Functional Aesthetic Dentistry: How to Achieve Predictable Aesthetic Results Using Principles of a Stable Occlusion [1st ed.] 9783030391140, 9783030391157

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Functional Aesthetic Dentistry How to Achieve Predictable Aesthetic Results Using Principles of a Stable Occlusion Neeraj Khanna

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Functional Aesthetic Dentistry

Neeraj Khanna

Functional Aesthetic Dentistry How to Achieve Predictable Aesthetic Results Using Principles of a Stable Occlusion

Neeraj Khanna Khanna Dentistry PC Geneva IL USA

ISBN 978-3-030-39114-0    ISBN 978-3-030-39115-7 (eBook) https://doi.org/10.1007/978-3-030-39115-7 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved 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

Acknowledgments

As you know, this book could not have been a reality without the many people that are a part of my life. I am forever indebted to Dr. Peter Dawson who was responsible for igniting the fire in my belly which has allowed me to pave the path to help so  many dentists along the way. The  incredible team at  the Dawson Academy, including Ms. Joan Forrest, has been very instrumental and supportive of my passion to teach Dr. Peter Dawson’s principles. This book is a compilation of experiences that I have been able to share with you because of so many great patients in my practice. I am honored and humbled that they have entrusted me with something that means so much to them—the health of their entire masticatory system. I thank them for being so incredibly patient and understanding with me throughout all of their treatment procedures. Those patients could not have gone through this process without the help of my dedicated team. My talented team consists of Gina Lazzerini and Taylor Bianchini. Through the years, both Gina and Taylor have witnessed and endured the challenges of transforming a practice from general dentistry to comprehensive, aesthetic, and functional dentistry. They have helped embrace, support, and implement my vision into the practice. Gina has been by my side for over 20 years, and I will always be so grateful for her loyalty, commitment, and dedication to me and my practice. I cannot forget all those patients (especially the ones who have been mentioned in this book) who entrusted me with the responsibility to take care of them throughout the process of treatment. It has been my honor to serve you. My parents, Shiv and Kavita have been my well-wishers since the day I was born. They have always believed in me and have always supported my ambitions and dreams. Their spiritual faith and belief were a reminder that one day this book would be written. I am so blessed and  grateful that they are going to see this book come to fruition. I can remember growing up hearing my father’s well-known quotes of wisdom and inspiration. Later in life, I have come to appreciate them as they have provided me with a deeper understanding of myself and others. My only younger brother Manoj, who has been with me spiritually throughout my personal and professional journey.  He  had seen my life from a different perspective  and watched the  transformations over the years;  I  have so many great memories and moments with him. He has always been my great friend and supporter. Thank you to my entire family. Finally, there is always a great woman behind a successful man. I can boast that I am blessed to have a great woman by my side, who is my wife, Jeanie. Her grace v

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and simplicity of life is a gift that only a few possess. From the moment I was awakened (professionally) by Dr. Peter Dawson, she has been my best supporter and played a significant support role in helping me write this book. She has given me my two children, Raj and Maxime, who have shown me what love, patience, and understanding really mean. I am so blessed to have such beautiful and loving children. Thank you for the incredible support in allowing me to “be what I want to be,” “go where I want to go,” and “write what others will read.” This book could not have been completed without my family’s loving support and encouragement. Please read this book with an open mind. I hope it teaches you the important principles that will help you elevate your understanding of dentistry and, hopefully, allow you to implement this understanding with your patients and team members. Finally at the beginning of each chapter, there will be an example of a quote from my father and a few of my own that are meaningful to me and my life. Below I leave you with the first one that is very appropriate. Enjoy! Live as if you were going to die tomorrow, learn as if you were going to live forever. Mahatma Gandhi

Contents

1 Functional Aesthetics ��������������������������������������������������������������������������������   1 1.1 Anterior Teeth ������������������������������������������������������������������������������������   4 1.1.1 Maxillary Central Incisor��������������������������������������������������������   4 1.1.2 Maxillary Lateral Incisor��������������������������������������������������������   6 1.1.3 Maxillary Canine��������������������������������������������������������������������   7 1.1.4 Mandibular Incisors����������������������������������������������������������������   8 1.1.5 Mandibular Canine������������������������������������������������������������������   9 1.2 Smile Zone������������������������������������������������������������������������������������������  12 1.2.1 Teeth����������������������������������������������������������������������������������������  13 1.2.2 Gingiva������������������������������������������������������������������������������������  16 1.3 Posterior Teeth������������������������������������������������������������������������������������  19 References����������������������������������������������������������������������������������������������������  20 2 Functional Occlusion: Understanding and Thinking ����������������������������  23 2.1 Discussion ������������������������������������������������������������������������������������������  23 2.2 Occlusion��������������������������������������������������������������������������������������������  24 2.3 History������������������������������������������������������������������������������������������������  28 2.4 Temporomandibular Joint ������������������������������������������������������������������  29 2.5 Chewing Cycle������������������������������������������������������������������������������������  31 2.6 Occlusal Disease Classification����������������������������������������������������������  32 References����������������������������������������������������������������������������������������������������  34 3 The Envelope of Function: Understanding and Importance ����������������  35 3.1 Discussion ������������������������������������������������������������������������������������������  35 3.2 Mandibular Movements/Envelope of Motion ������������������������������������  36 3.3 Envelope of Function��������������������������������������������������������������������������  39 3.4 Restricted Envelope of Function��������������������������������������������������������  41 3.5 Verifying Envelope of Function/Technique����������������������������������������  46 References����������������������������������������������������������������������������������������������������  53

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4 The Complete Examination: The 12 Steps Needed to Perform a Complete Exam������������������������������������������������������  55 4.1 Discussion ����������������������������������������������������������������������������������������  55 4.2 New Patient Interview����������������������������������������������������������������������  57 4.2.1 Build Rapport������������������������������������������������������������������������  58 4.2.2 Past Dental Experiences��������������������������������������������������������  58 4.2.3 Inquire About What the Patient Knows About Their Oral Health ������������������������������������������������������  59 4.2.4 Inquire About Patient Expectations��������������������������������������  59 4.2.5 Educate Patient on Normal Dental Health, and Your Philosophy��������������������������������������������������������������  60 4.2.6 Inform Patient on the Expectations of the Examination Co-discovery������������������������������������������  61 4.2.7 Learn Something Personal About Your Patient (Family, Job, Kids, Hobbies)������������������������������������  62 4.3 Patient Office Tour����������������������������������������������������������������������������  62 4.4 TMJ Examination������������������������������������������������������������������������������  63 4.4.1 Joint Palpation����������������������������������������������������������������������  66 4.4.2 Doppler Auscultation������������������������������������������������������������  66 4.4.3 Range/Direction of Motion ��������������������������������������������������  68 4.4.4 Joint Loading������������������������������������������������������������������������  71 4.5 Muscle Palpation������������������������������������������������������������������������������  77 4.6 Occlusion������������������������������������������������������������������������������������������  82 4.7 Oral Cancer Screening����������������������������������������������������������������������  82 4.8 Hard/Soft Tissue�������������������������������������������������������������������������������  83 4.9 Intraoral Images��������������������������������������������������������������������������������  83 4.10 Periodontal Probing��������������������������������������������������������������������������  84 4.11 Appropriate Radiographs������������������������������������������������������������������  85 References����������������������������������������������������������������������������������������������������  87 5 Diagnostic Records: What to Take and Why������������������������������������������  89 5.1 Discussion ������������������������������������������������������������������������������������������  89 5.2 Facebow����������������������������������������������������������������������������������������������  96 5.3 Centric Bite Record���������������������������������������������������������������������������� 100 5.4 Perfect Impressions���������������������������������������������������������������������������� 111 5.5 Digital Photography���������������������������������������������������������������������������� 111 References���������������������������������������������������������������������������������������������������� 123 6 Incisal Edge Position: Its Importance to Aesthetics and Function�������� 125 6.1 Discussion ������������������������������������������������������������������������������������������ 125 6.2 Central Incisor Anatomy Review�������������������������������������������������������� 129 6.3 Incisal Edge Wear ������������������������������������������������������������������������������ 135 6.4 Incisal Edge-Aesthetic Components �������������������������������������������������� 137 6.5 Incisal Edge-Functional Components ������������������������������������������������ 138 6.6 Predictable Incisal Edge Design �������������������������������������������������������� 139 References���������������������������������������������������������������������������������������������������� 142

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7 Phonetics: How to Design with Phonetics in Mind �������������������������������� 143 7.1 Discussion ������������������������������������������������������������������������������������������ 143 7.2 Manner of Articulation������������������������������������������������������������������������ 144 7.3 Place of Articulation �������������������������������������������������������������������������� 145 7.4 Phonetics in Dentistry ������������������������������������������������������������������������ 147 7.5 “F/V” Sounds�������������������������������������������������������������������������������������� 148 7.6 “T/D” Sounds�������������������������������������������������������������������������������������� 148 7.7 “S” Sounds������������������������������������������������������������������������������������������ 149 References���������������������������������������������������������������������������������������������������� 152 8 Diagnosis and Treatment Planning���������������������������������������������������������� 153 8.1 Functional Diagnosis�������������������������������������������������������������������������� 159 8.2 Structural Diagnosis���������������������������������������������������������������������������� 168 8.3 Diagnostic Occlusal Analysis ������������������������������������������������������������ 170 8.3.1 Steps 1 and 2 �������������������������������������������������������������������������� 178 8.3.2 Steps 3 and 4 �������������������������������������������������������������������������� 180 8.3.3 Step 5�������������������������������������������������������������������������������������� 184 8.3.4 Step 6�������������������������������������������������������������������������������������� 185 9 Communication: With Your Patient/Specialists/Technicians���������������� 193 9.1 Discussion ������������������������������������������������������������������������������������������ 193 9.2 Dentist and Patients (Primary Relationship)�������������������������������������� 198 9.2.1 Part 1 �������������������������������������������������������������������������������������� 200 9.2.2 Part 2 �������������������������������������������������������������������������������������� 200 9.2.3 Part 3 �������������������������������������������������������������������������������������� 200 9.3 Dentists and Specialists (Secondary Relationship)���������������������������� 203 9.3.1 Digital Photography���������������������������������������������������������������� 208 9.3.2 Aesthetic Imaging ������������������������������������������������������������������ 209 9.3.3 Aesthetic Periodontal Calculation������������������������������������������ 211 9.3.4 Surgical Stent�������������������������������������������������������������������������� 217 9.4 Dentists and Dental Technicians �������������������������������������������������������� 220 References���������������������������������������������������������������������������������������������������� 227 10 Preparation, Planning, and Quality Control ������������������������������������������ 229 10.1 Strategy: Treatment Planning, Presentation, and Acceptance �������������������������������������������������������������������������������� 231 10.2 Execution: Teeth Preparation, Provisionals, Communication with Dental Labs���������������������������������������������������� 235 10.3 Finish Line: Quality Control, Delivery of Restorations�������������������� 240

Introduction

If you were to tell me at the time of my graduation from the dental school in 1993 that one day I would be writing a book, then I would be telling you that you have lost your mind. That would have been a young graduate from the University of Detroit Mercy School of Dentistry who was inexperienced but was ready to take on the world! The idea of writing a book would have been the furthest thing on my mind. It is safe to say that destiny had other plans. Since graduation from the dental school, my life (professional and private) has taken many turns, including significant events along the way. One of those events will be described in more detail as you continue to read. In hindsight, I truly believe that all the significant events in my life have played a key role that has led me to what I am at this point in time. This book was written with purpose and passion from years of teaching and inspiring so many. This next “chapter” in my life is to write a book about something that I am very personal and passionate about. In March of 2000, I started my own dental practice, and like many of you, my primary goal was to grow, and pay my bills. My patients liked me, my practice became very busy, and I could do no wrong. I was a confident dentist, and I loved the results of my treatment. With the growth that I experienced, I started to hire more staff and began to realize that this is what was expected as a result of being successful. At one point, I also realized that the space that I was occupying was not enough. I would have to consider relocating to a larger space or higher associates to keep up with the demand. Fortunately (I say this in hindsight) in late 2005, I was starting to feel disconnected emotionally and physically from my practice. I no longer enjoyed the practice of dentistry. The novelty of being “busy” had worn off and the clinical frustrations of being a dentist became very apparent. You may relate to this example as this was frustrating me for years: A second molar was being treated for a crown preparation. I reduced at least 1.5 mm from all aspects. I prepared the tooth with ideal reduction (1.5 mm from all sides), and when it came time to confirm the preparation (having the patient close down), I could see there was very little interocclusal space to fabricate a provisional crown. At that point, I further reduced the occlusal preparation to give me space for the provisional crown. The provisional restoration was still very thin, and the final impression was sent to the lab. Upon the cementation appointment, the amount of time spent adjusting the occlusion resulted in the

