Some treatment planning considerations include: • Soft-tissue esthetic considerations including a presurgical assessment of how dentofacial characteristics will impact the overall SFOT outcome. Staging of therapy should be

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considered so that periodontal soft-tissue procedures can be done at the most advantageous time. –– If the presence of mucogingival deficiencies (less than 2mm of attached gingiva present) or where there is lack of keratinized tissue altogether, the clinician may consider mucogingival surgery first, especially if the periodontal architecture is such that soft-tissue thickness is limited and of poor quality (i.e., mucosa). Figures  4, 5, 6, 7, 8, 9, 10, and 11 demonstrate a case where mucogingival therapy was required prior to SFOT surgery. –– Embellishment, reconstruction, or augmentation of the soft tissue may be indicated to harmonize esthetics prior to SFOT (which certainly may precede orthognathics) (Figs.  4, 5, 6, 7, 8, 9, 10, and 11). For mucogingival development, the clinician may opt for an interpositional soft-tissue graft, which could make use of acellular dermal matrix (ADM). As an example, a case report by Park and Wang successfully used an ADM as a barrier membrane to repair a buccal dehiscence defect with mineralized cancellous and cortical bone grafts [188]. –– Improved results have also been reported with pediculated autogenous grafts for sites where implants are being considered or in pontic site development. These techniques can be used in conjunction with SFOT surgery for soft-tissue augmentation at the edentulous site, if appropriate [189]. –– Fagan et al. reported efficacious use of interpositional grafts for ridge and mucogingival augmentation in a 37-case report in the anterior maxilla (interpositional vascularized augmentation neogenesis [IVAN] tech-

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Fig. 5  Lateral view showing the movement of the mandibular anterior teeth out of the bone housing. Periodontal probe is placed at the interproximal bone and shows the relationship of the interproximal bone and projection of the teeth out of bone

Fig. 6  Split thickness dissection at recipient site

Fig. 4  An advanced recession defect and mucogingival defects through the mandibular anterior sextant. Mandibular anterior teeth are being moved out of the orthodontic envelope of bone causing advanced recession at #24 and high vulnerability at remaining teeth for future recession-based attachment loss

Fig. 7  Donor site harvesting of the autogenous connective tissue graft. Single incision technique is used, and good quality connective tissue is appreciated

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Fig. 8  Autogenous connective tissue graft in place and enhanced with enamel matrix derivative protein (EMD)

Fig. 9  Closure of palatal donor site. Primary wound closure has been obtained for uneventful postsurgical course

Fig. 10  Closure of mucogingival surgery pre-SFOT

G. A. Mandelaris

Fig. 11  Three-month root coverage result. Surgical field for SFOT is now more conducive for corticotomy surgery and particulate bone grafting to augment the orthodontic walls.

nique) [190]; while this study was for implant site development, some of the procedures involved were similar to those of SFOT related augmentation. • Pharyngeal/airway assessment in anticipation of general anesthesia/endotracheal tube (ET) placement is critical and should be performed by—or at least in consultation with—an anesthesiologist/dental anesthesiologist. This pre-anesthesia workup should include: –– Assessment of Mallampati Class score (I-IV)—a scale used to assess difficulty of endotracheal intubation. When considering in conscious sedation, a Mallampati I or II classified patient can be sedated safely in-office. Mallampati III and IV should not be sedated in-office as securing an airway could be difficult in absence of ET tube or skilled support to intubate a patient should the need arise. Such cases should be considered to be treated in an outpatient surgical center or hospital operating room where advanced airway management and support is readily available. –– Obese patients may have higher Mallampati Class scores, and radiographic [191] or ultrasonographic assessments [192] can be useful in predicting difficult laryngoscopies or intubations. In particular, a study by Adhikari et  al. described ultrasound imaging at the level of the hyoid bone and thyrohyoid membrane to be predictive of level of level of difficulty of laryngoscopy, and was found not to correlate with commonly used clinical assessments [192]. • The potential blood loss for SFOT surgery should be estimated as part of the presurgical workup, in addition to its

SFOT Surgery

•

•

•

•

potential to affect the hemodynamic stability of the patient. In general, the average blood loss for periodontal surgery ranges from 30 to 200 mL. If the expected blood loss is less than 500 mL, it is categorized as Class 1–2. In this case, a complete blood count (CBC) and basic metabolic panel (BMP; formerly SMA-7 or Chem 7), electrocardiogram (ECG), may be needed (see “cardiology assessment” under “…systemic health” above). Selected Class 3 cases may also be suitable for office-based surgery, provided the foregoing results are all within normal limits, and appropriate clearance from the patient’s PCP and, if necessary, cardiologist, has been obtained. If not, then the procedure should be performed in an ambulatory surgical facility or hospital OR. Anesthesia assessments by the operating clinician and/or dental anesthesiologist should include auscultation of lungs and heart prior to sedation/anesthesia. Assessing a patient’s functional capacity to manage surgery and having guidelines to determine safety is an important part of the presurgical workup. –– Functional capacity assessment using the Metabolic Equivalents for Task Scale (METs) should be considered in patients with potential cardiac issues. Originally defined by Jetté in 1990, MET is a function of the measure of the amount of oxygen consumed at rest, usually expressed in units over time, as a baseline for assessing functional capacity in exercise parameters [193]. –– Typically, 1 MET (energy consumed at rest) is equivalent to 3.5–7 kcal/min. Functional capacity assessment has been examined in a systematic review of by Lemanu et al. [194] that assessed studies on the effect of preoperative physical conditioning on functional capacity (and failed to identify a clear benefit, mostly due to lack of high-quality published data). A review by Rodrigues et al. also provides guidance parameters for functional capacity assessment for cardiac-compromised patients undergoing noncardiac surgery [195]. An evaluation by Xu-Cai et  al. identified no increased mortality rate among patients with stable heart failure who underwent noncardiac surgery [196]. –– Guidelines from the Cleveland Clinic by Whinney provide a useful preoperative checklist for patients at risk for cardiac complications at various levels of screening [197]. –– A MET capacity of 4 or better in a patient without cardiac disease indicates that the patient is a good candidate for surgery. If the MET activity level is 4, and the patient has a history of cardiac disease, then the clinician should obtain a consult with a cardiologist to optimize the patient for surgery. Having a qualified dental anesthesiologist as a member of the interdisciplinary team optimizes the use of all presurgical assessments. In collaboration with the operating cli-

371

nician, additional steps addressed by the anesthesiologist in the presurgical workup should include: –– Obtaining body temperature before surgery should be included with vitals –– Use of algorithms and checklists available for ambulatory surgery [198–204] –– Preoperative assessment of neck circumference and mobility –– Preoperative and perioperative assessment of airway in patients with OSA. Adesanya et al. (2010) have proposed a perioperative algorithm specifically for such patients [199]. –– Consider preparing the skin for venipuncture with chlorhexidine instead of isopropyl alcohol because of the time required for disinfection and to prevent thrombophlebitis. Chlorhexidine has a disinfectant quality after a 1-min application to the skin. Finally, personalized treatment planning should include patient preferences as to management of anxiety, comfort level as well as safety, and to maximize the surgical result in a disease-free environment, both systemically and periodontally. Clinical practice has demonstrated that nutritional supplementation and homeopathic support can be helpful in minimizing discomfort. In addition: • There is published evidence that bromelain (pineapple extract) also possesses activity against a number of periodontal pathogens including Porphyromonas gingivalis [205]. Bromelain (and other hydrolytic enzymes) has also been observed to have positive effects on proinflammatory cytokines such as interleukin-6 [206] and interferon-γ [207], and has demonstrated activity in reducing inflammation after oral surgical procedures [208]. Commercial bromelain formulations can be purchased over the counter in pharmacies, health-food stores, or online. • In addition, the homeopathic remedy Arnica montana has demonstrated anti-inflammatory efficacy in cellulitis of the hand (Arnica patch decreased inflammation) [209], as well as in the postsurgical setting; cumulative evidence of this has recently (2014) been reviewed by Iannitti et al. [210]. Recommendations are as follows if such homeopathic regimens are to be included for surgery: –– Prescribe bromelain to be taken 1–2  days prior to SFOT surgery; clinical practice observed evidence shows that this reduces postoperative inflammation, swelling, and ecchymosis. –– Prescribe Arnica montana to be taken 2  days postoperatively. –– Prior to administration, assess potential allergies to extracts given in these remedies. • NSAIDs should be prescribed for inflammation and pain management post-SFOT surgery, such as Motrin/Ibuprofen. In the authors clinical practice, 600mg Motrin is combined with 625mg Acetaminophen q4–6 h for 7, and his overall ASA physical status classification was ASA II. Medications include Diovan HCT, Norvasc, and simvastatin. Figures 48 and 49 demonstrate the salivary diagnostic data prior to treatment. The data show that the patients overall genetic risk is not a factor of increased risk profile. Interestingly, the bacterial culture shows vir-

tually no microbial pathogens of concern whatsoever. The advanced deterioration of his periodontium circumferentially can be explained by obsessive and traumatic oral hygiene measures over the course of years in addition to having a thin, susceptible periodontium with multiple mucogingival deficiencies. The contributing factor of previous orthodontic therapy is speculative but directory accusatory at the time. The data allowed for the treating doctor to have a meaningful conversation about objective findings in an effort to help elucidate traumatic oral hygiene measures self-imposed by the patient as the primary culprit in the destruction of his periodontium. This was the measure of focus and treatment planning (along with mucogingival therapy) to help stabilize attachment levels and maintain attachment levels.