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entire occlusal anatomy being obliterated. Figure 1 illustrates the same example of a patient whom I saw 2 years ago presenting with the same situation on tooth #18 (or 3.7), except the crown restoration that did not last. This patient experienced the same scenario elsewhere. Figure 2 illustrates the same patient not having adequate interocclusal space, and finally Fig. 3 clearly shows the results and what caused the restoration to come off. Had I seen this patient 13 years ago, I am not sure if I could have understood nor solved this problem. Today, there are many dentists all over the world who are  still experiencing these same issues with preparing restorations on  second molars. The same patient as illustrated in Figures  1–3  has undergone treatment to solve this problem with a different process that involves understanding the occlusion. Today, this same tooth has been restored in a predictable way to respect the patient’s occlusion and function. What was even more startling was the fact that over time I started to see my patient’s clinical results change, especially with anterior restorations. The frustration began to get worse as I was experiencing patients returning for multiple occlusal adjustments, and when my patients asked why, I did not have the clarity to provide them with the answers to the current problem. In 2004, one of my patients (post-treatment completion) continued to present on multiple times to address occlusal issues which required many adjustments to the occlusion. Figure 4 illustrates this patient (smile view). Furthermore, Figures 5, 6, 7, and 8 illustrate the aesthetic results (I cringe when I look at these photos!) and the changes that have taken place over time—perforations, fractured porcelain on cuspid teeth, diastema, and many other issues. Patients like these spend time and money and deserve the very best in dentistry that is predictable and long lasting. Unfortunately, at the time I could not provide the patient with an amazing result. Instead of looking for an external reason, I began to look inward. This was the moment when I began taking the steps in my career to be truly reborn. Perhaps then I realized that just treating teeth was not working in the best interest of my patient nor myself (my mental stress). There had to be something more than just treating teeth. The dental school does not teach enough to solve complex problems or deliver predictable results. The dental school has an obligation to educate students, so they acquire enough intellect and aptitude to complete a board examination that allows them to obtain a professional license. I reached a crossroad in my career where I had to either continue down the same path (which would have ended my career sooner) or choose another one. I chose the latter and had the good fortune of having a team member who was previously employed by a Roth-trained orthodontist who was passionate about occlusion. This team member suggested that I investigate occlusion as a possible solution to my dental frustrations. After some research, I decided to take a class in 2006 and hear Dr. Peter Dawson speak about occlusion. During the first day of class, I experienced an epiphany, a moment where my professional life had been permanently changed. In a lecture room with over 250 people, I truly felt that Dr. Dawson was speaking to me and only

Introduction

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me, and it was loud and clear. I had clarity and a new purpose. I realized two things at that moment. First, I needed to master this process of “complete dentistry” and, as he stated so eloquently, be a “physician of the masticatory system.” Second, I needed to help as many dentists as possible to understand this process of complete dentistry. During a timeline of just over a year, I completed Dr. Dawson’s curriculum and implemented everything into my practice. Fast-forward and today I write this book to share my interpretations and experiences to help you understand the importance of providing your patients with the very best results possible that are predictable and long lasting. I have learned over the years through teaching and speaking that a dentist sometimes can be very critical about another professional work and/or results. This mind-set is what I like to call “the box.” Every dentist lives and breathes in their own professional “box.” They get comfortable and eventually complacent. All that I ask of you is to read this book with an open mind, and hopefully your “box” can be expanded. This book is not meant to be a book of before and after photos, but one that explains the principles of occlusion and how this philosophy can be applied to patients from all walks of life. This philosophy does not discriminate, nor does it assume anything.

Fig. 1  Patient example of second molar crown prep

xiv Fig. 2  Patient example of same second molar preparation and the occlusal relationship to the opposing tooth

Fig. 3  Patient example of existing crown restoration of the same second molar

Introduction

Introduction Fig. 4  Patient example of previous dentistry— Smile view

Fig. 5  Patient example of previous dentistry—Maxillary occlusal view

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xvi Fig. 6  Patient example of previous dentistry— Mandibular occlusal view

Fig. 7  Patient example of previous dentistry— Retracted anterior closed view

Fig. 8  Patient example of previous dentistry— Retracted anterior open view

Introduction

1

Functional Aesthetics

You never fail until you stop trying. Albert Einstein

Contents 1.1  Anterior Teeth 1.2  Smile Zone 1.3  Posterior Teeth References

 4  12  19  20

It is well known that the eyes are the gateway to a person’s soul and a smile is the gateway to a person’s personality. This is true fact as the practice of aesthetic dentistry is documented as far back as 2500 BC [1]. It was not till scientists discovered skulls dating back to the Mayan civilization between 300 and 900 AD where ancient tools (bow drill—see Fig. 1.1) were used to drill holes in the facial surfaces of anterior teeth [2]. These holes were filled with stones like jade and turquoise, see Figs. 1.2 and 1.3. The importance of this ritual simple was based on social status. The evolution of dentistry has transformed from filling holes, to recreating life like restorations. In the 1990s, the US dental industry was in a time of an aesthetic revolution. It was known as the American “Hollywood Smile” which was pure “white” teeth. There were reality TV series with cosmetic dentists creating beautiful smiles. It became cultural norm where patients just wanted “white” teeth. This was a boost in Dentistry as so many patients were seeking aesthetic treatment. I often wonder for the dentists that were jumping on the aesthetic bandwagon, how many aesthetic procedures were completed without seriously taking into consideration the patient’s function and occlusion? Most published articles and advertisements show aesthetic results that only focus on changes in color and shape. For many decades, the concept of

© Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_1

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2 Fig. 1.1  Depiction of Mayan dentist, Circa 750 A.D

Fig. 1.2  Ancient Mayan teeth inlayed with jade, Circa 750 A.D

1  Functional Aesthetics

1  Functional Aesthetics

3

Fig. 1.3  Close up of Mayan teeth inlayed with jade, Circa 750 A.D

aesthetics in dentistry has stayed focused on just these results. From the perspective of the patient, they seek changes in these two areas. There was a time in my practice where I thought I was giving my patient’s the very best aesthetic results. At that time, I was proud of the fact that the results delivered was the best possible and there could be no more improvement needed. However, when I review my past photos, I realized how much I did not know and how much now I appreciate aesthetics now! My expectations were similar to my patients, color, and shape. As long as those two items were achieved, they were pleased and as a result, I was happy too. This process and understanding of “complete dentistry” truly allow the dentist to be in control of the outcome by preplanning the outcome before the tooth preparation begins. However, the perspective from the Dentist must go beyond these two parameters. There is a better way to achieve results that are not only dictated by color and shape. Today, patients who are demanding aesthetic treatment have higher expectations and are now asking for natural appearing smiles. This can include not only color and shape but also characteristics such as texture, pigments, and translucency, just to name a few. What they are asking is “make it look natural” or make it look like it belongs in my mouth. I like to compare this to a bad “hair piece.” In other words, you can tell if a gentleman is wearing a bad hair piece because it does not look natural. A hairpiece that is undetectable and appears very natural can provides the best outcome for the person wearing it. The reality today is patients have access to unlimited information. With this access, they can form their own opinions on what they want before you have an opportunity to see them. Because of the higher dental IQ of today’s patients, we must acknowledge their desires and opinions, and also advise with the need to restore teeth aesthetically inclusive of function and occlusion. Changing the shape (contours, length, etc.) to improve the aesthetic results may also change the functional component. Sometimes this change can backfire if the existing function was not well understood. Our goal is to improve the outcome while maintaining ideal function for comfort and stability. In order to appreciate the relationship between aesthetics and function, let us first understand the design features of anterior teeth. These features contain specific contours and planes which are important for aesthetics and function. We will discuss both anterior and posterior teeth but with a strong emphasis on the anterior teeth.

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1.1

1  Functional Aesthetics

Anterior Teeth

The anterior teeth are designed primarily to tear food during the initial stages of mastication. The shape and root morphology of these teeth proves this point. The upper canine teeth usually have the longest and widest roots in the entire dentition [3]. This serves to not only grab and tear food but also withstand pressures during eccentric movements as a protective mechanism. In addition, the anterior teeth also provide soft tissue support, specifically the upper and lower lips. To fully appreciate and understand the anterior teeth, one must review the design and anatomy of the corresponding upper and lower anterior teeth. The maxillary central incisor, lateral incisor, and canine, as well as the mandibular incisor will be dissected into the following areas: (1) facial surface; (2) lingual surface; (3) incisal edge.

1.1.1 Maxillary Central Incisor (Fig. 1.4a, b) 1.1.1.1 Facial Surface We can look at this in two planes (lateral and facial planes). From the lateral side, we can see three distinct planes. The first one (in red) is the emergence from the CEJ. This is important since it supports the gingival margin and reflects a smooth transition from the root to enamel surfaces. If we continue past the emergence, the second plane (in green) exhibits a flatter plane that is slightly more lingual. The Fig. 1.4 (a) Anatomy of Maxillary Central Incisor from the facial, lingual, mesial, distal, and incisal views. (b) Maxillary Central Incisor illustrating anatomical landmarks from facial, lingual, mesial, distal, and incisal views

a

b

1.1  Anterior Teeth

5

angle of this plane moves inward (lingual) to more than two-third (2/3) the way. The final plane is at the final one-third (1/3) (in blue) and again appears to be slightly tipped lingual and ends at the incisal edge. These three planes are important when designing anterior teeth. The purpose of these planes (especially the last two) is related to lip support and phonetics. The maxillary central incisor is supported on the facial side by both upper and lower lips, while the tongue provides this same support on the lingual side. Phonetics is generated with air flow and the coordination of the tongue and lips. We will discuss further in Chaps. 6 and 7. From the facial side, we usually do not see the three planes as distinctly described from the lateral side, but we do see a difference between the mesial and distal contours. The mesial incisal contour is less convex than the distal one. The circumference of the convexity can be further distinguished when drawn out, and this creates differences in the incisal embrasures such that as we move away from the central incisors, we find the embrasure spaces increasing. Another way to view this is to divide the facial surfaces into thirds. Here, if you were to extend or continue to follow the contours of the mesial facial incisal line angle, it will form an imaginary circle. The circle at the distal will occupy two-third (2/3) of the facial surface, while the mesial side only occupies one-third (1/3) (see Fig. 1.4 (a and b) facial surface). In addition, the second plane as seen from the lateral side appears to be flat when viewing it from the labial side. When taking photos of these teeth from the labial side, you will observe this plane by noticing the light reflection from the camera flash appears at the mesial and distal facial line angles.

1.1.1.2 Lingual Surface Similarly, we will view this side of the central incisor from the same two planes (lateral and lingual planes). From the lateral side, the cervical area begins with a cingulum (in yellow). This bulbous area does in fact have a purpose, which is related to phonetics. In many cases laboratories fail to create proper cingulum on their restorations. This may be due to a lack of detail requested by the dentist, or simply the lab not paying attention to these details. Either way, it must be the role of the dentist to outline the importance of this landmark to the laboratory. This part of the surface has a specific purpose and will be discussed in further details later in Chap. 7. Continuing from the end of the cingulum, the lingual surface becomes concave and extends toward the incisal edge. This concavity is outlined by both mesial and distal marginal ridges (in orange and purple, respectively). In most cases these marginal ridges are used as an outline or support during protrusive movements of the lower anterior teeth. The goal is to allow the posterior teeth to disclude during protrusive movements. 1.1.1.3 Incisal Edge The incisal edge of this tooth is very significant. Most importantly this position will provide both proper aesthetics, phonetics and function. The incisal edge must be accurately positioned in both a horizontal and a vertical position. At a relaxed position, our upper lip drapes over the facial surface, while the lower lip rests on the incisal facial one-third (1/3) of the central incisor. In addition, the tongue rests against the lingual surface. It is very important to remember that when restoring

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central incisors, the position of the incisal edge is paramount. Any deviation away from ideal incisal edge position will affect how the upper and lower lips relate to the tooth position. It is a common complaint of dental laboratories that preparations in the incisal one-third (1/3) of the central incisors are usually not adequate, and as a result the incisal edge position is usually restored too thick facially. Depending on the thickness, this may slightly change the lower lip position as well as alter the function of how the mandibular teeth interact with the new incisal edge position.

1.1.2 Maxillary Lateral Incisor (Fig. 1.5a, b) 1.1.2.1 Facial Surface From the lateral view, there is a similar pattern of three facial planes, but smoother and less prominent. The facial surface of this tooth is similar to the central incisor, except for the size and shape. The mesial line angle is slightly rounded, while the distal is more curved. As a result, the embrasures between the mesial and distal will differ in size, with the distal embrasure being larger. In addition, there is a distinct flat facial plane (in green) observed on this surface that sometimes can take up most of the surface of this tooth. The size of this tooth is narrower and shorter as compared to the central incisor. When viewing the facial surfaces of the upper anterior teeth, you Fig. 1.5 (a) Anatomy of Maxillary Lateral Incisor from the facial, lingual, mesial, distal, and incisal views. (b) Maxillary Lateral Incisor illustrating anatomical landmarks from facial, lingual, mesial, distal, and incisal views

a

b

1.1  Anterior Teeth

7

will see a distinct incisal “step” between the central and lateral incisors. It is important to remember that the lateral incisor is designed to be shorter incisally to avoid a possible interference with the mandibular canine during protrusive movements.

1.1.2.2 Lingual Surface The lateral side again is very similar to the central incisor. The cingulum and the concavity (in yellow) are not as pronounced. From the lingual side, both mesial and distal marginal ridges (in purple and orange, respectively) exist to aid in anterior guidance to help separate the posterior teeth. 1.1.2.3 Incisal Edge The incisal edge on this tooth can appear to be straight or curved. Either way, it will follow the contour of the maxillary central incisor.

1.1.3 Maxillary Canine (Fig. 1.6a, b) 1.1.3.1 Facial Surface The lateral view of this tooth begins with the emergence and continually follows a concave contour till the incisal edge. However, from the labial side, this tooth has two planes that change at a demarcation point. The first part of the plane begins at Fig. 1.6 (a) Anatomy of Maxillary Canine from the facial, lingual, mesial, distal, and incisal views. (b) Maxillary Canine illustrating anatomical landmarks from facial, lingual, mesial, distal, and incisal views

a

b

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the mesial contact area and continues to approximately mid one-third (1/3) of the facial surface (in purple). At this point, there is a distinctive line angle (orange dotted line) that demarcates the remaining two-third (2/3) of the facial surface. Along with this demarcation, this marks the longest part of the tooth incisal. The remaining facial two-third (2/3) distal to the demarcation line is flat (in blue), while the mesial one-third (1/3) is more rounded as it approaches the contact area toward the distal of the lateral incisor.

1.1.3.2 Lingual Surface The maxillary canine’s lingual surface has a distinctive cingulum (in yellow) followed by a relatively straight lingual surface that extends to the longest incisal point on the facial side. In some cases, you will find mesial and distal marginal ridges (in orange and pink, respectively), and in some others, you will not. 1.1.3.3 Incisal Surface When viewing this tooth from this angle, you will notice that the mesial third appears thicker (labiolingual) than the distal two-thirds. This would make sense when you understand that canine guidance usually occurs on the mesial side during excursive movements.

1.1.4 Mandibular Incisors (Fig. 1.7a, b) 1.1.4.1 Facial Surface The facial surface of these teeth has a very distinct plane. Most of the facial surface of the mandibular incisors are flat, extending from the incisal edge toward the cervical area (in red). This plane tapers toward the cervical of this tooth where the widest part of the plane is at the incisal edge that the thinnest at the 1–2 mm from the CEJ. When viewing this tooth from the facial side, you will see the mesial and distal portions of the facial surface having a softer look. This is due to the change in the plane from the flat portion to a more rounded surface. This demarcation or change in the facial angle reflective of the line angles. The lateral view of these teeth will further illustrate these characteristics. It is important to understand that there is a very well defined incisal-labial line angle. This angle is vitally important in establishing a proper natural incisal contact against the lingual side of its opposing anterior tooth. The incisal edge is flat from the labial to lingual sides. 1.1.4.2 Lingual Surface The lingual side of these mandibular teeth also has two contours. The lingual incisal one-third is relatively flat but then becomes convex toward the cervical one-third. In most cases, you will see this in the form of a cingulum (in blue). 1.1.4.3 Incisal Surface When viewing these teeth from the incisal, all of the facial contours as described earlier become more visible. For example, the flat facial plane and both mesial/distal

1.1  Anterior Teeth Fig. 1.7 (a) Anatomy of Mandibular Central Incisor from the facial, lingual, mesial, distal, and incisal views. (b) Mandibular Central Incisor illustrating anatomical landmarks from facial, lingual, mesial, distal, and incisal views

9

a

b

line angles can be clearly seen here. In addition, the overall shape can take on a more convex appearance.

1.1.5 Mandibular Canine 1.1.5.1 Facial Surface The mandibular canine can be described in a similar fashion to the maxillary canine. It is smaller is size as compared to its opposing friend, and also has two planes. The incisal mesial one-third starts at the mesial facial line angle extending toward the highest point to which this ends the mesial plane. The second plane which comprises of the remaining two-thirds begins from the highest incisal point and tapers distally to form a rounded line angle. This point of transition is what separates the mesial and distal portions and represents the highest mark incisal. Remember, the height of this tooth is designed to provide adequate function against the opposing maxillary canine. Again, just like the maxillary canine, this represents the transition tooth between the anterior and posterior teeth. From the labial side (mesial or distal), this tooth exhibits a continuous taper toward the cervical, much like a convex shape. 1.1.5.2 Lingual Surface The lingual surface forms a concave surface starting at the incisal edge and terminating at the cingulum. In most cases this concave surface is very subtle and appears fairly straight.

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1.1.5.3 Incisal Surface When viewing this tooth from this angle, you will continue to see the same pattern as seen in the central incisors, i.e., the facial surface may appear convex, while the lingual surface may appear concave. The shape and contours of anterior teeth provide three important roles: phonetics, function, and vertical dimension. In the infancy period, tooth buds are genetically programmed to develop and eventually erupt into the oral cavity. We know from eruption sequencing that the mandibular anterior teeth (central incisors) are the first ones to develop and erupt, followed by the maxillary anterior teeth (central incisors). As these teeth continue to erupt, they are supported by the lips (upper and lower) and tongue. The soft tissues provide a positioning guide as these teeth erupt. Eventually at about 9 months of age, anterior teeth are finally occluding when the elevator masseter muscles contract. This anterior stop completes the tripod of stability between the TMJs and the anterior teeth. This anterior stop establishes the present vertical dimension of occlusion (Fig. 1.8). On the other hand, when the mandibular and maxillary anterior teeth are not in contact, they are at rest. Here, teeth are slightly apart, but the upper lip drapes over the two-third (2/3) of the maxillary central incisor, while the lower lip rests over the incisal third. On the lingual side, the tongue is positioned and rests against the cingulum of the central incisors, and the hard palate. This balance of muscle force of the tongue and lips keeps the anterior teeth in place (see Fig. 1.9). This place is also DECIDUOUS DENTITION 5 months in utero

MIXED DENTITION

2 years ( ± 6 mos)

PERMANENT DENTITION

11 years (± 9 mos)

7 years (± 9 mos)

7 months in utero PRENATAL 3 years (± 6 mos)

12 years (± 6 mos)

Birth 8 years (± 9 mos) 6 mos (± 2 mos)

4 years (± 9 mos)

15 years (± 6 mos)

9 mos (± 2 mos) 9 years (± 9 mos)

5 years (± 9 mos)

21 years

1 year (± 3 mos)

6 years (± 9 mos)

18 mos (± 3 mos)

Infancy

Early childhood (Pre-school age)

35 years

10 years (± 9 mos)

Late childhood (school age)

Fig. 1.8  Tooth eruption sequence for both primary and adult dentitions

Adolescence and adulthood

1.1  Anterior Teeth

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Fig. 1.9  Neutral zone of the anterior segment outlined by both lips and tongue Fig. 1.10  Neutral zone from occlusal view of maxillary teeth

termed the neutral zone. We find a similar pattern in the posterior teeth, but the neutral boundaries are controlled by the tongue and buccinators muscles (see Fig. 1.10). It is important to respect the neutral zone when restoring anterior teeth. Anterior restorations are often made without conformation of the patient’s neutral zone. This will result in the patient not feeling comfortable. If this is the case, it would be recommended that the restoration be adjusted quickly. Over time, a tooth with a restoration that is violating the neutral zone may change position as a compensatory mechanism. This change will affect the patient function over time. This concept is discussed further in Chap. 3.

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As mentioned earlier, part of the function of anterior teeth is to tear food during the initial stages of mastication. In addition, the anterior teeth also play an important role in phonetics. Phonetics is a sound created from the movement of air from the lungs (via vocal cords) through the mouth to create sound. The sound is created by both soft and hard tissues in the mouth. The importance of anterior teeth role in phonetics is clearly evident when you compare the phonetics of an edentulous patient versus one that is not. The edentulous patient will have trouble enunciating words compared to the dentulous one due to the lack of lip support (that the teeth would normally provide). This subject will be discussed in more detail in Chap. 7. Specifically, when restoring anterior teeth, we test the following sounds: “F” or “V,” “T” or “D” and “S.” If the design (or shape) and position of restorations are correct, then we expect the phonetics be clean and concise.

1.2

Smile Zone

Now that we have an understanding of the contours of anterior teeth and how this plays an important role in phonetics and function; the aesthetics component of anterior teeth is just as important. Initially, this is what patient’s pay close attention to, and over time it is the function that keeps the patient comfortable and stable. From replacing a single anterior tooth to redesigning an entire smile, anterior aesthetic treatment has limitations and boundaries that must be respected. This area can be referred to as the smile zone. It can be defined as the area between the commissaries, and the upper and lower lips. When our patient fully smiles, the facial muscles fully contract exposing the smile zone. We see various criteria on display that are related to both teeth and gingiva. This can be referred to as one’s own “smile fingerprint.” It is just as unique as the individual face. For example, Fig. 1.11a,b illustrates two different  smile zones outlined in “gray.” The patient illustrated in Fig.  1.11b has thinner lips, and the display is wider showing more maxillary and mandibular teeth as compared to the patient in Fig. 1.11a. The smile zone has seven criteria for teeth and three for the gingiva display. They are the following: Teeth 1. Length to width ratio 2. Golden Proportion 3. Axial inclination 4. Depth of incisal embrasure space 5. Central embrasure space 6. Posterior Occlusal plane 7. Buccal Corridor

Gingiva 1. Gingival position and balance 2. Papillary position 3. Lip hypermobility

In addition to the above criteria, the upper and lower teeth that make up the smile zone are positioned in a specific space. As mentioned earlier in this chapter, the

1.2  Smile Zone Fig. 1.11 (a) Smile zone with thicker lips with less display of teeth. (b) Smile zone with thinner lips with more display of teeth

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a

b

teeth are maintained in this space by soft tissue that includes the lips, tongue, and buccal mucosa. Figures 1.9 and 1.10 illustrate the boundaries that form the neutral zone. One of the goals in providing ideal aesthetic treatment is to change the shape and size of the anterior teeth. The design of the new anterior restorations must not only be respectful of these boundaries of the smile zone but also be able to function in comfort within the neutral zone.

1.2.1 Teeth 1. Length to width ratio: When evaluating any smile, the maxillary central incisors are the center point. The evaluation of the  symmetry in a smile begins with these two teeth. Studies of unworn maxillary central incisors exhibit a ratio between the length and width of approximately 80%, i.e., the width of any given unworn maxillary central incisor is approximately 80% of the corresponding length [4, 5]. Figure 1.12 illustrates this relationship. This statistic is valuable when central incisors exhibit any amount of tooth wear. For example,

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Fig. 1.12  Length to width ratio used to calculate the ideal length of Maxillary Central Incisor

Fig. 1.13  Calculation of ideal length of Maxillary Central Incisor on a worn dentition

if a central incisor has wear, then pick the best of the two incisors and measure the width. Multiply this number by a factor of 1.25 (100/80 rule). The calculated number will be the ideal length of the same tooth. This new length can also provide you with information on much tooth wear has occurred. Figure 1.13 illustrates this calculation. In this example, the original length (6.68 mm) was subtracted from the new calculated length (10.25  mm). This difference is divided by the new length, which will provide you with a percentage of tooth loss (from the original length). In Fig.  1.13, the left central incisor has lost approximately 35% of its tooth structure. This is of great value when discussing the extent of tooth loss with a patient. 2 . Golden proportion: The golden proportion rule should be used as a guide and not a rule. It is based on ideal proportions as seen in nature that are pleasing to the eye. A golden proportion ruler can be used to evaluate if the teeth in the smile zone are of ideal proportion [6]. It is recommended to use a grid as seen in Fig. 1.14 (courtesy of Bayview Dental Laboratory, Chesapeake, VA, USA). The

1.2  Smile Zone

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Fig. 1.14  Golden Proportion Ruler illustrating 9 mm width of Maxillary Central Incisor

Fig. 1.15  Maxillary cast depicted on three different golden proportions. Case example shows golden proportion is ideal when width of central incisor is approximately 8.5 mm

grid has reference points related to the width of the maxillary central incisors, and the total width from the mesial facial portion from maxillary canine to canine. Figure 1.14 illustrates a section of the ruler with two numbers. Here, the width of the central incisors  is 9.0 mm and the distance from canine to canine is 36 mm. Figure 1.15 illustrates how to use the models on the grid to find the ideal or closest proportion ratio. Once we have an idea of what is the closest ratio on the ruler, a wax up can be completed and verified on the same grid. 3 . Axial inclination: Axial inclinations of teeth are determined by the closure force and path. The mandible does not close in a true vertical manner due to its hinge axis. Since it also closes in an arc pattern, the forces upon closure are more directed in vertical and mesial direction [7]. We expect to see posterior teeth positioned in the mesial direction. Anterior teeth are positioned based on the vertical and horizontal overlap. Ideally, anterior and posterior teeth on the same side should all be in a similar pattern in a more mesial/vertical position. Figure 1.16 illustrates this ideal position. Here the axial inclinations of both posterior and anterior are parallel to each other.

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Fig. 1.16  Ideal axial inclination of anterior and posterior teeth

4. Depth of incisal embrasure space: Earlier in this chapter we discussed the anatomical features of the maxillary teeth. Due to the various convexities, the embrasures become larger as we move away from the maxillary central incisors [8, 9]. Figure 1.17 outlines the ideal embrasures from the central incisors to the corresponding canine teeth. Figures 1.17 and 1.18 illustrate how restoring anterior teeth can recapture ideal embrasures. 5. Central embrasure + posterior occlusal plane: Central incisal embrasure line should be perpendicular to the long axis of both central incisors. Any canting in the incisal edge or the axial inclination should be corrected as the two central incisors are the focal point in any smile [8]. In addition, the posterior maxillary occlusal plane should be parallel to the outline of the lower lip. Figure 1.19 illustrates the relationship of the maxillary anterior and posterior teeth (blue line) following a plane similar to that of the outline of the lower lip (red line). 6. Buccal corridor: The buccal corridor exists in posterior area between the posterior teeth and the soft tissue. To evaluate this area, a photograph is taken while the patient is smiling. An attractive smile has medium fullness in the arch form, symmetry, and no dead space (from missing or overlapping teeth) [10–13]. Figure 1.20 illustrates a balanced buccal corridor that does not have any dead space. On the other hand, Fig. 1.21 illustrates a patient with a left buccal corridor deficiency. In this case, the bicuspid almost disappears as it is hidden behind the left cuspid. This becomes more obvious when comparing to the patient’s righthand side.