Result: POSITIVE - 3 PATHOGENIC BACTERIA REPORTED ABOVE THRESHOLD Bacterial Risk: HIGH - Very strong evidence of increased risk for attachment loss Legend = Pathogen Load Threshold* DL = Dectection Limit

Aa

Moderate Risk Pathogens

Low Risk Pathogens

107

107

107

106

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5

10

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DL

5

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Tf

Cs

Result Interpretation: Periodontal disease is caused by specific, or groups of specific bacteria. Threshold levels represent the concentration above which patients are generally at increased risk for attachment loss. Bacterial levels should be considered collectively and in context with clinical signs and other risk factors.

High Risk Pathogens

Aa

Pi

Td

Pathogen

DL En

Result

Fn

Pi

Cr

Pm

Ec

Cs

Clinical Significance

Aa

Aggregatibacter actinomycetemcomitans

High Very strong association with PD: Transmittable, tissue invasive, and pathogenic at relatively low

Pi

Prevotella intermedia

High Strong association with PD: virulent properties similar to Pg; often seen in refracctory disease.

Cs

Capnocytophaga species (gingavalis, ochrace, sputigena)

High Some association with PD: Frequently found in gingivitis. Often found in association with other

Tannerella forsythia

Low

Very strong association with PD: common pathogen associated with refractory periodontitis. Strongly related to increasing pocket depths.

Fn Fusobacterium nucleatum/periadonticum

Low

Strong association with PD: adherence properties to several oral pathogens; often seen in refractory disease

Pm Peptostreptococcus (Micromonas) micros

Low

Moderate association with PD: detected in higher numbers at sites of active disease.

Ec Eikenella corrodens

Low

Moderate association with PD: Found more frequently in active sites of disease; often seen in refractory disease.

Tf

Not Detected:

bacterial counts. Associated with aggressive forms of disease.

periodontal pathogens. May increase temporarily following active therapy.

(Pg) Porphyromonas gingivalis, (Td) Treponema denticola, (En) Eubacterium nodatum, (Cr) Campylobacter rectus

Figs. 40–42  Periodontal inflammation risk and culture results at baseline and one year post treatment demonstrating notable red complex bacteria and microbial biofilm concerns as a part of the diagnostic workup

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Result: POSITIVE - 2 PATHOGENIC BACTERIA REPORTED ABOVE THRESHOLD Bacterial Risk: MODERATE - strong evidence of increased risk for attachments loss Legend = Pathogen Load Threshold* DL = Dectection Limit

Pi

Result Interpretation: Periodontal disease is caused by specific, or groups of specific bacteria. Threshold levels represent the concentration above which patients are generally at increased risk for attachment loss. Bacterial levels should be considered collectively and in context with clinical signs and other risk factors.

High Risk Pathogens

Moderate Risk Pathogens

Low Risk Pathogens

107

107

107

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106

10

10

5

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104

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DL

5

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Pg

Tf

Td

Pm

DL En

Result

Pathogen

Pi

Pm

Fn

Pi

Cr

Pm

Ec

Cs

Clinical Significance

Prevotella intermedia

High Strong association with PD: virulent properties similar to Pg; often seen in refracctory disease.

Peptostreptococcus (Micromonas) micros

High Moderate association with PD: detected in higher numbers at sites of active disease.

Aa Aggregatibacter

Low

Very strong association with PD: Transmittable, tissue invasive, and pathogenic at relatively low bacterial counts. Associated with aggressive forms of disease.

En Eubacterium nodatum

Low

Strong association with PD: specific role uncertain. Often seen in refractory disease.

Ec Eikenella corrodens

Low

Moderate association with PD: Found more frequently in active sites of disease, often seen in refractory disease.

Cs Capnocytophaga species (gingavalis, ochracea, sputigena)

Low

Some association with PD: Frequently found in gingivitis. Often found in association with other periodontal pathogens. May increase temporarily following active therapy.

Result:

NEGATIVE Result:

IL-1A (+4845)

Genotype G / T

IL-1B (+3954)

Genotype C / C

Interpretation:

The results of the PST Test indicate that your patient is NEGATIVE and does not have an increased risk for periodontal disease due to the genetic variations examined in this test.

Figs. 40–42 (continued)

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G. A. Mandelaris

Figs. 43–47  Initial clinical photos of a patient with advanced recession-based attachment loss

Situations such as these call for objective testing methodologies that allow the clinician to better quantify risk, based on the potential presence of specific combinations of virulent (and potentially tissue-invasive) bacteria (i.e., Aggregatibacter actinomycetemcomitans; Peptostreptococcus micros; red complex bacteria [RCB] such as Porphyromonas gingivalis) that may be present in uniquely variable numbers. HPV is a predisposing factor to oral and pharyngeal cancers [383]. Because the incidence of these cancers not sub-

stantially decreasing [385], an early finding of HPV-positive status through salivary diagnostic assessment in a person with a familial history of such cancers or one with an increased risk profile can offer valuable information to both patient and clinician in regard to minimizing other risk factors for such cancers. More stringent examinations and oversight of these higher risk patients, even without the presence of clinical tissue changes or symptomatology, may call for referral to a high-risk head and neck cancer center for peri-

SFOT Surgery

395 Result:

NEGATIVE Result:

IL-1A (+4845)

Genotype G / G

IL-1B (+3954)

Genotype C / C

Interpretation:

The results of the PST Test indicate that your patient is NEGATIVE and does not have an increased risk for periodontal disease due to the genetic variations examined in this test. Result: POSITIVE - 1 PATHOGENIC BACTERIA REPORTED ABOVE THRESHOLD Bacterial Risk: Low - Some evidence of increased risk of attachment loss Legend = Pathogen Load Threshold* DL = Dectection Limit

Cs

Result Interpretation: Periodontal disease is caused by specific, or groups of specific bacteria. Threshold levels represent the concentration above which patients are generally at increased risk for attachment loss. Bacterial levels should be considered collectively and in context with clinical signs and other risk factors.

High Risk Pathogens

Moderate Risk Pathogens

Low Risk Pathogens

107

107

107

10

10

6

106

105

105

105

10

10

104

6

4

DL

DL Aa

Pg

Tf

Td

Pathogen Cs

4

Capnocytophaga species (gingavalis,ochracea,sputigena)

DL En

Fn

Result

Pi

Cr

Pm

Ec

Cs

Clinical Significance

High Strong association with PD: Frequently found in gingvitis. Often found in association with other periodontal pathogens. May increase temporarily following active therapy.

Figs. 48 and 49  Periodontal risk and salivary diagnostic culture results indicating no red complex bacteria in an otherwise non-pocketing periodontitis model

odic evaluation, counseling, and assessment in conjunction with periodic oral examination by the dental professional. This proactive role in early detection and monitoring helps establish the oral health care team on the frontlines in diagnosis and management of these head and neck cancers. After identifying such risks, the initial treatment plan can be geared toward more efficacious management, using aggressive early scaling and root planing, perhaps in combination with oral or local antibiotics, to provide definitive reduction of inflammatory pathogen counts as early in the treatment process as possible, with a view to enhancing surgical results. Questions that can be answered by saliva diagnostic assessments: 1. Is there a risk for greater virulence from potentially tissue-invasive bacteria? 2. Is the patient better placed on antibiotics in conjunction with SRP? 3. Is bone grafting at a therapeutic risk considering the overall treatment plan?

4. Does the microflora profile assessment elevate the risk to adverse healing? 5. Is the patient predisposed to head and neck cancer in the HPV profile obtained and what treatment pathways should be adopted to help ensure long-term survival in these instances? If orthodontic tooth movement is contemplated—especially via SFOT, salivary diagnostics offers valuable data on presence of the most virulent pro-inflammatory bacteria, whose counts can be reduced below threshold levels prior to initiating treatment. Eradicating RCB can help eliminate risk for attachment loss and any degree of periodontitis. Importantly, without bacterial risk assessment, the presence of periodontitis could otherwise be subtle or inconspicuous, and which could sabotage tooth movement contemplated in a well-conceived SFOT treatment plan. In SFOT, tooth movement acquires a higher level of sensitivity to confounding factors. The regional acceleratory phenomenon (RAP) mediated tooth movement process will create an upregulated coupling between osteoclastic and

G. A. Mandelaris

396

osteoblastic activity for a transient period of time (generally 3–4  months). The repositioning of the dentition within a newly created orthodontic wall will be made up of particulate bone graft, which will not have yet completely consolidated or unionized and may be more sensitive to contamination than native host bone in the early phases post surgery. Therefore, reduction of risk in inflammation and bacterial contamination, which creates risks of further attachment loss, becomes especially pivotal in SFOT IDT and underscores the advantages afforded by salivary diagnostics before undertaking such a treatment plan. This allows the clinician to reduce short- and long-term risk from inflammatory, bacterial, and wound-healing standpoints.

Periodontal Inflammation Risk Genetics Assessment of a genotype for interleukin-6 (IL-6) based upon presence of an IL-6 allele (GG) has been identified as a potential risk factor for periodontal inflammation. Evidence for such risk is based on the involvement of IL-6 in the stimulation of osteoclast differentiation factors as well as higher periodontal inflammation risk due to Aa, P. gingivalis and Tannerella forsythia. The presence of the IL-6 allele has also been reported to be associated with systemic risk factors in which inflammation as the common thread. Taken together, such factors may contribute to increased levels of bone resorption and potential associated adverse events during SFOT tooth movement based on its known mechanism of action [384].