1.2.2 Gingiva 1. Gingival position and balance: The gingival zenith (position) which is the highest point of a gingival margin has been studied. The data indicates that the zenith on the maxillary central incisors are approximately 1 mm distal to the long axis of the same tooth, while the lateral incisors were 0.4  mm from the long axis while the canine teeth exhibited the gingival zenith at the same long axis [14–16].

1.2  Smile Zone

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Fig. 1.17  Ideal incisal embrasures, papilla position, and gingival margins of Maxillary anterior teeth

Fig. 1.18 (a) Case example of disproportionate gingival margins, papilla position, and incisal embrasures. (b) Same case example restored to ideal gingival margins, papilla position, and incisal embrasures

a

b

Figure  1.18a illustrates compromised gingival position and balance, and Fig.  1.18b is restored (with a combination of grafting) creating ideal gingival position and balance. 2 . Papillary position: It has been documented that the papillary position is related to the proximal contact [17, 18], and we move away from the central incisors, the contacts moves more apical, and thus the papilla follows the same pattern. Figure 1.18 also illustrates this point. 3. Lip hypermobility: This becomes a concern aesthetically when a patient’s lip moves beyond the limits thus exposing more gingival tissue during a smile. This is sometimes referred to as a “gummy” smile. The Repose and E Smile photographs

18 Fig. 1.19 Posterior occlusal plane in reference to the lower lip line. Central embrasure of Maxillary central incisors perpendicular to incisal edge plane

Fig. 1.20  Buccal corridor ideal as outlined in color showing full display of posterior teeth during smile view

Fig. 1.21  Buccal corridor compromised on the left side where left bicuspid is hidden to the left cuspid

1  Functional Aesthetics

1.3  Posterior Teeth

“REPOSE” VIEW

19

“E SMILE” VIEW

Fig. 1.22  Excess gingival display during smile view as a result of wear with compensatory eruption and hypermobile lip

are ideal to view the mobility of the upper lip. This becomes important for the dentist since we know that patients who restoratively correct their smiles tend to automatically increase the  movement of their upper lip as a consequence of increased confidence. There are four main reasons why patients may have excessive gingival display. Vertical maxillary excess, short upper lip, hypermobile lip, and wear with compensatory eruption. It is important to help your patient understand a possible cause of any excessive gingival display. This will improve the expectations of the final results and will not cause any misunderstanding. Figure  1.22 illustrates a patient showing adequate incisal edge position in the “repose” or “rest” photograph.” In the “E Smile” view, the smile shows excess in gingival display. It is important to note that there exists anterior gingival symmetry on the patient’s left side; however, we don’t see the same result on the patient’s right side. Here tooth #8 (1.1) is worn down (incisally) with compensatory eruption. The gingival margin of both #8 (1.1), and #9 (2.1) are not symmetrical.

1.3

Posterior Teeth

The posterior teeth are primarily used for grinding food into a bolus (when mixed with saliva). The design of posterior teeth clearly demonstrates this by having different morphology and root design which can withstand significant increased forces. As mentioned earlier, the canines (maxillary and mandibular) represent the transition teeth from anterior to posterior teeth. Beginning with bicuspids (from having two cusps) to the molars (having minimal of four cusps), these teeth provide adequate mastication of food bolus through the corresponding interaction during chewing cycles. The chewing cycle primarily is a combination of both vertical and horizontal movements of the mandible. Usually we see this pattern in patients with Angle classifications of Class I and II. However, Class III usually have an anterior “end to end” or slight underbite. These patient’s chewing cycles are mostly vertical in nature as they do not need any excursive movements to function since they do not possess the ability to have anterior guidance.

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1  Functional Aesthetics

Designing and restoring anterior teeth predictably requires careful planning along with an understanding of the dental  anatomy. This chapter has provided a good understanding of the relationship between the anatomy of anterior teeth and the importance of function with anterior guidance and speech [19]. The maxillary central incisor edge must be considered as a reference point to ideal aesthetics, function, and phonetics. This reference has to be predictably positioned to provide the patient with comfort of lip support, anterior guidance, and proper phonetics. Any deviation of this position will change or compromise aesthetics, function, and possibly phonetics. That is the difference between aesthetics and functional aesthetics. The former focuses on the facial aspects of anterior restorations, while the latter provides a better understanding of the lingual design. The lingual side also has a direct relationship to the mandibular anterior teeth to provide function such as anterior guidance and the initial stages of chewing. Both lingual and facial contours come together at the incisal edge position. As you continue exploring the remaining chapters, you will understand that incisal edge position of both maxillary and mandibular central incisors is critical in establishing proper occlusion and function.

References 1. González EL, Pérez BP, Sánchez JAS, Acinas MMR (2010) Dental aesthetics as an expression of culture and ritual. BDJ 208(2):77–80. https://doi.org/10.1038/sj.bdj.2010.53 2. Ring M E.,DDS (1985) Dentistry An Illustrated History, 1st edn. Harry Abrams, Inc., New York 3. Ash MM Jr (1984) Wheeler’s dental anatomy, physiology, and occlusion, 6th edn. W.B. Saunders Company, Philadelphia, PA 4. Magne P, Dent M, Gallucci GO (2003) Anatomic crown width/length ratios of unworn and worn maxillary teeth in white subjects. J Prosthet Dent 89:453–461 5. Tsukiyama T, Marcushamer E, Griffin TJ, Arguello E, Gallucci GO (2010) Comparison of the anatomic crown width/length ratios of unworn and worn maxillary teeth in Asian and white subjects. J Prosthet Dent 107(1):11–16. https://doi.org/10.1016/S0022-3913(12)60009-2 6. Levin EI, Ch BD, Payne H, Arb GA (1978) Dental esthetics and the golden proportion. J Prosthet Dent 40(3):244–252 7. Zarif Najafi H, Oshagh M, Khalili MH, Torkan S (2015) Esthetic evaluation of incisor inclination in smiling profiles with respect to mandibular position. Am J Orthod Dentofac Orthop 148(3):387–395. https://doi.org/10.1016/j.ajodo.2015.05.016 8. Baharav H, Kupershmit I, Cardash H, Eng RCS (2009) Comparison between incisal embrasures of natural and prosthetically restored maxillary anterior teeth. J Prosthet Dent 101(3):200–204. https://doi.org/10.1016/S0022-3913(09)60030-5 9. Implications C (2005) An analysis of maxillary anterior teeth: facial and dental proportions. J Prosthet Dent 94(6):6–10 10. Moore T, Southard KA, Casko JS, Qian F, Southard TE (2005) Buccal corridors and smile esthetics. Am J Orthod Dentofac Orthop 127(2):208–213 11. Janson G, Branco N, Fernandes T, Sathier R, Garib D, Lauris J (2011) Influence of orthodontic treatment, midline position, buccal corridor and smile arc on smile attractiveness. Int J Orthod Orthop 81(1):153–161 12. Parrini S, Rossini G, Castroflorio T, Fortini A, Deregibus A, Debernardi C (2016) Laypeople’s perceptions of frontal smile esthetics: a systematic review. Am J Orthod Dentofac Orthop 150(5):740–750. https://doi.org/10.1016/j.ajodo.2016.06.022 13. Nascimento DC, Machado WL, Alan M, Bittencourt V (2012) Influence of buccal corridor dimension on smile esthetics. Dental Press J Orthod 17(5)

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14. Koidou VP, Chatzopoulos GS, Rosenstiel SF (2018) Quantification of facial and smile esthetics. J Prosthet Dent 119(2):270–277. https://doi.org/10.1016/j.prosdent.2017.04.002 15. Correa BD, Vieira Bittencourt MA, Machado AW (2014) Influence of maxillary canine gingival margin asymmetries on the perception of smile esthetics among orthodontists and laypersons. Am J Orthod Dentofac Orthop 145(1):55–63. https://doi.org/10.1016/j.ajodo.2013.09.010 16. Chu JS, Jocelyn TAN JH-P, Christian F.J. Stappert CFJ, Tarnow DP (2009) Gingival Zenith Positions and Levels of the Maxillary Anterior Dentition. J Esthet Restor Dent. 21(2):113–120. 17. Chu S, Tarnow D, Tan J (2009) Papilla proportions in the maxillary anterior dentition. Int J Periodontics Restorative Dent 29(4):385–393 18. Foulger TE, Tredwin CJ, Gill DS, Moles DR, Milan R (2010) Summary of: the influence of varying maxillary incisal edge embrasure space and interproximal contact area dimensions on perceived smile aesthetics. Br Dent J 209(3):126–127. https://doi.org/10.1038/sj.bdj.2010.698 19. Heinlein WD (1980) Anterior teeth: esthetics and function. J Prosthet Dent 44(4):389–393

2

Functional Occlusion: Understanding and Thinking

Some are born great, some achieve greatness, and some have greatness thrust upon them. William Shakespeare

Contents 2.1  Discussion 2.2  Occlusion 2.3  History 2.4  Temporomandibular Joint 2.5  Chewing Cycle 2.6  Occlusal Disease Classification References

 23  24  28  29  31  32  34

2.1  Discussion Functional occlusion has been studied and debated for many decades by highly regarded dental professionals with documentation of how patterns of occlusions have evolved in our species over time [1]. Besides dentists, others like anthropologists have also  studied patterns of occlusion from the earliest days of man. These include both anterior and posterior teeth changing over many generations based on wear patterns. They have documented that earlier “man” exhibited smaller skulls with larger maxilla and mandibles. Larger muscles along with a gritty diet ultimately lead to flattening of cusps and fossa. This relationship results in a flat plane occlusion [2]. This motion of chewing was more circular in nature. The discovery of fire (500 million years ago) [3] allowed for softer foods and less occlusal stress needed to chew, but the flat plane occlusion still dominated for millions of years to follow. As evolution continued, “modern man’s” skeletal structures changed due to a more upright posture. Skull base increased while the maxilla and mandible © Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_2

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both decreased in size. Eventually, civilization evolved into producing low abrasive foods (wheat, corn, and potatoes) which required less chewing time. With the advent of the industrial revolution, foods were produced with even less abrasiveness. As a result, this evolution of the human race’s dentition has gone from a flat plane to a more preserved cusp and fossa relationships. Thus, we deal with chewing patterns that are far more complex as compared to our ancestors. Over the years I have spoken to many dentists about several different clinical topics. Invariably, the conversation of occlusion is usually avoided. When asked about occlusion, some of the explanations include “too complex,” or “not as important,” and “I know enough about occlusion….” I used to have similar opinions on this subject too. However, the subject of occlusion is not complex, and to be honest, most dentists do not know enough on this subject. They simply understand occlusion as the relationship of just the maxillary and mandibular teeth and is important only at the end of a dental procedure. Terms used to describe this relationship are centric occlusion, or maximum intercuspation (MIP), and centric relation. There is much discussion and sometimes controversy regarding the correct term to be used not to mention differing opinions on occlusal philosophy [4, 5]. This chapter will not discuss this controversy but rather explain the importance of occlusion and function. It is important to note that achieving occlusal stability should be of paramount importance to all restorative dentists, and once a dentist understands the relationship between function and occlusion, there seems to be an increased skill level for diagnosing and treatment planning with precision and predictability [6]. Our discussion will begin with a simple concept of occlusion and follow with how function relates to occlusion.

2.2  Occlusion Occlusion can be described as a relationship of one or more teeth in contact with each other [7, 8]. Although this description is correct, occlusion is just a small part of a larger dynamic in place. Thus, understanding the concept of occlusion must Fig. 2.1  Occlusion starts at the temporomandibular joints and ends with anterior teeth

2.2 Occlusion

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DECIDUOUS DENTITION 5 months in utero

MIXED DENTITION

2 years (± 6 mos)

PERMANENT DENTITION

11 years (± 9 mos)

7 years (± 9 mos)

7 months in utero PRENATAL 3 years (± 6 mos)

12 years (± 6 mos)

Birth 8 years (± 9 mos) 6 mos (± 2 mos)

4 years (± 9 mos)

15 years (± 6 mos)

9 mos (± 2 mos) 9 years (± 9 mos)

5 years (± 9 mos)

21 years

1 year (± 3 mos)

6 years (± 9 mos)

18 mos (± 3 mos)

Infancy

Early childhood (Pre-school age)

35 years

10 years (± 9 mos)

Late childhood (school age)

Adolescence and adulthood

http://what-when-how.com/dental-anatomy-physiology-and-occlusion/development-and-eruption-of-the-teeth-dental-anatomy -physiology-and--occlusion-part-1

Fig. 2.2  Eruption sequence of both primary and secondary human dentition

have both a starting and an ending point. Figure 2.1 illustrates a generic skull with two points of interest. Here the temporomandibular joint represents the starting point while the anterior teeth the end point of occlusion. We will discuss the relevance of these two points of interest later as each of these two points are referred to as determinates of occlusion. What remains between the temporomandibular joints and the anterior teeth are the remaining posterior teeth. Eruption sequence supports this same relationship of occlusion. We know the mandibular anterior teeth erupt first, then followed by the maxillary ones. With a functioning temporomandibular joint, over time newly erupted anterior teeth make contact (see Fig. 2.2). As Fig. 2.2 illustrates, by 9 months of age, mandibular and maxillary central and lateral incisors make contact. This forms three stable points of reference, i.e., both TMJs and the anterior teeth. Figure 2.3 illustrates this idea with the analogy of a “stool.” Stability is created when elevator muscles contract on both sides, and the anterior teeth come into firm contact. Much like the three-legged stool on the right side of Fig. 2.3. If equal force is applied on the stool (on a flat, leveled floor), then stability is reached. The stool will not fall or move. Similarly, when temporomandibular joints are seated and anterior teeth are in full contact, we have stability in both the anterior and posterior areas of the masticatory system. The relationship of the anterior contact will be discussed later in this chapter. Another way to describe this is to consider the mandible much like a class III lever [9]. Lever systems are comprised of a fulcrum, force, and load. Depending on where the

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Fig. 2.3  Analogy depicting the stability of a stool with that of mandible when both temporomandibular joints are seated, and anterior teeth are in contact

Fig. 2.4  Mandible as a class III lever illustrating the location of the “force,” “fulcrum,” and “load”

fulcrum is located, there are three classes of levers. Figure 2.4 illustrates the mandible as a class III lever system. Here the “fulcrum” is at the temporomandibular joints, the “force” is represented by the muscles of mastication (specifically the masseter, lateral pterygoid, and temporalis), and the “load” is the occlusion (anterior

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teeth). Since the force exerted (muscle contraction) is closer to the posterior teeth, there is more “load” experienced on the posterior teeth as compared to the anterior ones. The further a tooth is from the force of compression, the less impact it has on the temporomandibular joint. Anterior teeth are the furthest away from the force of compression. With this in mind, as the anterior teeth begins to couple during excursive movements, it has been noted that a decrease in muscle activity (elevator muscles) occurs [10], and the amount of force exerted on anterior teeth during coupling is approximately one-third as compared to posterior teeth that are fully engaged [7]. For example, if you were to bring your anterior teeth together (end to end) and bite as hard as you can, you will notice very little or no contraction of the compressive muscles (Masseter, Temporalis). In addition, there seems to be a correlation between the number of posterior contacts and the amount of force. The more posterior contacts available, the greater the force exertion. This will explain why posterior teeth are designed to handle excessive loads as they have a wider occlusal surface and multi-root development. On the other hand, since the amount of load is considerably less in the anterior area, these teeth are thinner and are not designed to handle forces of mastication such as those experienced in the posterior teeth. The occlusal anatomy of the teeth needs to function in harmony with the structures that control the movement of the mandible. These structures are known as the determinants of occlusion and is divided into posterior and anterior determinants. The posterior movement of the mandible is influenced by the temporomandibular joint, its ligaments, and the condylar path. This is described as the path the condyle takes down the articulating eminence during protrusive and lateral (left and right) movements. This is also termed condylar border movements. The angle of the condylar path can vary from one individual to another, but it is a fixed entity as long as there is no disease or trauma associated with the temporomandibular joint. In addition, the condylar path cannot be changed or altered by a restorative dentist (Fig. 2.5) [11].

Fig. 2.5  Anatomical landmarks of the temporomandibular joint

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The anterior movement of the mandible is influenced by the relationship of the maxillary and mandibular anterior teeth (central incisors), specifically, the horizontal and vertical relationship. During mandibular movements (protrusive or lateral excursive), the mandibular anterior teeth engage on the lingual surfaces of the maxillary anterior teeth. The steepness of this interaction determines the amount of vertical movement [12]. This anterior determinant can be altered by the restorative dentist to improve function. These determinants provide support and guidance for the stability of occlusion. With the posterior teeth working in harmony with the condyles, the posterior teeth provide vertical support for the arch, while the anterior teeth provide a horizontal guidance support [13]. In between all this are the occlusal contacts of the posterior and anterior teeth. It should be the goal of establish occlusal contacts that are within the border movements. For example, if the inclines of posterior teeth create interference on either working or balancing side, or a premature contact in centric relation, the mandible may change or alter the direction (with the help of the muscles of mastication) to avoid the interferences and work within a different boundary. Because the condylar path does not change during this compensatory movement [5], it adds stress to the system, mostly on muscles. This shift or reaction to the interferences creates more elevator muscle activity and also can shift the mandible anteriorly. Over time this can have a consequence on the anterior determinant as the existing angulation or lingual contours of the maxillary teeth become compromised.

2.3  History What would be considered an ideal occlusion? One that does not produce wear on teeth maintains a healthy periodontium and temporomandibular joint. This description is the expectation of today’s standards. However, this was not the case in the past, and the understanding of occlusion has evolved throughout history. Starting in the late 1800s, Dr. Von Spee proposed and supported bilateral group function and was considered the ideal occlusal scheme. Over time, this scheme produced much failure and destruction to the teeth, periodontal issues and TMJ problems ensued. This explanation at the time was simply considered acceptable, and the destruction or occlusal failure was accepted as an adaptive change. As a result, in the 1950s the thought process changed from bilateral group function to unilateral group function [4]. At that time, requirements for occlusal rehabilitation were created by PankeyMann-Schuyler and were the following: 1 . Maximum contact of teeth in centric relation. 2. Simultaneous contact of anterior and posterior teeth on the working side. 3. Anterior disclusion of posterior teeth in protrusive movement. 4. No contacts on the balancing side during excursive movements. 5. Selecting and restoring lower posterior occlusion to be in harmony with anterior guidance and condylar guidance.

2.4  Temporomandibular Joint

29

Eventually, it was determined that the canine teeth were structurally designed to handle lateral forces and provide protection to the posterior teeth. Hence canine-­ protected occlusion became more accepted [4, 14]. The requirements for a stable occlusion are the following: 1 . Equal intensity (stable stops) on all teeth while condyles are in centric relation. 2. Disclusion of all posterior teeth in protrusive movements. 3. Disclusion of all posterior teeth on the balancing side. 4. Noninterference of all posterior teeth on the working side. 5. Anterior guidance in harmony with the envelope of function. In practical terms, most patients are not likely do not have an existing ideal occlusal scheme as described above. The masticatory system like other systems in the body adapt to stresses over time. This can include parafunction, diet, and iatrogenic dentistry. Most dentists are not looking or understand how to verify if the patient’s occlusion is stable or unstable. Thus, when rendering treatment, it is possible that over time, the completed restorations create more instability through adaptation. For example, how many times have you heard your patient state that the restoration was “high” or “it was bothering me for a few days,” but after some time it felt normal. Furthermore, when occlusion is finally checked, patients are still under local anesthesia which truly does not allow the patient to feel their occlusion accurately. In addition, these patients require the need to return for additional occlusal adjustments. Although this method of checking a patient’s occlusion at the end of a procedure is needed, it is solely based on the patient’s habitual closure to the best of their ability. If we begin treatment with a goal to create a stable idealized occlusal relationship, then we can rely on this stable occlusal foundation for future treatment and maintenance [15]. A clear understanding of your patient’s occlusion is needed in order to solve the existing dental problems. The treatment planning process also includes analyzing the occlusion. This way of thinking can be a significant shift from the mindset of a typical dentist.

2.4  Temporomandibular Joint The term occlusion is interpreted by many dentists as just the teeth contacting together which is verified with articulating paper during the completion of a dental procedure. This is very different from function, as this relationship has more to do with movements of the mandible. Examples of movements include opening and closing the mandible, chewing, and swallowing. The mandible is the only part of the masticatory system that is mobile, and its anatomical landmark begins at the temporomandibular joint with the condyle seated in the glenoid fossa. In three dimensions (looking in a transverse plane), I want you to picture the glenoid fossa as a sideways “V” shaped space (sideways, much like “>”). The medial side is the

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Fig. 2.6  Location and outline of the glenoid fossa (outlined in the “blue” area, with medial to lateral outlined in “red”)

narrowest part of the “V.” The lateral side is the widest part. When fully seated, the mandibular condyles are braced in the glenoid fossa where most of the force is directed to the medial side or medial pole. In between these two bony surfaces is the disc assembly that is lubricated with synovial fluid (the slipperiest fluid produced in the body). This disc is wrapped around the entire condyle much like a “bucket handle.” The posterior part of this disc has a posterior band that is tethered on the back end of the condylar head and acts much like an elastic band. During opening, it is stretched as the disc advances with the condylar head (down the eminence), and upon closure disc assembly returns back and the posterior band reduces to maintain the disc on the condylar head during mandibular closure. During normal functioning movements, the mouth opens by having the depressor muscles contract (Lateral Pterygoid, Digastric) allowing the condyles to first rotate in a hinge. As further contraction occurs, the condyle changes from rotation to translation as it travels down the articulating eminence. At this point the mandible is fully open (yawning, or biting into a large food item). When the mandible is ready to close, the same muscles that opened the mandible release and allow the elevator muscles (temporalis, masseter, medial pterygoid) to contract translating the condylar head back up into the glenoid fossa. Once the teeth are in full contact (posterior and anterior), the disc assembly should be seated inside the glenoid fossa braced against the medial side of the fossa. In a normal, healthy functioning temporomandibular joint, as the mandible opens and closes, the disc assembly always maintains the same position on the condylar head. The disc assembly can change under stress (trauma, poor occlusion, parafunction) which will change the relationship of how the disc engages with the condylar head during these same

2.5  Chewing Cycle

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Fig. 2.7  Mandibular condyles seated in the glenoid fossa (outlined in “blue”) showing the medial side of the condyles toward the narrowed portion of the glenoid fossa

movements of the mandible. In Chap. 4, we will discuss this in more detail of how to interpret the temporomandibular joint during the complete comprehensive examination (Fig. 2.6).

2.5  Chewing Cycle Chewing begins as the food enters the mouth with the anterior teeth tearing and ripping food into smaller pieces. Depending on the size and hardness, the food is placed on the back molars, and based on the sensory mechanisms, controlled slow pressure occurs until the bolus has become less dense. The patterns have been studied extensively, and it has been reported as a combination of both vertical and lateral cycles. This motion continues until the bolus of food is ready for swallowing. During the chewing phase of mastication, there are differences of opinions as to whether the teeth are in contact or not. If they are not in contact, then they are very close being so, but there is some evidence that contacts do occur during the chewing cycle, but for a very short period of time (anywhere from 1/5 to 1/10 of a second) [16]. When the chewing cycle is complete, the mandible goes into a retruded position allowing both condyles to seat in the articulating eminence. It is important to note that the mandible can only retrude into the glenoid fossa when the lateral pterygoid muscles release (inferior belly) [17]. This contact and bracing allow the food bolus to be pushed by the tongue over the larynx and down into the esophagus (Figs. 2.7 and 2.8).

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Fig. 2.8  Sagittal view of the condyles fully braced in the Glenoid Fossae illustrating the bracing occurring on the medial side

2.6  Occlusal Disease Classification Today, one of the requirements for any dentist is to understand the patient’s occlusion by examination and observing signs of occlusal breakdown. These signs of occlusal breakdown can present itself in many ways. The most common signs that we see include worn and/or cracked teeth as well as abfractions. Other signs include tooth mobility, bone loss (compromised periodontal health), and failed restorations. This description of occlusal breakdown can also be accompanied with other signs including sore muscles, limited jaw movements, and TMJ symptoms. All of these signs together should indicate that your patient has some degree of occlusal disease. For the sake of simplicity, it would make sense to perhaps categorize the degree of occlusal disease thus allowing the dentist to approach treatment respective of the classification. The treatment planning aspect will be discussed further in Chap. 8. Before you restore any anterior teeth, it is critical that you understand the complete health of your patient’s masticatory system. The guidelines below are suggestions based on the weakest link in the masticatory system. The recommended treatment regimen can be integrated into the aesthetic treatment plan. Occlusal Disease Class I: • TMJ stable (no joint noise or pain) • Muscles of mastication—stable • Minimal or no tooth wear • Centric relation verified with a slide to maximum intercuspation TX Regiment: • No need to mount models • Treat caries and periodontal health

2.6  Occlusal Disease Classification

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• Restore structurally compromised teeth • Equilibration may or may not be needed Occlusal Disease Class II: • TMJ exhibits early signs of initial breakdown (lateral pole clicking) • Muscles of mastication—exhibit slight soreness • Minimal tooth wear • Centric relation verified with a slide to maximum intercuspation TX Regiment: • Mounting of models in centric relation recommended. • Occlusal analysis and DOTA. • Treat caries and restore structurally compromised teeth and periodontal health as part of creating a stable occlusion. • Equilibration may be required (reductive). Occlusal Disease Class III: • TMJ exhibits signs of continuous breakdown (lateral pole clicking and/or popping) • Muscles of mastication—exhibit slight to moderate soreness • Moderate tooth wear • Centric relation verified with a slide to maximum intercuspation TX Regiment: • • • • •

Deprogram or splint therapy if needed Treat caries and periodontal health Mounting of models in centric relation Occlusal analysis and DOTA Restore structurally compromised teeth as part of creating a stable occlusion • Equilibration will be required (reductive) Occlusal Disease Class IV: • TMJ exhibit signs of further breakdown (medial pole/click/popping/pain) • Muscles of mastication—exhibit moderate to severe soreness • Moderate to severe tooth wear • Centric relation cannot be verified TX Regiment: • Splint therapy to treat joint until TMJ is comfortable and pain free. MRI of the TMJ as needed • Treat caries and periodontal health • Once TMJ is stable, then occlusal analysis and DOTA • Determine restorative plan as needed to maintain occlusal stability

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• Equilibration will be required (combination of additive and reductive) The purpose of the. above categories is to allow you to think about the priorities as well as to make important clinical decisions regarding treatment.