Periodontal Inflammation Risk Influencers (a) HPV (b) Family history of oral cancer (c) Patient behavior (smoker or alcohol user) (d) Bacterial profile (e) Periodontal inflammation risk via genotype Quantification of risk can be done by ordering a commercially available testing panel, which assesses bacterial counts, pro-inflammatory cytokine levels, etc. Ability to assess risk at higher levels allows the clinician to educate and build value for the patient. Ordering of such tests can be triggered by sets of clinical findings that suggest increased risk. Inflammation, attachment loss, BOP, and patient-specific risk factors such as age and lifestyle behaviors support the decision to order saliva diagnostic testing. Perhaps most importantly, bone loss in the absence of other signs that overtly suggest overt periodontal inflammation can create a sufficient index of suspicion to seek further information at the salivary biomarker level. Conversely, if a patient has disease limited to gingivitis, crowded teeth, other local factors, and does not exhibit risky behaviors such as tobacco or alcohol use, and has no familial or

HPV-related risk for oral or pharyngeal cancers, the index of suspicion may be much lower and could argue against such testing. An overall objective of compiling data by including salivary diagnostic testing as a part of the workup process is the building of an evidence-based risk assessment model based upon testing in the presence of a variety of risk factors stemming from observations as common as gingivitis and as severe as advanced periodontitis, with an attempt to quantify as yet unidentified variety of disease—and associated risk— in between these extremes. Slight risks such as gingivitis may presage tissue-invasive bacteria, whose risk could be magnified in the presence of aggressive treatment such as SFOT. Furthermore, visual information (such as the printed results of a laboratory panel) can be a powerful motivator for patient education. This also enables the patient to be accountable and responsible for assuming a collaborative role in his or her periodontal health, based on higher levels of clinical information imparted by the educating clinician. This could be a pivotal vehicle for patient empowerment and in motivating patient behavior for the long-term benefit of sustainable oral health, especially when the patients risk profile is high.

 bjectives of Salivary Diagnostic O Assessment 1. Objective assessment of subgingival microflora, and association with increased or decreased risk. 2. Caption SFOT surgery as a significant life event underscoring that significant rehabilitation, reconstruction, and/or regeneration will be taking place. 3. Profiling as to its effect on surgical decision-making and timing of the treatment—and is staging needed re: overall health, plaque control, objective analysis of microflora—juxtapose lower risk with maximum/optimal outcome 4. Helps to position SFOT treatment planning as an extensive, involved approach by an interdisciplinary team, calling for a high level of experience for all practitioners involved. 5. Surgical outcome: Facilitate good flap approximation and achieve successful early to late phase healing patterns. 6. Surgical outcome: Maximize probability of good bone healing and bone grafting outcomes. 7. Assess efficacy of self-performed plaque control. 8. Modify patient’s dental course from a behavior, occlusal, dentofacial esthetic standpoint. 9. Gather data, then discuss with the team…Periodontics, prosthodontics, endodontics, orthodontics, restorative and esthetic dentistry, endodontics, and oral/maxillofacial surgery depending on complexity of the patients’ needs. Frequently, team treatment planning may only involve perio/ortho related requirements with reduced

SFOT Surgery

dental needs and thus reduced involvement of prosthodontics and restorative dental practitioners 10. There is always the possibility of modifying the treatment plan based on salivary diagnostic results and their interpretation, which results from discussion among members of the interdisciplinary team. Risk assessment can be done on an ongoing basis, which would be necessary in any case in order to collect enough data to present significant risk association with salivary diagnostic results, and in the process build an evidence base. Running a baseline panel, then follow-up panels, and the results could form the basis for a good interdisciplinary treatment plan, and ultimately, an evidence-based risk assessment approach for SFOT and other types of periodontal surgery. Such testing does not yet have a strong evidence base and there is nothing close to universal acceptance—and cost can be an issue (approx. $200 per panel). Therefore, geneticists might make a strong argument against the validity of salivary diagnostic testing. On the other hand, commencing a highlevel surgical protocol in the presence of suspicion—but not confirmation—of concerning bacteria—in a susceptible host, and then obtaining a suboptimal result, or worse, a treatment failure, could also be frowned upon. Similar to obtaining CBCT imaging, it may be desirable to have too much information as opposed to not enough when embarking on the scale of treatment plan that SFOT involved interdisciplinary care often does. Sometimes, medical standard procedures rely on empirical evidence and argues against gathering information based on a preconception that it would be unlikely to influence treatment decisions; hence, there is no reason to gather the information. Unfortunately, there is no way to know what information has not been obtained, which is the downside of empiric therapy. This is evident with antibiotic treatment of infectious diseases that eschews obtaining culture and sensitivity data. Perhaps, this model is in need of reevaluation? The question becomes: What level of clinical value do most periodontists assign to assessing risk in this manner, and would add to patient-specific data more strongly with which to drive interdisciplinary decision-making within a risk assessment model? In the end, the goal of SFOT IDT is to change a patient’s dental course from a behavioral, occlusal, dentofacial esthetic and functional standpoint. Recognizing that SFOT is a life-changing event encompasses a treatment planning vision that exercises the greatest degree of pro-activeness possible, given the currently available technology.

397

tic testing. Primarily, objective clinical signs such as vertical bony defects, excessive mobility patterns, and situations where significantly compromised root length (i.e., advanced external root resorption with regional anatomy variables) would be contraindications to performing SFOT + periodontal surgery simultaneously. An effective strategy would be thorough initial preparation therapy/scaling and root planing (SRP), to address periodontal issues first, before applying orthodontic forces to the teeth, and avoiding performing corticotomies in the presence of compromised attachment patterns or when definitive periodontal therapy has not been performed. Frequently, mucogingival procedures are combined with corticotomy surgery, particularly in areas where mucogingival deficiencies are present or in situations where flap aberrations occur during surgery (such as iatrogenic dehiscence or perforations). Two examples of high periodontal inflammation risk (IL-6 genotype G/G [Guanine Base-pair sequence association]) are presented below: Example 3: Figures 50, 51, 52, 53, 54, 55, 56, 57, and 58 a 65 y/o male who shows high levels of concerning bacteria such as RBC including P. gingivalis, and very strong evidence of risk of attachment loss. He showed early-tomoderate periodontal disease based on clinical and radiographic signs. This patient responded well to SRP and suggested combined definitive periodontal surgery/ SFOT surgery could be successfully accomplished. Combined osseous surgery and corticotomy assisted SFOT were accomplished under general anesthesia. Orthodontic therapy was terminated due to the patient’s inability to cope with the brackets and archwires after only 3 months and not at the recommendation of the treating doctors. While clinical outcome assessment appears successful from a clinical periodontal status, the occlusal outcome was not achieved due to the patient’s inability to comply with the orthodontic regimen required. At 1-year post

 ow Does Periodontal Inflammation Risk H Affect Surgical Decision-Making? Decision-making in regard to staged versus non-staged surgery for correction of periodontal defects in a patient who also requires SFOT could be influenced by salivary diagnos-

Fig. 50  R lateral view of patient with Class II malocclusion and inflammatory periodontitis

398

G. A. Mandelaris

treatment and with high compliance to periodontal maintenance intervals q3 months, improvement in most patho-

Fig. 51  Anterior retracted view

Fig. 52  Left lateral view of patient with class II malocclusion and inflammatory periodontitis

Fig. 53  Salivary diagnostics including genotype and periodontal inflammation risk

gens is noted with the exception of Pg which is actually increased. The lack of eradication of subgingival pathogens to below threshold levels across the board, and elevation of a red complex pathogen which was previously below threshold levels, demonstrates the complexity the periodontitis disease and underscores the need for tight long-term oversight by the periodontist under these conditions. Example 4. Figures  59, 60, 61, 62, and 63 demonstrate a 24-year-old Caucasian female who presents with a thin dentoalveolar bone phenotype, bleeding on probing (BOP), early-moderate probing depths characterized by clinical inflammatory signs (redness, swelling, possibly pain). Her past medical history is significant for Celiac disease, Marfan’s syndrome, and hypothyroidism. Medication list includes: Cozaar, Synthroid, and Atenolol. She had been previously treated with Invisalign prior to interdisciplinary therapy involving SFOT. As a part of the diagnostic process, salivary diagnostic data was procured for case planning. The periodontal inflammation risk and culture results are presented in Figs. 62 and 63. This data will help influence the selection of targeted antibiotic therapy, if chosen, based on individualized microbial profiling as well as help begin a discussion about long-term periodontitis control and attachment loss risk. While this data may not alter the treatment plan entirely, it does provide objective information that allows for a personalized approach to periodontal therapy to be developed as well as get the patient involved in her treatment by taking responsibility and ownership of the initial periodontal conditions. Once all the data have been collected, the critical step is to review and if necessary reevaluate the treatment plan with input from all members of the interdisciplinary team.

Periodontal Inflammation Risk

HIGH Result:

MyPerioID

Genotype G / G

Interpretation:

This individual’s interleukin 6 genotype (IL6) is G/G. This MyperioID result indicates your patient has a high risk for periodontal inflammation due to the genetic variation examined in this test.

SFOT Surgery

399

Result: POSITIVE - 2 PATHOGENIC BACTERIA REPORTED ABOVE THRESHOLD Bacterial Risk: HIGH - Very strong evidence of increased risk for attachment loss Legend = Pathogen Load Threshold* DL = Dectection Limit

Ti

Result Interpretation: Periodontal disease is caused by specific, or groups of specific bacteria. Threshold levels represent the concentration above which patients are generally at increased risk for attachment loss. Bacterial levels should be considered collectively and in context with clinical signs and other risk factors.

High Risk Pathogens

Moderate Risk Pathogens

Low Risk Pathogens

107

107

107

106

106

106

10

10

5

105

104

104

104

DL

DL

5

Aa

Pg

Tf

Td

Pathogen Tf

Pm

DL En

Fn

Result

Pi

Cr

Pm

Ec

Cs

Clinical Significance

Tannerella forsythia

High Very strong association with PD: common pathogen associated with refractory periodontitis.

Peptostreptococcus (Micromonas) micros

High Moderate association with PD: detected in higher numbers ar sites of active disease.

Strongly related to increasing pocket depths. Pm

Aa Aggregatibacter antinomycetemcomitans

Low

Very strong association with PD: Transmittable, tissue invasive, and pathogenic at relatively low bacterial counts. Associated with aggressive forms of disease.

Pg Porphyromonas gingivalis

Low

Very strong association with PD: Transmittable, tissue invasive, and pathogenic at relatively low bacterial counts. Associated with aggressive forms of disease.

En Eubacterium nodatum

Low

Strong association with PD: specific role uncertain. Often seen in refractory disease.

Pi

Low

Strong association with PD: virulent properties similar to Pg; often seen in refractory disease.

Cr Campylobacter rectus

Low

Moderate association with development of PD: usually found in combination with other suspected pathogens in refractory disease.

Ec Eikenella corrodens

Low Moderate association with PD: Found more frequently in active sites of disease; often seen in

Cs Capnocytophaga species (gingavalis, ochracea, sputigena)

Low Some association with PD: Frequently found in gingivitis. Often found in association with other

Prevotella intermedia

Not Detected:

refractory disease. periodontal pathogens. May increase temporarily following active therapy.

(Td) Treponema denticola, (Fn) Fusobacterium nucleatum/periodonticum

Fig. 54  Salivary diagnostic data including pre-treatment pathogenic bacteria and threshold levels

Fig. 55  R lateral view post treatment after SFOT/osseous surgery and 3 months of post-SFOT orthodontia.

Fig. 56  Anterior retracted view post treatment after SFOT/osseous surgery and 3 months of post-SFOT orthodontia

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G. A. Mandelaris

Fig. 57  L lateral view post treatment after SFOT/osseous surgery and 3 months of post-SFOT orthodontia

Result: POSITIVE - 4 PATHOGENIC BACTERIA REPORTED ABOVE THRESHOLD Bacterial Risk: HIGH - Very strong evidence of increased risk for attachment loss Legend = Pathogen Load Threshold* DL = Dectection Limit

Pg

Result Interpretation: Periodontal disease is caused by specific, or groups of specific bacteria. Threshold levels represent the concentration above which patients are generally at increased risk for attachment loss. Bacterial levels should be considered collectively and in context with clinical signs and other risk factors.

High Risk Pathogens

Moderate Risk Pathogens

Low Risk Pathogens

107

107

107

10

10

106

10

5

10

105

104

104

104

6

6

5

DL

DL Aa

Pg

Tf

En Pm Cs

Td

Pathogen

DL En

Fn

Result

Pi

Cr

Pm

Ec

Cs

Clinical Significance

Pg

Porphyromonas gingivalis

High Very strong association with PD: Transmittable, tissue invasive, and pathogenic at relatively low

En

Eubacterium nodatum

High Strong association with PD: specific role uncertain. Often seen in refractory disease.

Pm

Peptostreptococcus (Micromonas) micros

High Moderate association with PD: detected in higher numbers at sites of active disease.

Cs

Capnocytophaga species (gingavalis, ochracea, sputigena)

High Some association with PD: Frequently found in gingvitis. Often found in association with other

Tannerella forsythia

Low

Very strong association with PD: common pathogen associated with refractory periodontitis. Strongly related to increasing pocket depths.

Fn Fusobacterium nucleatum/periodonticum

Low

Very strong association with PD: adherence properties to several oral pathogens; often seen in refractorydisease.

Pi

Low

Strong association with PD: virulent properties similar to Pg; often seen in refractory disease.

Cr Campylobacter rectus

Low

Moderate association with development of PD: usually found in combination with other suspected pathogens in refractory disease.

Ec Eikenella corrodens

Low Moderate association with PD: Found more frequently in active sites of disease; often seen in

Tf

Prevotella intermedia

Not Detected:

bacterial counts. Associated with aggressive forms of disease.

periodontal pathogens. May increase temporarily following active therapy.

refractory disease.

(Aa) Aggregatibacter actinomycetemcomitans, (Td) Treponema denticola

Fig. 58  Post treatment salivary diagnostic follow-up data including pathogenic bacteria and threshold levels

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Fig. 59  R lateral view of 24  year old Caucasian female previously treated with invisalign prior to interdisciplinary therapy involving SFOT. Note thin phenotype

Fig. 60  Retracted anterior view of 24 year old Caucasian female previously treated with invisalign prior to interdisciplinary therapy involving SFOT. Note thin phenotype

Fig. 61  L lateral view of 24 year old Caucasian female previously treated with invisalign prior to interdisciplinary therapy involving SFOT. Note thin phenotype

Fig. 62  Salivary diagnostics including genotype and periodontal inflammation risk

Periodontal Inflammation Risk

HIGH Result:

MyPerioID

Genotype G / G

Interpretation:

This individual’s interleukin 6 genotype (IL6) is G/G. This MyperioID result indicates your patient has a high risk for periodontal inflammation due to the genetic variation examined in this test.

402

G. A. Mandelaris

Result: POSITIVE - 2 PATHOGENIC BACTERIA REPORTED ABOVE THRESHOLD Bacterial Risk: MODEARATE - Moderate evidence of increased risk for attachment loss Legend = Pathogen Load Threshold* DL = Dectection Limit

Pm Cs

Result Interpretation: Periodontal disease is caused by specific, or groups of specific bacteria. Threshold levels represent the concentration above which patients are generally at increased risk for attachment loss. Bacterial levels should be considered collectively and in context with clinical signs and other risk factors.

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Peptostreptococcus (Micromonas) micros

High Moderate association with PD: detected in higher numbers ar sites of active disease.

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Capnocytophaga species (gingavalis, ochracea, sputigena)

High Some association with PD: Frequently found in gingivitis. Often found in association with other periodontal pathogens. May increase temporarily following active therapy.

Aa Aggregatibacter antinomycetemcomitans

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Very strong association with PD: Transmittable, tissue invasive, and pathogenic at relatively low bacterial counts. Associated with aggressive forms of disease.

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Very strong association with PD: common pathogen associated with refractory periodontitis. Strongly related to increasing pocket depths.

Td Treponema denticola

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Very strong association with PD: invasive in cooperation with other bacteria. Usually seen in combination with other bacteria.

En Eubacterium nodatum

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Strong association with PD: specific role uncertain. Often seen in refractory disease.

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Strong association with PD: virulent properties similar to Pg; often seen in refractory disease.

Cr Campylobacter rectus

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Moderate association with development of PD: usually found in combination with other suspected pathogens in refractory disease.

Ec Eikenella corrodens

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Moderate association with PD: Found more frequently in active sites of disease; often seen in refractory disease.

Tannerella forsythia

Prevotella intermedia

Not Detected:

(Pg) Porphyromonas gingivalis, (Fn) Fusobacterium nucleatum/periodonticum

Fig. 63  Salivary diagnostic data including pathogenic bacteria and threshold levels

CBCT and Risk Assessment Characterizing the Orthodontic Walls: Classifying Dentoalveolar Bone Phenotypes Background Proper treatment planning is essential to successful outcomes, particularly with interdisciplinary dentofacial therapy (IDT) cases of skeletally mature patients who require orthodontic tooth movement. As such, pre-treatment assessment of the periodontium is commonly evaluated by clinical measures and conventional two-dimensional radiographic review. In IDT cases, particularly those involving the worn or malposed dentition, positioning teeth for an optimal ante-

rior protected articulation may not be feasible, in part, due to the limitation of available dentoalveolar bone along the entire root surface [386, 387]. Historically, periodontal risk assessment has been made from phenotype classifications which focus on alveolar crestal bone, position, and volume in its relation to gingival anatomy [388–392]. These classifications have attempted to relate alveolar crest anatomy to tooth form. Descriptions such as “high or low crest” or “flat vs. scalloped vs. pronounced scalloped” and “thick or thin” are descriptive terms commonly used. Anatomical descriptions related to tooth form also suggest tooth preparation considerations for planned prosthetic dentistry [392, 393]. Such descriptions have considered the gingival width and/or thickness by the