References 1. D’Amico A (1961) Functional occlusion of the natural teeth of man. J Prosthet Dent 11(5):899–915 2. Neiburger EJ (1977) Flat-plane occlusion in the development of man. J Prosthet Dent 38(4):459–469. 3. James SR, Dennell RW, Gilbert AS, Lewis HT, Gowlett JAJ, Lynch TF, McGrew WC, Charles R. Peters CR, Pope GG, Stahl AB, James SR (1989) Hominid Use of Fire in the Lower and Middle Pleistocene: A Review of the Evidence [and Comments and Replies]. Curr Anthropol 30(1):1–26. 4. Williamson EH (1976) Occlusion: understanding or misunderstanding, vol 6(1), Jan 1976, pp 88–93 5. Cohen R (1956) The relationship of anterior guidance to condylar guidance in mandibular movement. J Prosthet Dent 6(6):758–767 6. Wiens JP, Priebe JW (2014) Occlusal stability. Dent Clin N Am 58:19–43. https://doi. org/10.1016/j.cden.2013.09.014 7. Levy, P.  H. (1899). A form and function concept of occlusion and the maxillomandibular relationship 8. Clark JR, Evans RD (2014) Functional Occlusion: I. A Review. J Orthod 28(1):76–81. 9. Jensen W (n.d.) Alternate occlusal schemes, p 66 10. Manns A, Chan C, Miralles R (1987) Influence of group function and canine guidance on electromyographic activity of elevator muscles. J Prosthet Dent 57(4):494–501. 11. Dawson PE (2007) Functional occlusion: from TMJ to smile design. Mosby Elsevier, St. Louis, MO 12. Schuyler CH (1953) Factors of occlusion applicable to restorative dentistry. J Prosthet Dent 3(6):772–782 13. Jensen WO (1991) Alternate occlusal schemes. J Prosthet Dent 65(1):54–55. 14. Alexander PC (1963) Analysis of the cuspid protective occlusion. J Prosthet Dent 13(2):309–317 15. Lauritzen AG (1951) Function, prime object of restorative dentistry; a definite procedure to obtain it. J Am Dent Assoc 42(5):523–534. https://doi.org/10.14219/jada.archive.1951.0081 16. van der Bilt A, Engelen L, Pereira LJ, van der Glas HW, Abbink JH (2006) Oral Physiology and Mastication. Physiol Behav. 89:22–27. 17. Jamieson CH (1962) Discussion of “the anatomy of the temporomandibular joint as it pertains to centric relation”. J Prosthet Dent 12(3):473–475.

3

The Envelope of Function: Understanding and Importance

Health is the greatest gift, contentment the greatest wealth, faithfulness the best relationship Buddha

Contents 3.1  Discussion 3.2  Mandibular Movements/Envelope of Motion 3.3  Envelope of Function 3.4  Restricted Envelope of Function 3.5  Verifying Envelope of Function/Technique References

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3.1  Discussion In the previous chapter (Chap. 2), we discussed the importance and understanding of the relationship between the mandibular and maxillary. This relationship extends to the temporomandibular joints as a perfected occlusion begins with equal intensity contacts (anterior and posterior) while both joints are seated in centric relation [1]. The anterior and posterior teeth have different functional roles within the masticatory system. The former begins the mastication process of tearing food and protects the posterior teeth during lateral or excursive movements, whereas the latter completes mastication (chewing) by providing enough surface area to help create a bolus, and plays a primary role in the swallowing mechanism (the act of swallowing bolus of food requires the posterior teeth to be in full contact). Understanding this relationship of both anterior and posterior teeth helps us appreciate the function of the masticatory system. In order for this system to be stable, occlusion plays a key role. As

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mentioned earlier, the anterior teeth help protect the posterior teeth during excursive movements. This role of protection is sometimes referred to as anterior guidance. Historically, the term anterior guidance was categorized into two occlusal thoughts: group function and canine guidance. Group function was also termed “balanced occlusion,” and this thought process (from Dr. von Spee—the term curve of Spee) was based on the understanding that mastication (movement to grinding food) is dependent upon both configuration of the temporomandibular joint and the occlusal anatomy of the teeth, which are interconnected [2]. This was later refuted as this concept may have been acceptable for complete dentures but was found to be destructive on the natural dentition and caused occlusal wear, periodontal involvement, or TMJ dysfunction. Canine guidance (also termed canine guidance, canine rise, or canine-protected occlusion) is disclusion of posterior teeth during excursive movements. It was determined that using the canine teeth in function caused an alteration in the motor impulse to the musculature, thereby decreasing muscle activity and reducing lateral forces on the periodontium [2]. In addition, the canine teeth have the best ideal crown to root ratio and have a higher lateral pressure threshold [3, 4]. As a result, it became more acceptable that the canine teeth were designed for this purpose.

3.2  Mandibular Movements/Envelope of Motion For the purposes of this chapter, we will make reference to canine guidance as anterior guidance. This movement is described as the anterior teeth (mandibular and maxillary) working together during excursive movements. This can include both left and right working sides  as well as protrusive movements. Working side movements begin with contraction of the lateral pterygoid muscles which result in translation of the mandibular condyle down the respective articulating eminence. When checking or examining for anterior guidance, the ideal place to start is centric relation. Here we expect to start at a centric relation contact point and when the mandible begins its translation in either direction (left or right), the condyle  that is translating is no longer in centric relation. As long as there is no posterior interferences noted on either working or balancing sides, we expect this movement to be effortless, smooth, and comfortable without any hesitation from our patient. In most instances, patients do have a discrepancy between centric relation and centric occlusion (or maximum intercuspation). This should not affect the movement, but in these patients, it is important to note that the condyle position in maximum intercuspation is slightly more down and forward in the eminence.  This may result in a ‘‘shorter’’ translation distance down the eminence which may also pick up more posterior interference along the way. Posterior teeth that interact or interfere during these lateral movements will result in two observations. One is restricted or limited movement (due to increased muscle activity), and the other is more effort by your patient to complete the movement. Either way, this may appear to be less comfortable for the patient. Protrusive movement begins when both left and right sides of the condyle translating down the eminence. The lingual surfaces of the maxillary anterior teeth can engage with the corresponding mandibular teeth during this movement. These movements of the mandible are referred to as functional movements

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and are thought of as movements associated with anatomical structures such as the temporomandibular joints and the maxillary and mandibular anterior teeth. The limits of the mandibular movements are also described as border movements. These border movements have been well documented for many decades and have remained unchanged. It was introduced by Dr. Ulf Posselt in 1952 as his understanding of mandibular movements was documented in three planes, Frontal, Horizontal, and Sagittal [5]. The limits for these movements are dependent on muscle contraction (muscles of mastication) and ligaments (posterior ligaments of the TMJ, capsular ligaments, and stylomandibular ligament) associated with the temporomandibular joints. This description has been called the “Envelope of Motion” [1]. Figures 3.1, 3.2, and 3.3 illustrate the border movements of the mandible in these three planes. The diagrams represent the outer border limits of the Fig. 3.1 Mandibular border movements from the frontal plane

Fig. 3.2 Mandibular border movements from the horizontal plane

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mandibular movement in each plane. Please note that this is not how the mandible moves during normal function (chewing, etc.) but is simply used to illustrate the limitations of the mandible [6–8]. During normal functioning movements, the patterns of these border movements can vary based on the type of food and velocity of the movements [9]. Of the three diagrams, Fig. 3.3 appears to be the one diagram that most clinicians can relate to or remember, that is the mandibular movements in

Fig. 3.3 Mandibular border movements from the sagittal plane

Fig. 3.4  Description of the envelope of motion and its corresponding limits

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the sagittal plane. We will explain this movement in more detail using the illustration of Fig. 3.4. Here, the border movements begin with the condyle rotating on it axis in the glenoid fossa outside of centric relation. Here the teeth are not in contact as the mandible is at rest position. As it continues to rotate (red line), it reaches a point where the lateral pterygoid muscles activate, causing translation (purple line), and the mandible begins to start opening to the point where the condyle has reached the maximum distance at the eminence due to the maximum contraction of the lateral pterygoid muscle. Since the mandible has reached its maximum opening, the lateral pterygoid muscle begins to release while the elevator muscles begin to contract, causing the mandible to begin closure (green line). The outer limit of this movement ends at the maximum protrusive position of the mandible. From here the elevator muscles continue to contract and the mandible returns toward the starting point of either the rest position or the complete occlusal contact (centric relation) position.

3.3  Envelope of Function The natural movement of the mandible during normal function occurs within these same limits of border movements in all the three planes. Sometimes these have been described as “free” movements within the envelope of motion, or also termed the “Envelope of Function.” There are limitations to these free functioning movements which are dictated by the shape, position, and contour of the maxillary anterior teeth, especially the incisal edge position and the lingual contours. Figure 3.5 illustrates the boundaries of the envelope of function. The facial contour or position of the tooth is supported by the lips and the tooth remains in this position naturally. The incisal edge

Fig. 3.5  Boundaries to the envelope of function

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a

b

c

Fig. 3.6  Envelope of function with three different axial inclinations of the maxillary incisor. Note: all three inclinations have the same incisal edge position, but each envelope of function is different

and lingual contours will determine whether the envelope of function is ether shallow or steep. It is important to note that regardless of the position of the maxillary central incisor, the limitations of the border movements (Envelope of motion) remain the same. However, what does change is the “free” movement or “Envelope of function” [1]. Figure 3.6 illustrate three positions (A: normal; B: upright; C: lingual inclined) of the maxillary central incisor. Each position of the maxillary central incisor has the same incisal edge position, lingual contours, and the envelope of motion (border movements). However, due to the differences in angulation of the maxillary incisors, the space requirement (orange) for the free movement of the mandible changes from “A” to “C.” The position to the left represents a shallow envelope of function as the envelope of function, the middle position, “B” represents a less shallow (or steeper) (or steeper) envelope of function, while position “C” depicts a restricted envelope of function. Figure 3.7 shows the same three positions of the maxillary central incisors but includes the mandibular incisors to show differences of the envelope of function movements (yellow arrow line). Position “A” represents a shallow envelope of function as there is more horizontal and vertical room to function. The positions in both “B” and “C” represent more restriction in the envelope of function as there is less horizontal space which then allows for only more vertical movements. Position “A” may represent a more normal horizontal and vertical relationship of the anterior teeth (normal overbite/overjet), while Position “C” may represent a patient with a class II, Div. II orthodontic classification or someone with a deep overbite.

3.4  Restricted Envelope of Function

a

b

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c

Fig. 3.7  Relationship of the mandibular incisor and the envelope of function with three different maxillary incisor positions illustrating the relationship

3.4  Restricted Envelope of Function One of the keys to successfully restoring anterior teeth is to understand the current relationship of the envelope of function. Creating final restorations that violate or restrict this functioning movement will ultimately lead to patients feeling uncomfortable. For example, your patient may return on multiple visits complaining that their front teeth are hitting too heavily, requiring multiple adjustments. These adjustments ultimately “shallow” the anterior guidance giving back the patient their desired envelope of function. Figure 3.8 illustrates a scenario where the restoration of the maxillary tooth is too bulky on the facial/incisal and lingual side. The illustration on the left side represents the normal relationship of the anterior teeth to the soft tissue support (lips). The upper lip covers most of the facial side of the maxillary central incisor, while the lower lip covers the incisal edge. The right side represents the larger restoration in place interacting with the soft tissue much the same way. The lips and tongue act in opposite directions to keep anterior teeth in equilibrium, also termed the neutral zone [10]. Should the neutral zone be violated then as a mechanism of compensation, the normal contraction of the lips and/or tongue will eventually correct the original violation. In our example, the crown is too bulky on the facial/incisal and lingual side. Figure 3.9 illustrates this compensation mechanism. The result of this is the rotation or change in position of the maxillary tooth. Here the change in rotation is illustrated on the right image in Fig. 3.9, marked by the purple dashed line. This small change over time results in a restricted envelope of function as illustrated in Fig. 3.10. Here the consequence of the maxillary incisor changing position limiting the horizontal freedom creates a restricted envelope of function. Other consequences of this can result in wear of the anterior teeth. In

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Fig. 3.8  Relationship of the soft tissue to the anterior teeth. Anterior restoration is too thick (example)

Fig. 3.9  Effects of increased lip contraction on the thicker restoration causing a change or restriction in the envelope of function

Chap. 6, Fig. 3.11, we made reference to the results of worn anterior teeth. Here, worn teeth will erupt to establish and maintain function, and as a result the envelope of function continues to become more restricted. This cycle of wear and eruption

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Fig. 3.10  Impact of the upper lip on the maxillary restoration that is too bulky (facial side) leading to restriction on the envelope of function

Fig. 3.11  Comparison of changes in the envelope of function

can go on for years unless a well-trained dentist can identify the problem and help the patient to take appropriate steps in solving the problem. The cycle of wear and eruption cannot be over emphasized to the reader. The earlier the problem is observed and diagnosed, the more conservative treatment will solve the problems. The other dilemma is that this type of occlusal disease usually

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Fig. 3.12  Patient example showing the smile view and retracted closed view. This patient does have a restricted envelope of function

Fig. 3.13  Patient example showing the occlusal views of both maxillary and mandibular arches

goes without symptoms unless a sign leads to symptoms, (i.e.; like a fractured tooth) Figure 3.12 illustrates a patient example of the smile and retracted view. The illustrations for this patient are in black and white to focus on the problem at hand and not focus on the aesthetic issues. Figure 3.13 now illustrates the occlusal views, where you can see the destruction of the lower anterior teeth. A better view of this destruction is featured in Fig. 3.14 where it is more apparent that the mandibular central and lateral incisors have been damaged the most. To understand the etiology of the

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Fig. 3.14  Patient example showing retracted open views illustrating the restricted envelope of function. Note the severe wear of the lower anterior teeth

Fig. 3.15 Mounted models in centric relation of the same patient example

patient’s condition, we must examine the opposing dentition. If we review Fig. 3.13, the maxillary anterior teeth have been restored with crowns. A closer look reveals that the lingual surface of these crowns was restored with metal. Figure 3.15 illustrates the mounted models in centric relation. Here, when the teeth are occluding, the anterior segment appears to show a deep bite. In Fig. 3.16, teeth #1.2 (#7) through #1.6 (#3) were removed to illustrate the coronal view of the maxillary central incisor. Here the lingual side of the maxillary restoration has no anatomical contour and is shaped much like a straight line. This does not in any way resemble the ideal lingual contours of this tooth but creates a steep anterior guidance. As a result, the lack of contour has created a restricted envelope of function. Over the decades, this patient had compensated for this restriction by trying to change or relieve this restriction in the envelope of function. As a result, the mandibular teeth have severely worn over time. Figure 3.16 clearly shows that the incisal facial contour of the lower anterior teeth matches the lingual steepness of the maxillary teeth. Surprisingly, this patient is asymptomatic which clearly shows that adaptation over a long period of time may not cause acute pain. I am certain, that had the lingual surface of maxillary restorations been contoured more like natural teeth, the patient may have had a different result.