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ability to visualize a periodontal probe when placed through the gingival sulcus [394]. These determinants were based primarily on clinical evaluation or from human skull observations. Phenotype descriptions have also been applied to peri-implant anatomy with decision-making trees to provide the clinician with guidelines in order to execute therapy so that an esthetic outcome is realized [395, 396]. However, these descriptions do not consider the anatomy at the radicular aspect of the tooth root which, in some circumstances, may suffer adverse iatrogenic sequelae with IDT treatment intervention involving orthodontics such as labial tooth movement and/or root torquing. Of late, cone beam computed tomography (CBCT) analysis has been used to determine facial bone presence or absence as well as its volume [397]. Braut and coworkers evaluated 125 CBCTs in humans. They measured the presence or absence of facial bone at an axial slice 4mm apical to the CEJ of maxillary anterior teeth (termed MP1) as well as at the mid-root position (termed MP2). They reported that in roughly 90% of the 498 teeth evaluated, the facial bone was either thin ( apex

mandibular arches and when optimal anterior protected articulation is to be achieved. Pre-treatment knowledge of dentoalveolar bone thickness along the entire tooth alveolus, especially the radicular zone, coupled with the planned orthodontic tooth movement requirements to meet the esthetic and functional outcome goals of the patient and restorative specialist would help to determine whether the patient was a candidate for conventional therapy or if enhanced orthodontic approaches are indicated in order to prevent gingival and bony problems. Since many cases will present with

limited crestal and/or radicular dentoalveolar facial bone (3 mm was evident using clinical examination, photography and CBCT evaluation. He reported that where gingival recession was >3 mm, all teeth showed prominent facial contours and had associated alveolar bone dehiscence’s suggesting a discrepancy exists in these conditions between tooth size and alveolar bone dimensions. In addition, he proposed a radiographicsupporting bone index (RSBI) and categorized them (A-C) to facilitate evaluation of the dentoalveolar bone supporting the mucogingival complex. The RSBI categories do not, however, separate the crestal from the radicular aspect of the tooth alveolus. The crestal and radicular dentoalveolar zones and associated bone phenotype classification system can be uniquely applied for the skeletally mature IDT patient who requires orthodontic tooth movement. It provides a platform for an objective analysis and discussion related to risks imposed on the periodontium. Furthermore, this classification system helps to delineate the limits of traditional orthodontic tooth movement for both dentoalveolar zones in an effort to minimize the occurrence and severity of iatrogenic sequelae. The dentoalveolar bone phenotype classification concept that we propose not only uniquely differentiates and individualizes crestal from radicular zones but classifies facial

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alveolar thickness at any level within each zone to provide the IDT team an opportunity to better assign pre-treatment risk, particularly when orthodontic tooth movement is involved. The classification proposed is simple, requires CBCT analysis, categorizes labial bone thickness of each zone where tooth movement may have consequences, and helps to assist in expanding IDT opportunities for improved outcomes of more demanding cases. It further supports the team approach concept inherent with IDT involving tooth movement for skeletally mature patients.

Conclusion This article presents a new classification system which individualizes and differentiates the crestal from the radicular dentoalveolar bone complex as well as classifies the thickness of each zone. It is a dentoalveolar bone phenotype classification system that incorporates CBCT imaging as a part of the diagnostic process to help clinicians better assign risk in the IDT treatment planning process when tooth movement is planned, to help reduce gingival and bony complications from orthodontic IDT related therapy, and, ultimately, to help improve IDT outcomes for skeletally mature patients.

CBCT and Risk Assessment  isk Assessment in Orthodontic Tooth R Movement. Using CBCT Imaging to Classify Dentoalveolar Bone Phenotypes, Dentoalveolar Bone Deficiencies, as well as Alveoloskeletal Discrepancies Introduction Imaging of the craniofacial complex is a critical component of the interdisciplinary treatment planning process, and CBCT affords the clinical team a 3D view of the two key components: (1) the dentoalveolar (DA) complex. The DA is defined as the relationship between the alveolus and the tooth root in conjunction with its periodontal attachment apparatus. This complex is usually evaluated for deficiencies that may exist in volume between the available alveolar bone and the size of the tooth root within which it is positioned. The second component is described as the (2) alveoloskeletal (AS) complex. This is defined as the relationship between the den-

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toalveolar complex and the skeletal base. This component is usually described and evaluated in terms of discrepancies that may exist between the two—the static skeletal base (developed embryologically via condensing mesenchyme around the second and third divisions of the trigeminal nerve and influenced by muscle interactions in utero) and the dentoalveolar complex (the available alveolar bone supporting the tooth root, which is developed embryologically from perifollicular mesenchyme and the dental follicle during growth and postpartum) (Figs. 81, 82, 83, and 84). DA deficiencies can often be appreciated clinically by dental crowding, which generally signify deficiencies in the supporting alveolar bone itself. Such discrepancies—usually in bone volume—translate into arch length deficiencies in DA bone volume—specific to the alveolus proper. These aberrations are usually recognized most pivotally as tooth migration which also may result in or by attrition and/or erosion of enamel, and subsequent aberrations in root position and morphology, including resorption (Fig. 85a–c). DA deficiencies may occur separately or in conjunction with alveoloskeletal discrepancies. AS discrepancies require an evaluation that addresses the relationship between alveolar process and skeletal base, including their alignment with each other, in concert with addressing bone volume around the tooth/teeth (Fig. 86a–c) Mismatches may occur in the alignment of alveolus to the skeletal base (AS) and in parallel with the ramifications of

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compromised alveolar bone support (DA). Figures  87a–q demonstrate a case of maxillary hypoplasia and a transposed cuspid-premolar attempting orthodontic correction alone for 4 years prior to periodontal consultation. Clinical images and 2D imaging date do not demonstrate the severity of the problem. CBCT imaging and 3D rendering demonstrate the extensive violation of orthodontic boundary conditions and possibility of iatrogenic tooth loss. Tooth movement simulation in DICOM data rendering software is demonstrated to show the orthodontic decompensation set up. The diagnosis of maxillary hypoplasia and dentoalveolar deficiencies in the CBCT imaging simulation software clearly demonstrate the need for dentoalveolar bone augmentation surgery to accomplish orthodontic goals. Patients who have more severe skeletal malocclusions, such as a high angle Class II dentofacial disharmony malocclusion (often observed in patient’s who present with a dolichocephalic craniofacial form and a vertical growing pattern) may have more severe mismatches comprising both DA and AS components which may create more complicated decompensation movements and skeletal malocclusion management. Such complex malocclusion management should be engineered orthodontically and orthognathically (with attention to planning such movements on the face) while maintaining sufficient alveolar bone support during and after treatment for optimal periodontal and mucogingival health.

Fig. 81  Embryologic basis for dentoalveolar bone and periodontium development. Alveolar bone is developed from dental follicle and peri-follicular mesenchyme.

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Fig. 82  Embryogenesis of the static mandibular skeletal bone

Fig. 83  Early embryogenesis of the craniofacial skeleton

 urgically Facilitated Orthodontic Therapy S (SFOT): A Systems-Focused Approach for Correcting Dentoalveolar Deficiences and Alveoloskeletal Discrepancies SFOT comprises selective alveolar decortication with corticotomy surgery in an effort to create a demineralized bone matrix which facilitates tooth movement. Simultaneously, dentoalveolar augmentation is usually performed with bone grafting applications to expand orthodontic boundary conditions which increases the scope of orthodontic tooth movement opportunities. The end result of any bone augmentation

surgery in SFOT is to create a “functional matrix” through “constructive” surgery where sufficient alveolar bone will support teeth in a planned, but orthodontically displaced from baseline (Fig. 88a–h). This functional matrix outcome from bone augmentation surgery infers that a novel sensory regulatory system has been created within the bone matrix which is important for bone maintenance long term. An established functional matrix between muscle-bone-nerve tissue, which ultimately is under the influence of a plethora of mechanical and biochemical cues, that incorporates a novel sensory regulation system implies that a periosteal-

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Fig. 84  Early appearance of the muscle-nerve unit, and the adjacent cartilage bar in embryologic development

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Fig. 85 (a) Soft tissue drape and profile of a Class II patient with alveoloskeletal discrepancy and prominent chin. (b) Hard tissue anatomy of same patient profile with dental crowding. Note the effect of the dento-

alveolar bone (dehiscenses and fenestrations) as a result of dentoalveolar bone volume deficiencies. (c) The dentoalveolar bone zone outlined in green

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Fig. 86 (a) Class II patient profile with primary mandibular deficiency. (b) Class II patient with mandibular deficiency. (c) Class II patient with alveoloskeletal discrepancy in the mandible. Soft tissue profile. (d) Class II patient with alveoloskeletal discrepancy in the mandible.

Regional anatomy. (e) Class II patient with alveoloskeletal discrepancy in the mandible. Alveoloskeletal zone is outlined in turquoise. Mentalis muscle noted

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Fig. 87 (a) Clinical exam of a 17 year old female who has undergone 4 years of orthodontic therapy to correct malocclusion including a transposed maxillary right cuspid with a maxillary right premolar. Right lateral clinical view. (b) Frontal view. (c) Left lateral view. (d) Maxillary occlusal. (e) Mandibular occlusal. (f) Strained relaxed lip position. (g) Smile. (h) Profile. (i) Profile smiling. (j) Cephalometric headplate. (k) Panorex radiograph. (l) Right lateral 3D CBCT reconstruction image via Suresmile® orthodontic planning software. Image reconstruction in 3D represents patient regional anatomy and tooth position reality at 4 years post conventional orthodontic treatment. (m) Frontal view of 3D CBCT reconstruction image via Suresmile® orthodontic planning software. Image reconstruction in 3D represents patient regional anatomy and tooth position reality at 4 years post conventional orthodontic treatment. (n) Left lateral of 3D CBCT reconstruction image via Suresmile® orthodontic planning software. Image reconstruction in 3D represents patient regional anatomy and tooth position reality at 4 years post conventional orthodontic treatment. (o) Right lateral view of 3D CBCT

reconstruction image via Suresmile® orthodontic planning software. Image demonstrates the planned orthodontic tooth movement simulation desired to decompensate the dentition properly and place teeth in the proper positon for occlusion, airway/oral cavity volume and dentofacial parameters. Patient will require orthognathic surgery following decompensation. (p) Frontal view of 3D CBCT reconstruction image via Suresmile® orthodontic planning software. Image demonstrates the planned orthodontic tooth movement simulation desired to decompensate the dentition properly and place teeth in the proper positon for occlusion, airway/oral cavity volume and dentofacial parameters. Patient will require orthognathic surgery following decompensation. (q) Left lateral view of 3D CBCT reconstruction image via Suresmile® orthodontic planning software. Image demonstrates the planned orthodontic tooth movement simulation desired to decompensate the dentition properly and place teeth in the proper positon for occlusion, airway/oral cavity volume and dentofacial parameters. Patient will require orthognathic surgery following decompensation