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Fig. 3.16  Mounted models of the same patient example with the maxillary posterior teeth removed to show the relationship of the lingual side of the maxillary central incisor and the facial side of the mandibular central incisor

3.5  Verifying Envelope of Function/Technique Taking this into consideration, the question is how can you predictably create the correct envelope of function? There is a way, and it begins with the process of complete dentistry. In Chap. 4, the 12 steps were discussed in great detail to obtain the information needed to determine whether your patient had a stable or unstable masticatory system. Figure  3.17 outlines the process of complete dentistry from the initial examination to final treatment. Upon completion of the comprehensive examination and the treatment planning process, moving towards definitive treatment can only take place when your patient accepts the proposed treatment. Once accepted, the meticulous work you have completed using the semi-adjustable articulator provides your best guess on how the results of the treatment plan. The provisional (restoration) phase is a short period of time and allows the patient to evaluate and provide feedback so that alterations can be completed. The approved provisional stage requires the approval of both the dentist and your patient in three areas: 1) aesthetics, 2) phonetics, and 3) function (see Fig. 3.18). The ideal envelope of function is a result of correctly contouring the anterior teeth (incisal edge, and lingual contours) so that there is comfort in both function and phonetics. It is important to remember that this is the opportunity to work out the envelope of function and avoid leaving your patient with a restricted one. For example, unintentionally creating a restricted evelope of function with provisional restorations, your patient will return complaining of only the anterior teeth touching, or the bite feeling “tight.” Correcting this will be discussed further ahead. Verifying aesthetics is simply correcting any areas of asymmetry, more importantly confirming the position (horizontal and vertical) of the maxillary incisal edge. Figure 3.19 illustrates the three photos (“E Smile,”

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Fig. 3.17  The verification of the envelope of function occurs within the four stages of complete dentistry with the approval of the provisional restorations

Fig. 3.18  Verification to the envelope of function needs confirmation with aesthetics, phonetics, and function

“Repose,” and “Tip Down”) used to help evaluate and confirm the incisal edge position. An incorrect incisal edge will most certainly affect the aesthetics, phonetics, and function. Once the incisal edge is confirmed, begin to check the occlusion. The requirement for an ideal occlusal scheme is to have equal intensity contacts on all teeth in centric relation and the need for anterior guidance (disclusion of posterior teeth during excursive movements). This guidance should be smooth and effortless by the patient—this is a very important observation that needs to be taken seriously. Should you leave a patient that has to struggle with excursive movements, then you are setting up occlusal problems without even knowing. Figure  3.20 illustrates a

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Fig. 3.19  Patient example with verification of the aesthetics with “smile,” “tip down,” and “repose” photographs

Fig. 3.20  Patient example with verification of the function with centric contacts and excursive guidance

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case in provisional restorations of a balanced occlusion of contacts and guidance (red marks). Once you have completed the occlusion checks, a great way to verify any interference with the envelope of function is to have the patient sit upright and lean forward. Take red ribbon paper and have the patient open and close as if they were biting into an apple. Figure 3.21 shows such interferences on the maxillary central incisors (outlined in yellow). Remove this interference and recheck. The phonetics will be the last item that needs verification. There are three areas of phonetics that will be tested (this will be discussed in more detail in Chap. 7), that is the pronunciation of “F” (51–55), “T” (31–35), and “S” (61–66) sounds. If there is not any crisp, clean enunciation, the contours will need to be modified to correct the phonetics. Figures 3.22, 3.23, and 3.24 illustrate how the sounds are created. It is no surprise that when you confirm the first two elements (aesthetics and function) of provisional restorations, the last element phonetics works out on its own where there is rarely a need to make further adjustments. Finally, when all aspects are verified and the patient is comfortable, it is now time to communicate the design and contours that have been worked out. Impressions are taken of the provisional restorations, mounted in centric relation. Silicon putty is used to create a guide table that duplicates the lingual contours. Figure 3.25 illustrates the incisal pin being used to create a pattern in the silicon putty during excursive movements (R & L working and protrusive). The lingual contour is accurately represented from the centric stop

Fig. 3.21  Patient example illustrating interference with envelope of function. This patient chewed in the upright position. Lingual side of the maxillary central incisors exhibits interference (“red”)

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Fig. 3.22  Verification of the envelope of function with phonetics—“F” and “V” sounds related to correct incisal edge position

Fig. 3.23  Verification of the envelope of function with phonetics—“T” and “D” sounds related to the contour of the lingual cingulum

to the incisal edge position as illustrated in Fig. 3.26. This guide table is used by the laboratory technician to create restorations that duplicate the envelope of function, incisal edge position, and aesthetics [11, 1]. The significance of these functioning movements coincides with the lingual contours of the maxillary central incisors. This simply means when designing the lingual contours of the anterior restorations, there needs to be a clinical method of

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Fig. 3.24  Verification of the envelope of function with phonetics—“S” sounds related to the lingual contour from the centric contact point to the incisal edge

Fig. 3.25  Patient example of mounted approved provisional models and recording the envelope of function with silicon putty

validating this contour. Chapter 10 outlines the methods of preparation, planning, and quality control. As part of this process, these contours are best worked out using study models that are mounted in centric relation using a semi-adjustable articulator. Here, the occlusion and lingual contours are worked out to provide the best estimated guess. From here, this is transferred to the patient’s dentition (through restorative correction or recontouring). Once the occlusion is established (centric

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Fig. 3.26  Silicon putty index showing correlation between the centric stop to the incisal edge (this is the ideal lingual contour of the maxillary central incisor)

stops on all anterior and posterior teeth), the next step is to confirm the function, aesthetics, and phonetics. To confirm the function, we must include anterior guidance and the envelope of function. Here, the lingual contours are confirmed with the mandible moving in two directions: “Inside out” and the reverse “outside in.” The former direction is confirming that the lingual surfaces of the maxillary anterior teeth cause the mandible to disclude the posterior teeth during excursive movements. It is important to note that just about any contour can separate during protrusive movements, but the key is to make sure that the movement is smooth, consistent, and almost effortless. Pay attention to the manner at which the patient moves from the centric stop until the lower mandibular incisors are edge to edge with the maxillary incisal edge. If you notice some resistance or the marking of the articulating paper is very wide and heavy, then the lingual surface of the maxillary central incisors is too steep. Shallowing the contours will eventually produce a desired result as described earlier. The latter direction is confirmed by having the patient sit upright. With articulating paper resting in the anterior teeth area, ask your patient to open and close as if they are chewing. If the paper produces interferences on or near the same marks as the protrusive ones, then more adjusting (of the lingual contour) is required to improve or shallow the envelope of function. During the treatment planning process, if anterior restorations are required to correct or improve the occlusion (or function), then the confirmed contours of the anterior provisional restorations

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will need to be clearly communicated to the dental laboratory technician. This is discussed in much more detail in Chap. 10.

References 1. Dawson PE (2007) Functional occlusion: from TMJ to smile design. Mosby Elsevier, St. Louis, MO 2. Thornton LJ (1990) Anterior guidance: Group function/canine guidance. A literature review. J Prosthet Dent 64 (4):479–482 3. Graf H, Zander HA (1963) Tooth contact patterns in mastication. J Prosthet Dent 13(6):1055–1066 4. Stuart D (1927) Some aspects of the innervation of teeth. Proc R Soc Med 20:1625. 5. Posselt U (1957) Movement areas of the mandible. J Prosthet Dent 7(3):375–385 6. Waysenson B, Salomon J (1977) Three-dimensional recordings of envelopes of motion related to mandibular movements. J Prosthet Dent 38(1):52–60. https://doi. org/10.1016/0022-3913(77)90266-9 7. Klineberg I (1980) Influences of temporomandibular articular mechanoreceptors on functional jaw movements. J Oral Rehabil 7(4):307–317. https://doi.org/10.1111/j.1365-2842.1980. tb00449 8. Wirth CG, Lundeen HC, Gibbs CH, Mahan PE, Zunka CA, Wilkins JS (1976) Chewing and superior border movements measured at the mandibular condyles. J Prosthet Dent 55:B102 9. Gillings BRD, Graham CH, Duckmanton NA (1973) Jaw movements in young adult men during chewing. J Prosthet Dent 29(6):616–627 10. Cagna DR, Massad JJ, Schiesser J (2009) The neutral zone revisited: from historical concepts to modern application. J Prosthet Dent 101(6):405–412. https://doi.org/10.1016/ S0022-3913(09)60087-1 11. Alpert RL (1996) A method to record optimum anterior guidance for restorative dental treatment. J Prosthet Dent 76(5):546–549. https://doi.org/10.1016/S0022-3913(96)90016-5

4

The Complete Examination: The 12 Steps Needed to Perform a Complete Exam

“A pessimist sees the difficulty in every opportunity; An optimist sees the opportunity in every difficulty.” Winston Churchill

Contents 4.1  Discussion 4.2  New Patient Interview 4.3  Patient Office Tour 4.4  TMJ Examination 4.5  Muscle Palpation 4.6  Occlusion 4.7  Oral Cancer Screening 4.8  Hard/Soft Tissue 4.9  Intraoral Images 4.10  Periodontal Probing 4.11  Appropriate Radiographs References

4.1

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Discussion

The complete examination is by far the most underrated and overlooked procedure in dentistry. Throughout the last several decades, dentistry has evolved through advances in technology, materials, and techniques. These advances are primarily beneficial to both the dentist and patient. However, they are limited to clinical procedures that involve restoring teeth and/or treating periodontal disease. Regardless of the advances mentioned above, the fundamentals of performing a complete examination have been underestimated. I can also attest to this fact in my own practice.

© Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_4

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Before I began this journey, my examinations were approximately 10 min in duration, and were only completed after the patient had radiographs and professional cleaning completed by the hygienist. The focus of this examination was primarily based on observing bacteria associated with dental decay and periodontal disease. As a result, treatment plans were created based on issues related to both bacteria (dental decay and periodontal disease) and tooth structure (open margins, cracks, etc.). Dr. Peter Dawson has termed this practice of dentistry as “tooth by tooth” [1]. In other words, all the focus is only on just repairing compromised teeth, and nothing else. As mentioned above, the comprehensive examination is the most understated procedure performed by dentists. The speed at which exams are done today cannot provide the dentist with enough information needed to understand and comprehend their patient’s occlusion and function. This lack of information will lead to unpredictable, and less conservative treatment. It is my opinion that the reason why treatment fails is due to the fact that the providing dentist overlooked something that was relevant pertaining to the patient’s masticatory system. A systematic approach consisting of 12 steps is needed to fully comprehend a patient’s masticatory system [2, 3]. The first 10 steps are designed for you (and your team) to build rapport with your patient and formulate a diagnosis (both functional and structural). Today, the examination in my practice is approximately 60 min in duration which includes 10 of the 12 steps. The final two steps (11 and 12) include diagnostic records saved for the diagnostic analysis. This new or comprehensive examination would be the equivalent of a full physical performed by a medical docto. In Chap. 8 we discuss the differences in procedures in how a dentist and a physician arrive at a diagnosis. When performing an assessment, a medical physician would not order any type of radiographs, diagnostic tests, or blood work without performing a complete examination or assessment. It is the physician’s discretion to prescribe more tests to get a better understanding of the patient’s condition(s), and to arrive at a diagnosis and eventual treatment. As a dental profession, we are the experts in this region called the masticatory system. One way to truly understand and appreciate your patient’s masticatory system is to perform a “full physical” on the masticatory system. Much like the physician model, gathering the correct information will allow you to determine whether more diagnostic information is required to properly diagnose your patients. This “full physical” is the complete dental examination of the patient’s masticatory system, which comprises 12 steps [2, 3]. Figure 4.1 illustrates a flowchart of steps 3–10. Since this type of examination is usually performed on a new patient (and sometimes existing patients), we can refer to this as the new patient experience. An experience throughout the entire process of the examination. This process and experience must be like no other, and the goal is for your patient to be impressed with the detail and thoroughness and be able to say, “I have never had and examination like that before!” We will dive deeper into the “new patient experience” and explain the relevance of each step. The following are the 12 steps: 1. New patient interview 2. Patient office tour 3. TMJ examination 4. Range of motion (ROM)

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Fig. 4.1 The comprehensive examination process, steps 3–10. Structural and functional diagnosis

5. Centric relation 6. Muscle palpation 7. Soft/hard tissue 8. Intraoral images 9. Periodontal probing 10. Appropriate radiographs 11. Diagnostic records 12. Digital photography

4.2

New Patient Interview

We begin the process with an interview with our new patient. This should be done in a private area such as a consultation room or a private office. The reason for this is to find a setting that is neutral which will allow the patient to feel at ease. This creates an opportunity for the dentist to meet with the patient and begin an open dialogue. Sometimes patients have emotional barriers that prevent them from opening up and as a result become more difficult for the dentist and team to connect with the patient. The goal here is to achieve the following: 1 . Build rapport, and inquire about patients’ priorities, needs, and desires. 2. Discuss past dental experiences. 3. Inquire about what the patient knows about their oral health. 4. Inquire about patient expectations. 5. Educate patient on normal dental health, and your philosophy. 6. Inform patient on the expectations of the examination co-discovery. 7. Learn something personal about your patient (family, job, kids, hobbies).