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Fig. 87 (continued)

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Fig. 87 (continued)

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Fig. 88 (a) Anatomic illustration of a patient with a Class I malocclusion with dental crowding and dentoalveolar deficiencies evident via fenestrations present. Note the axial slice indicating the level of view that future illustrations will be highlighted from. (b) Axial view of the mandibular left demonstrating dentoalveolar deficiencies on the buccal aspect of teeth. There is insufficient bone volume to allow for expansion orthodontia. (c) Buccal only interdental corticotomies illustrated. Note that corticotomies extend well into the marrow. (d) Buccal and lingual corticotomies illustrated. (e) Particulate bone grafting of the buccal aspect where buccal only corticotomies were placed. Bone grafting is performed to increase the outer circumferential volume which will increase the orthodontic boundary condi-

tions within which teeth can be safely moved. (f) Particulate bone grafting of the buccal aspect where buccal and lingual corticotomies were placed. Bone grafting is performed to increase the outer circumferential volume which will increase the orthodontic boundary conditions within which teeth can be safely moved. (g) Demineralized bone matrix extent where buccal only corticotomies were placed and subsequent buccal particulate bone grafting performed. (h) Demineralized bone matrix extent where buccal and lingual corticotomies were placed and subsequent buccal particulate bone grafting performed. (i) Completion of tooth movement and healed bone graft. Demineralized bone matrix secondary to corticotomy surgery has now remineralized. Note the volume of bone achieved for final tooth position

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sharpey fiber endoseum structural continuum is in play, as described by Chin [411, 412]. The convergence for such multifactorial regulation is key (Fig. 89).

 ey Questions for Clinicians in SFOT Treatment K Planning When evaluating treatment planning scenarios that potentially include SFOT, the key questions for the clinical team

Fig. 89  The periosteal-endosteal-sharpey fiber structural continuum

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(especially the orthodontist) from a systemic standpoint include: 1. How, exactly, are the teeth planned to be moved to correct the dentofacial disharmony malocclusion? 2. If arch expansion is planned for decompensation, do consequences of expansive orthodontia (in the presence or absence of SFOT), not only optimally enhance overall

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dentofacial esthetics and smile corridors, make features more distinct and full, but also provide other key outcomes (see rationales 1–5 below) such as an improved incisor angle position and a strong, stable (ideally, cuspid-protected) occlusion? 3. Can the dentoalveolar movements be simulated using 3D CBCT DICOM data so that there is transparency in the orthodontic set up among the treating interdisciplinary team who can contribute to the plan? If not, why ? 4. Does the IDT plan (with or without SFOT) optimize or improve dentoalveolar bone parameters and periodontal health/phenotype, but also optimize oral health conditions which may positively impact systemic health conditions by diagnosing and addressing any potential airway problems (especially in children)? 5. Is the treatment approach affording proper evaluation and management of sleep-disordered breathing conditions and associated measurement variables such as oxygen saturation and heart rate variability? The greater the number of these questions that can be answered affirmatively by all members of the treatment team, the higher the probability that an SFOT treatment plan is not only optimal for oral health conditions, but also can have a positive long-term impact on the chronic diseases of aging, which are multifactorial and affect multiple organ systems, and pose a cumulative effect over time. Pivotally important from both breathing and AS growth standpoints: the earlier an intervention can improve a patient’s airway condition, the greater it can potentially reduce risks more for adverse systemic conditions over time that are linked to impaired breathing and airway compromises that can potentially be averted during the formative phase of craniofacial development. From a DA perspective, SFOT has the potential to reduce risk by putting the teeth in the correct position for dentofacial esthetics, to transform the DA phenotype, and either avoid or remedy deficiencies in DA bone. Such deficiencies are prevalent in the general population, as evidenced by a retrospective radiographic study by Braut et al. [230] that analyzed 125 CBCT scans (498 teeth). They reported that 90% of individuals have thin (less than 1 mm) of facial cortical bone in the crestal area of the maxillary anterior segment. Thick bone was present in only 11.4%. These findings speak to what should be considered anatomically normal, but what is also an epidemiologically widespread deficiency as we understand “normal.” The authors recommend using CBCT to identify thin facial walls prior to extraction [230].

 ive Rationales for Considering SFOT Outcomes F Considerable evidence suggests that SFOT can increase orthodontic stability, improve oral cavity volume, and reduce

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the incidence of orthodontic relapse by corticotomies and bone augmentation surgery used in concert [413, 414]. A 10-year follow-up study by Makki et al. [413] showed significantly lower scores on the mandibular irregularity index (MII, a measure of orthodontic mandibular alignment proposed by Little in 1975 [415]) at both 5 and 10 years after SFOT surgery was performed (which included bone augmentation in addition to corticotomy surgery) compared to conventional orthodontic tooth movement alone. This outcome is likely as a result of (1) severing supracrestal periodontal fibers as a result of the surgery and (2) developing sufficient dentoalveolar bone/improving available arch length of dentoalveolar bone with which to house teeth. These findings suggest that SFOT with augmentation can reduce relapse and can increase long-term stability, a principle that has always been a pivotal—and elusive—overarching goal of orthodontic treatment. According to over 40 years of research by Little et al. at the University of Washington, suboptimal outcomes specific to mandibular anterior crowding, arch width, and arch length after orthodontic treatment pose consistent issues that lack good solutions [416]. In 2006, Rothe et al. evaluated relapse outcomes in post orthodontic patients using cephalometric 2D radiographs. She was trying to determine that relapse was correlated to the trabecular bone pattern and/or cortex thickness. The outcome of her analysis was that thinner mandibular cortices were a predictor for orthodontic relapse [417]. Specifically, the following key treatment rationales for SFOT comprise the following: 1. Position teeth in the correct position for facial esthetics and occlusal function 2. Transform the DA bone phenotype, when necessary, to avoid dentoalveolar deficiencies post orthodontic therapy 3. To reduce the incidence of orthodontic relapse through dentoalveolar surgery. 4. Optimize anterior protected articulation schemes and associated parameters for successful occlusal outcome— cuspid protection disclusion, optimal horizontal and vertical overlap of anterior and posterior teeth, optimal axial inclination of posterior teeth, and incisor angle position of anterior teeth. 5. To optimize oral cavity volume dimensions (A-P and transverse dimensions) and avoid retractive orthodontia or extractions therapy, when possible and appropriate. Historically, dental-specific (i.e., restorative) treatment has centered on managing altered coronal morphology and occlusion through veneers or crowns. In many instances, this requires tooth movement to accomplish but generally doesn’t alter how restorative/prosthetic treatment is performed. Also

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from a historical context, orthodontics has largely been limited to tooth movement within the available alveolar housing and it may enlist orthognathic surgery options to correct malocclusions that cannot be achieved non-surgically to optimize intra-arch or inter-arch relationships. Alteration or augmentation of the dentoalveolar complex was generally never considered until more recently, via SFOT.  SFOT via corticotomies and dentoalveolar decortication plus bone augmentation allows for a demineralized bone matrix to be realized for a short period of time (3–4 months and known as the regional acceleratory phenomena (RAP)). As mentioned earlier, SFOT is usually performed in conjunction with dentoalveolar augmentation where the goal is to develop an augmented and functional matrix outcome. Figure 88a–i provide illustrations that demonstrate these concepts. Table  2 provides the key phases and features of RAP and SFOT. Contemporary interdisciplinary dentofacial therapy (IDT) involving SFOT does not eliminate or devalue orthognathic surgery (OGS), but rather aims to compliment the IDT goals for the skeletal malocclusion who requires OGS.  Table  1 presents five case type patterns of dentofacial disharmony malocclusion and how SFOT may play a role in the management of each [418]. Consideration is now given to the dentoalveolar complex (the most plastic structure of the oral environment when compared to enamel, dentin, or basal bone), in how it can be altered for more predictable tooth movement and augmented for more expansive tooth movement (where conventional tooth limits are far exceeded) but without iatrogenic trauma. Today, the paradigm shift that highlights SFOT within the context of contemporary interdisciplinary treatment planning, the clinical team may choose to modify the dentoalveolar bone complex to allow roots to be placed in the correct position, which may allow for and modification or alteration of coronal morphology to be resurrected or reconstructed using the most minimally invasive—perhaps biomimetic [419–424] or adhesive dentistry-driven treatment approaches possible. Conventional thinking does not focus on the expanded opportunities of dentoalveolar bone alteration but rather focuses on placing the dentition in the best, albeit perhaps compromised, tooth position with conventional orthodontics and then restore the teeth. In many situations, this may be reasonable. However, in many cases where there is advanced attrition and erosion in conjunction with a skeletal malocclusion (often times a Class II), the SFOT approach offers many advantages beyond those gained with the periodontium, especially those with more minimally invasive restorative rehabilitation as inter-arch space has been regained to near optimum to which the teeth can be restored without compromises to form or proportions. It should be noted that many of these alterative applications to conventional therapy have become available because of the use of 3D CBCT imaging and associated software programs that

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simulate treatment opportunities and allow us to study the patient and provide options beyond what is capable with two-dimensional data alone. Reconstructive dental procedures are currently available that help support the pulpal and biologic status of the tooth and generally focus on minimally invasive dental procedures. The overarching restorative objective remains to preserve biologic health and pulpal status of the tooth; more modalities are now available to accomplish this, including CBCT assessment of pulpal morphology [425–430]. In concert with this, the clinical team (beginning with the awareness of the restorative needs of the patient) is well advised to consider airway dimensions as an integral part of a non-retractive orthodontic treatment plan, when feasible. More evidence is accumulating regarding the benefits corticotomy surgery such as to facilitate closure of extraction spaces which may set the patient up for OGS more optimally and timely [431–434]. A key question in the treatment planning process is: What orthodontic treatment scheme is required to manage the malocclusion and can that be accomplished safely to the periodontium. The use of CBCT imaging can best help us analyze this question using a classification system published by Mandelaris et al. (2013) [435]. This classification system categorizes crestal and radicular portions of teeth as thick and thin. Specifically, the crestal region is defined as extending from the CEJ to 4 mm apical to it. The midroot region extends from that point to encompass the rest of the tooth length and classified as thick (≥ 1 mm) and thin (≤1 mm). These dimensions were chosen based on the normative findings of studies published by Braut et al. [230, 436, 437]. Conventional orthodontic and restorative treatments pose risks of DA bone compromise that include bone loss, gingival recession (root exposure) [231], occlusal instabilities [438], and limitations in tooth movements encountered during conventional therapies. A key assessment need for augmentation surgery through SFOT is for the clinical team to determine the potential for providing the patient with a better periodontal outcome posttreatment. This is best achieved by breaking down treatment components into orthodontic, periodontic, and restorative outcome goals, as components of a total treatment consideration set. A number of individual goals to achieve in today’s interdisciplinary treatment environment should encompass: 1. The orthodontic outcome should be compatible with overall biologic health (including effects on periodontium, craniofacial complex, and airway). 2. Long-term stability with no or limited relapse which has long been an enthusiastically sought (but disappointingly elusive [416, 417, 439–441]) 3. Optimal dentofacial esthetics [442, 443]

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4. Avoidance or limitation of extraction therapy (especially premolars, including decreased effect on pharyngeal airway space) [444–447] to produce an end result that projects a broad smile in the transverse dimension 5. An excellent A-P relationship dimension to optimize airway dimensions—no airway constriction or compromise [17] 6. Ideally, the objective should provide the patient with a skeletal and dental Class I occlusion, which may or may not be feasible. Most clinicians seek to foster a good biologic outcome, and a robust DA phenotype should be a consideration. This should comprise favorable DA bone around teeth, with no mucogingival deficiencies (most importantly, preserving at least 2–3 mm of attached gingiva width). Wherever possible, the current periodontal surgical perspective seeks to accomplish a periodontal regeneration result whenever feasible (i.e., PDL, bone, cementum, and Sharpey’s fibers 360° around all teeth), rather that one of a long-junction epithelium, with the dentogingival unit placed at the proper position at each tooth to allow for correct tooth proportion display. Tooth proportions should be set properly, correcting active and passive eruption patterns, so that tooth length is realized, a beautiful smile results, and the patient can keep the entirely of the enamel clean via proper oral hygiene implementation. From an occlusion standpoint, lack of fremitus or occlusal traumatism on the dentition or periodontium should be a sought after goal. From a restorative standpoint: as “quarterback” who will oversee the patient’s oral health for the rest of his or her life, the restorative specialist has the objective of avoiding a worn dentition for the patient, and to maintain the space which has been created through IDT. Often, this can only be achieved by using SFOT to augment the dentoalveolar bone so that aberrant tooth positions are corrected, and restitution of space is achieved without putting the periodontium at risk for adverse consequences. To this end, CBCT scans (taken by any member of the clinical team and shared with others) can be invaluable over the long term in the diagnostic phase.

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Fig. 90 (a) Illustration of a patient with a Class II dentofacial disharmony malocclusion with a long lower face height. (b) Regional anatomy of a Class II dentofacial disharmony malocclusion with a long lower face height. (c) Dentoalveolar zone highlighted in turquoise in

All correct tooth proportions should be restored in the proper craniomandibular dimensions (so as to avoid cyclic fatigue on restorations and teeth). Specifically, a good interincisal-angle relationships and favorable axial inclinations of teeth. Much of this can also be evaluated and verified on CBCT scans after completion of treatment with the patient in a fully seated condylar position.

 lveoloskeletal Phenotype Considerations A In addition to the DA bone phenotypes, CBCT can also be useful in classifying alveoloskeletal dimensions. In the AS relationship, there is a discrepancy between the skeletal base and DA complex that is often influenced by muscle. Patients may present AS configurations in which soft-tissue profile, DA, AS, and skeletal malocclusion problems exist. Figures 85a–86c, 90a–91c illustrate common skeletal phenotype and associated dentofacial disharmony problem renderings. Occlusal Problems Class I skeletal and dental is ideal, and comprises a favorable facial projection, ideal inter-incisal angle relationship, ideal ANB and SNA and SNB angles, Class I molar and cuspid dental relationships with anterior protected articulation, and disclusion patterns (cuspid protection bilaterally is ideal). Figure 92a–c The overall objective is a good facial projection that is supported by favorable skeletal support, generally in a forward pattern. Typically, in a DA compromise or deficiencies, crowding is present. However, the skeletal bases may present in the right A-P relationship, highlighting the problem in the dentoalveolar process. Figure 93a–z demonstrate a patient with a Class I dentofacial disharmony malocclusion with advanced crowding, gingival recession, mucogingival deficiencies in the mandibular arch, and a tooth-arch discrepancy with obvious dentoalveolar deficiencies. Original treatment plan called for a mandibular incisor extraction. However, the patient objected to losing a lower incisor which was not a part of the original treatment plan. A staged SFOT approach c

the mandible and maxilla, skeletal zone outlined in the mandible, and mentalis muscle noted in a patient with a Class II dentofacial disharmony malocclusion with a long lower face height

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Fig. 91 (a) Class III dentofacial disharmony malocclusion patient soft tissue profile. (b) Regional anatomy of a Class III dentofacial disharmony malocclusion patient. (c) Regional anatomy of a Class III dentofacial disharmony malocclusion patient. Dentoalveolar zone noted in

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green, skeletal zones noted in yellow. Zygomatic process included to demonstrate that these skeletal case types often have deficient maxillary processes/zygoma prominence

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Fig. 92 (a) Illustration of patient with a Class I skeletal dentofacial disharmony malocclusion. Soft tissue profile. (b) Regional anatomy of patient with a Class I skeletal dentofacial disharmony malocclusion. (c)

Regional anatomy of patient with a Class I skeletal dentofacial disharmony malocclusion. Dentoalveolar bone, alveoloskeletal and skeletal (all in red) relationships are all in alignment with each other

was presented and accepted to the patient including soft-tissue phenotype conversion and frenum removal in phase I followed by SFOT in the mandible 12  weeks thereafter to augment the dentoalveolar bone complex and expand opportunities for non-retraction/expansion orthodontia. Orthodontic debanding and case completion were accomplished roughly 6 months after SFOT surgery. AS problems are often Cl-II—discrepancies between the skeletal base and the dentoalveolar complex and are influenced by aberrant muscular strain, which influences bone topography. This tends to be a relationship that can be observed in profile—based on the mentolabial fold, chin projection or position, and soft-tissue appearance. In addition, soft-tissue A and B points may be somewhat telling. The Class II skeletal patient may or may not have discrepancy between the DA complex and skeletal base. Depending on the facial growth pattern, more of an effect from muscle pressure may result on underlying bone topography, especially someone with a Class II skeletal pattern exhibiting a long lower face height [411, 412, 448] (Fig. 90a–c). For the Class II patient who has a long face with or without a high mandibular plane angle, it becomes clear that a possible discrepancy exists between DA complex and the AS base, in addition to more impressive muscle tone and, often-

times, short ramus height. So, because the accompanying soft-tissue projection demonstrates the skeletal relationship, and the DA complex is not aligned with the AS base, it manifests as a facial esthetic discrepancy that can be observed from facial and soft-tissue profile (Fig. 90a–c). The Class III AS complex discrepancies usually manifest in the maxilla and in the zygomatic bone which is underdeveloped. These skeletal patterns also tend to manifest under influence of muscle pressure and growth deficiency (Fig. 91a–c).

 imitations of CBCT in Assessment of DA L and AS Phenotypic Details While both DA and AS discrepancies can be evaluated by CBCT scans, greater detail pertaining to an individual’s unique DA phenotype and profile can be better appreciated through CBCT imaging. When examining the aggregate of DA, AS, and skeletal bone condition and position based off imaging alone, determining facial bone can be challenging. Delineation of this critical feature can be obscured by the anterior facial projection of a tooth, and it may not be reliably known where the bone/tooth interface is. In such situations, the clinician should classify this condition as a thin-thin crestal/radicular dentoalveolar bone phenotype.

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Fig. 93 (a) Initial exam of a patient with a Class I dentofacial disharmony malocclusion with severe crowding. Smile. (b) Profile. (c) Right lateral. (d) Frontal. Not mucogingival deficiencies and localized recession as a result of tooth movement exceeding the orthodontic boundary conditions. (e) Left lateral. (f) Mandibular occlusal. Note significant crowding. (g) Maxillary occlusal. (h1) Pre surgical view of mucogingival deficiencies and recession secondary to dentoalveolar deficiencies and dental crowding. Patient is prepped extraoral and intraoral with povidone iodine to decontaminate surfaces prior to surgery. Patient is undergoing phenotype modification therapy, soft tissue, via free gingival grafting #22–27 to set up soft tissue conditions for phenotype modification therapy, bone augmentation, 12  weeks thereafter with SFOT. (h2) Lateral view of clinical situation. Teeth are clearly exceeding orthodontic boundary conditions. (i) Pre surgical radiographs. Two dimensional radiographs, while the current standard of care for mucogingival assessment, do not demonstrate problems related to the bigger picture and that of the regional anatomy/orthodontic boundary conditions. (j) Split thickness dissection, recipient bed preparation #22–27. (k) Free gingival graft sutured to place. (l) Maxillary frenectomy. (m) 8 weeks healing outcome. Note significant change in phenotype conditions and partial root coverage achieved. (n) Full thickness flap reflection and

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corticotomies with dentoalveolar bone decortication. (o) Particulate bone grafting for phenotype modification therapy-bone, as apart of SFOT. Bone grafting is accomplished with corticocancellous mineralized freeze dried bone allograft + xenograft (BioOss). (p) Collagen membrane fixated to place to stabilize bone graft positon. (q) Tension free wound closure using 5-0 monocryl along with 5-0 PTFE suture. (r) 2 week post surgical SFOT outcome. (s) 8 weeks post surgical SFOT outcome. (t) 8 weeks post surgical SFOT outcome. Occlusion view. (u) 6 months post surgical SFOT outcome. Note tooth movement is almost completely finished in an augmented environment whereby no extractions were performed, boundary conditions are augmented and periodontal phenotype is substantially improved. (v) 6 months post surgical SFOT outcome. Anterior close up view. Note substantial anterior volume improvement to allow for completion of tooth movement. (w) 6 months post surgical SFOT outcome. Lateral view. (x) 6 months post surgical SFOT outcome. Broad mandibular occlusal view. (y) Pre surgical cross sectional view of dentoalveolar bone phenotype and orthodontic boundary conditions at initial exam. (z) 6 months post SFOT cross sectional view of dentoalveolar bone phenotype and orthodontic boundary conditions

SFOT Surgery

For interdisciplinary cases, it is important for the clinician to have a comprehensive appreciation of craniofacial morphology, true skeletal classification, and intermaxillary relationship. Importantly, an intensified focus on bone present around existing teeth—more importantly than bone quality— because implants may not be planned. This is especially important in the SFOT treatment planning scenario, in which there is a greater probability that the patient has more of an intact dentition with fewer missing teeth. CBCT imaging can oftentimes be used for dual purposes. Natural drifting or malpositioning of teeth, such as what occurs with dental crowding, is referred to as “dental compensations.” Decompensation is reversing migration and aberrant tooth position, in which the teeth have compensated for a skeletal imbalance (AS or DA bone deficiency or imbalance that manifests as crowding). Grafting is being done to remedy such a compensatory phenomenon in the DA complex, (such as crowding), which will facilitate or enhance orthodontic decompensation, such as correction of occlusion or augment DA bone, to set the stage for the patient achieving the best and most robust periodontal phenotype with the best skeletal base especially if orthognathic surgery is being considered, and in milder skeletal deformities as well. Imaging here makes sure the patient has correct diagnoses from craniofacial, periodontal, DA, and DA bone-risk and bone-volume standpoints. Cephalometric analysis can also be accomplished via CBCT [2, 12, 22, 449–456]. To accomplish this, the patient must be positioned correctly in the scanner, observing a natural head position, and condyles should be seated to evaluate the entirely of the TMJ complex. Generally, the best way to accomplish this is through use of a radiolucent bite registration. Less than 2% of patients in the general population are ideal according to all of the above parameters. In the SFOT treatment planning process, the orthodontist engineers the biomechanics of case, envisioning occlusal, skeletal, and facial outcomes. The envisioned goals include an increase in oral cavity volume, airway dimensions, a facilitation of anterior tongue posturing, and long-term orthodontic stability. Dentoalveolar decortication and particulate bone grafting are performed—usually by the periodontist—to facilitate and expand orthodontic applications in correcting malocclusion and/or restitution of aberrant tooth position. The surface area created by the surgery results in a regional acceleratory phenomenon (RAP) as described by Frost, also known as a transient alveolar osteopenia [218]. Corticotomies done within the cortical bone into medullary bone, buccal and lingual, or in the direction of tooth movement, depending on complexity of case and needs for tooth movement. Corticotomies are made around the tooth root because SFOT is a periodontal ligament-driven phenomenon [215, 217, 384, 401, 402, 457–460] (Fig. 88a–i).

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After decortication and corticotomy, a demineralizationremineralization coupling phenomenon occurs, which reduces mineral content for a short time and allows the orthodontist to move teeth expeditiously and limiting the potential for apical root resorption or other adverse sequelae [215, 217, 384, 401, 402, 457–460]. One of the key implications of such combination treatment is bypass of the lag phase inherent in conventional orthodontic treatment. The coupled demineralization-remineralization phenomenon makes effects occur sooner and affords a reduced risk of hyalinization of the PDL [215, 217, 384, 401, 402, 457–460]. A reversible and transient alveolar osteopenia is incited by corticotomy and decortication [384, 457], without a pathologic risk of loss of alveolar bone mass, density, or volume [215, 217, 401, 402, 458–460]. Using a rat model, Baloul et al. [384] have described specifics of this mechanism of action that underlie alveolar decortication and facilitated tooth movement. In comparison to a tooth-movement-only active control group, they observed accelerated tooth movement in the group that received corticotomy and tooth movement, during the initial displacement phase. This was associated with increased expression of markers of both osteoclastic (including RANKL receptor and osteoprotegerin) and anabolic osteoblastic (including osteopontin and osteocalcin) activities, illustrating the mechanism of the combined resorption/apposition of bone during the initial phase of tooth movement in response to corticotomy [384]. These findings corroborate and expand upon results obtained by Sebaoun et  al. [457], who used a similar rat model (but did not assess tooth movement). They described a similar anabolic/catabolic acceleratory phenomenon in response to selective alveolar decortication injury that occurred within the alveolar spongiosa and lamina dura. Over a 3-week period, they observed a twofold decrease in calcified trabecular spongiosa, a twofold increase in PDL surface area, and threefold increases catabolic and anabolic activity, as evidenced by markers of osteoclastic and osteoblastic activities. This produced significant increases in trabecular tissue turnover by 3  weeks, which stabilized to steady state by 11 weeks. In the rat model, at the end of the RAP period, there is an increase in bone density around the teeth, so the end result of corticotomy is more additive rather than subtractive.

 se of CBCT for Diagnosis and Management U of Periodontal Defects CBCT can also be useful for visualizing intrabony defect morphology and topography, as well as furcation bone levels. However, CBCT tends to overestimate actual bone loss compared to traditional radiographs. Figure 94a–zd demonstrate a case of advanced crowding and malocclusion. An extraction-

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Fig. 94 (a) Initial exam demonstrating a patient with Class I dentofacial disharmony malocclusion and severe dental crowding. Gingival recession and a mucogingival deficiency exist at #24. (b) Mandibular occlusal demonstrating severe crowding. (c) Diagnostic 3D models acquired from CBCT imaging and DICOM rendering via Suresmile® orthodontic software. (d) 3D modeling demonstrating mandibular setup to correct dental crowding if no teeth are extracted. Frontal view. Note the significant dentoalveolar deficiencies and lack of orthodontic boundary conditions to allow for safe tooth movement. (e) 3D modeling demonstrating mandibular setup to correct dental crowding if no teeth are extracted. Lateral view. Note the significant dentoalveolar deficiencies and lack of orthodontic boundary conditions to allow for safe tooth movement. Extent of planned tooth movement exceeds what can be achieved with dentoalveolar bone augmentation surgery predictably. Teeth are taken too far off the skeletal base and exceeds the limit of what can be achieved with periodontal dentoalveolar bone surgery. Case will require extraction-retraction therapy. (f) 3D modeling demonstrating mandibular setup to correct dental crowding with set up where extraction of second premolars are planned. Frontal view. Note the significant dentoalveolar deficiencies and lack of orthodontic boundary conditions to allow for safe tooth movement, but improved from non-extraction case set up. (g) 3D modeling demonstrating mandibular setup to correct dental crowding with extraction retraction case set up. Lateral view. Note the significant dentoalveolar deficiencies and lack of orthodontic boundary conditions to allow for safe tooth movement, but improved from non-extraction case set up. Extent of planned tooth movement is in lined with what can be achieved with dentoalveolar bone augmentation surgery predictably. While case still requires extraction therapy, there is not dentoalveolar bone volume to allow for safe tooth movement. SFOT will be required and is preditable. (h) Phenotype modification therapy, soft tissue via free gingival grafting #24–25, to set up the mandibular arch for SFOT surgery. (i) 12 weeks post op free gingival graft surgery for phenotype modification therapy- soft tissue. Pre op SFOT surgery clinical situation. (j) Mandibular arch full thickness flap reflection. Note that while 3D modeling suggested multiple teeth had dehiscenses (such as #22), actual clinical situation disputes modeling. Facial bone is present and intact,

although minimal (