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4.2.1 Build Rapport Building rapport with a new patient is by far one of the most important skill needed. One of the easiest ways to start is to review the completed patient forms before meeting your patient. In most cases, there is valuable information or clues to use that make it easier to build a rapport. Having one of your designated team members review the patient information prior to the patient arriving is helpful. Building rapport can be as simple as finding something in common with your patient. For example, a mutual patient, personal interests, and common place of residence are great topics to create rapport. If a new patient was referred by another existing patient, start discussing the connection between the new patient and the referring patient. An example of a great question to ask is “Tell me how you and Mrs. Smith know each other” or “We are so happy that Mrs. Smith referred you to us, and I will personally thank her. Tell me more about your connection with her.” On the other hand, if a new patient was not referred to your office by other means (internet, etc.) then building rapport is done differently. In this case since you have already reviewed the patient information with your team member, a good way to build rapport is to acknowledge the source and find out more on why they chose your office as opposed to other choices. An example statement of this would be “I understand that you found our office on the Internet (whatever search engine they used). Please tell me why you chose us?” Once this information is known, acknowledge it and thank the patient for choosing your office. The next step is to inquire more about your new patient with respect to their priorities, needs, and desires. This is important to know up front because our patients today most likely have completed their own research on certain procedures, especially aesthetic treatment. Because of this, they have already formulated opinions and/or feelings about specific procedures. Without knowing how your patient feels about a procedure, what you may say can backfire or go against their comfort level—this will not give you the opportunity to build rapport, but only diminish your chances.

4.2.2 Past Dental Experiences Surprisingly, many dentists do not ask new patients about their past dental experiences unless the patient takes the initiative first. It is an opportunity for the dentist to understand the patients psyche with respect to previous treatments, expectations, and emotional well-being. Even more important is the past relationship of the new patient with the previous dentist. This knowledge will give you insight into what made or broke the relationship and how this can help you take the opportunity and make it better for you and your new patient. In order to begin this conversation, it can be helpful to ask open-ended questions. For example, “Tell me more about your last experience with the previous dentist?” or “What are some of the things you did not like about your last experience?” or “What can we do here to make your experience more comfortable?” The next step is to let your new patient speak with no interruptions. I have noticed a pattern where dentists far too many times do not allow the patient to speak without interrupting them. This sometimes can be distracting for the patient as any interruption may change the focus of their thoughts.

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This can prevent the dentist from gathering relevant information that could have allowed you to understand your patient’s mindset, and perspective.

4.2.3 I nquire About What the Patient Knows About Their Oral Health This part of the new patient interview involves asking the patient what they know about their oral health. This is an easy subject because most patients have some idea of why they are in your office. An example of a question that you may ask is “Tell me what you know about your mouth?” They may start with some basic information, but it is up to the dentist to dig deeper by simply saying, “Tell me more about this.” You would be surprised how much more information your patient will provide once you give them an opportunity to share this information. It is valuable as you can gauge their understanding and perception of what they know. In addition, it can give you an opportunity to perhaps fill in the voids that may be missed by the patient during the “Building Rapport” segment of the interview. This segment of the interview will also tell you whether your patient has any opinions regarding certain procedures. Usually, patients will conduct their own research on a particular treatment or problems, and form their own opinions. This information can be from other people they know or in most cases by themselves browsing the internet. It is important to understand their feelings, even if you do not agree. Should you experience such situation, remember to acknowledge the patients’ feelings and attempt to connect their understanding to your professional opinion. If you fall into the trap of objecting to the patients’ own opinions, then you will most likely run the risk of struggling to build rapport. For example, if your patient states that they would like veneers, then you must inquire as to why they feel that this is a valid treatment option. We will discuss this subject of communication in Chap. 9. Remember to always make the connection with what the patient states and the information you provide.

4.2.4 Inquire About Patient Expectations Part of the success of any treatment no matter how simple or complex is meeting the patient’s expectations. Part of this interview is the most opportunistic time to inquire and understand the patient’s expectations. These can be subdivided into two parts: 1. Patient desires/wants 2. Patient costs A patient’s desires or wants can comprise a change in appearance or a once healthy procedure that they are interested in. This does not have to be aesthetically motivated, but it may be related to a procedure that either gets them out of pain or addresses an issue that has failed. Either way, we need to understand our patient’s desires from both the physical and emotional levels. These desires can stem from a friend, family member, or inspired by a celebrity or someone important. It is important to understand why they seek it and how important it is to them to achieve it. Remember to always

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acknowledge the patient’s desires and let them know that you are going to pay attention and do the very best to meet or exceed those expectations (within reason). Another reason to fully understand the patient’s desires is to use this as a future reference during a treatment planning consultation. Bringing this information on the table again reaffirms your commitment to the patient on addressing their desires and wants. Dental costs are probably one of the most important factors in determining whether a patient moves forward with treatment. To avoid situations where the patients are later overwhelmed about fees, it may be a good idea to have this conversation at this time. It is not recommended to go into details about fees since the treatment plan has not been formally presented. However, it is a good idea to at least find out if your patient has an idea of what to expect to pay for a certain procedure. For example, if your patient thinks that porcelain veneers are a solution to improve an aesthetic concern, then it is fair to ask “Do you know what the cost of a veneer is?” or “How much do you think it would cost to place a veneer?” To take it one step further, it also helps to simply ask “What is your planned budget for this procedure?” Either way you will get a good idea whether the patient is realistic from a financial stand perspective. When you understand your patient’s response to any of the above questions, it will give you a better idea of your patient’s financial boundaries, and whether you need to consider other options due to cost. The goal is to create realistic expectations from both clinical and financial parts for your patient.

4.2.5 E  ducate Patient on Normal Dental Health, and Your Philosophy Like most patients that visit their respective physicians, they have some idea of normal health conditions, for example hypertension. Most patients understand what systolic and diastolic numbers constitute hypertension, and the long-term effects of not treating it. As a result, patients are open to remedies that may include diet changes and/or prescriptions to manage this condition. The same applies to our profession; however it is limited to decay, pain, and bleeding gingival tissues. From my experience of speaking to so many patients during the initial interview, a vast majority have a limited understanding of what normal dental health is. Surprisingly, many patients report of not ever having their gingival pockets measured! Nevertheless, this is where the opportunity lies in educating your patient with a summary of what is considered normal dental health in three areas. 1. Bacteria: These are responsible for dental decay and periodontal diseases. Most patients can easily relate to bacteria causing tooth decay and others are not aware of the importance and connection of periodontal disease and systemic health. It is important to make the patient aware of how you will diagnose their periodontal status (probing, bleeding sites, FMX). More importantly, if changes are going to be made in the dentition, then it is just as important for the patient to know that oral hygiene is paramount. This is the foundation that will support any restorative treatment and needs to be assessed before any final treatment is completed. 2. Structure: Signs of instability include cracks and wear. An explanation of these signs is important for the patient to understand. Patients must know that enamel

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is the hardest structure in the body, and when it has worn down, cracked, and/or fractured, it is vital to explain that this is not normal and can only occur from either excess forces (mechanical) or acid (diet, GERD, etc.). Most patients have signs of instability and either are not aware or were told (by other dentists) that the structural signs are due to aging, etc. Remember that most patients in general do not associate a sign with disease until it becomes a disability. Because of the lack of awareness and symptoms, you must be proactive in educating your patient so that when time comes to do the examination, your patient is aware of what you are looking for. There are no surprises and your patient will not be so reluctant in questioning your intentions. 3 . Function: Temporomandibular joint, muscles of mastication, and occlusion: This is probably the most overlooked aspect of why patients may become disconnected. This is not well understood because most dentists have not done a better job of educating themselves on understanding the importance of function. It is important to explain how you are going to examine the temporomandibular joints, muscles of mastication, and occlusion. More importantly, this is the opportunity to help your patient know that all of these three areas of function are connected to each other. In addition, making any changes to the teeth (restoratively and/or orthodontically) must be comfortably accepted by the muscles of mastication and the temporomandibular joint. This information can be delivered in several ways. One method is to create a power point presentation illustrating examples of normal and/or abnormal health. After explaining this to your patient, it would be time to share your experiences with other patients who have gone through the same process. In addition, you have to express why you think this is so important and why you have chosen to treat every patient in a similar way. For me this has led to predictability with long-lasting results that make my patients very comfortable. Share your reasons honestly and with humility. Your patients will see it and more importantly feel it.

4.2.6 I nform Patient on the Expectations of the Examination Co-discovery To elaborate further on what was mentioned in the previous paragraph, the goal for you is to make sure that you have explained this process of how bacteria, structure, and function are connected with the complete oral health of your patient. In addition, inform the patient that this complete examination will be a co-discovery one. That is, both the dentist and the patient are going to learn much about these three elements of dental health. In addition, there may be conditions that may come up in the examination that were not initially discussed by the patient. At this point, state this openly such as “During the examination, if I find conditions other than what you mentioned, do I have your permission to discuss this with you? and find out if this is important to you.” In most cases your patient will not object to this since you are being open and preparing the patient ahead of the examination. This will give you permission to complete your examination without feeling any concerns about how the patient may perceive your findings during the examination. There is

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nothing worse than to overwhelm a new patient with findings that they were not expecting nor perceived as important. The value of the co-discovery examination is to keep the patient engaged during the entire exam. As you will see later in this chapter, each part of the examination will involve the patient either giving feedback or simply informing them of a condition and asking whether this is important to them. Remember, the comprehensive examination gathers clues and facts on the patients’ condition(s). It is the responsibility of the dentist to put these facts together in a manner that allows the patient to not only understand their problems, but remain open to discussing solutions as well.

4.2.7 L  earn Something Personal About Your Patient (Family, Job, Kids, Hobbies) I recommend this be done at the end of the new patient interview. You have gathered information about your patient, and discussed clinical norms in dental health and expectations. To close the interview, it is nice to inquire more about the person sitting across the table who is about to take an important step in trusting and putting care in your hands. Simply ask “Tell me more about your work and your family” or “What are your hobbies in your spare time?” This gives the patient a tremendous amount of comfort that you are interested in knowing them in a personal way. Remember, this must be done with genuine feeling and respect, and not in a way that seems a chore for you to ask. If the patient does open up about a specific subject or experience, then share something about you that makes a connection on a similar or same subject. People feel more connected when they have something in common, and the bond that is created in the interview process is a great start in developing trust, respect, and motivation. The ideal place to complete the interview is in a consultation room. This area is usually private and conversations can be confidential. However, if you do not have a private consultation room, then find an operatory or another place that can be comfortable to have this initial conversation. Upon completion of the interview, it is time to transfer the patient from the consultation room to the operatory. The best and most convenient way is to “hand over” the patient to another team member, usually an assistant or treatment coordinator. The team member can enter the consultation room, at which a brief summary can be presented to the team member and then the handover is complete.

4.3

Patient Office Tour

This next step of the new patient experience is not clinical in nature, but a brief pause which serves as a transition from the initial interview to the treatment operatory. The tour consists of introducing the patient to other team members and showing them important aspects (restrooms, sterilization, etc.) of the office. This is important as this gives the patient a sense of comfort and familiarity, much like a guest. The transition should be rehearsed with your team to make this smooth and

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flawless. When the patient is seated in the treatment operatory, it should be clean, organized, and prepared for the examination. The patient is made comfortable, draped, and ready for the beginning of the examination.

4.4

TMJ Examination

In Chap. 2, we discussed the starting point of occlusion begins at temporomandibular joint and ends with the anterior teeth. It makes perfect sense to begin the comprehensive examination with the temporomandibular joints. It is important for the dentist to have a thorough dental history of any issues related to the temporomandibular joint, including trauma, parafunction, and pain. This information will help in making a differential diagnosis of the temporomandibular joints [4]. This joint is unique unlike other joints in the human body; it has two movements, rotation, and translation. We will review the anatomy of the temporomandibular joint to get a better understanding of the basic components. The temporomandibular joint is comprised of a mandibular condylar head that is seated into the glenoid fossa. Surrounding the condyle is cartilage, synovial fluid, and a disc (or articulating disc). Attached to the anterior segment of the disc is the superior belly of the lateral pterygoid muscle, while the posterior segment of the disc is held in place by a posterior ligament (that is connected to the posterior neck of the condyle). The inferior belly of the lateral pterygoid muscle is attached to the anterior neck of the condyle. See Fig. 4.2. The condylar head of the mandible has both medial and lateral sides. From a sagittal view, the medial side of the condylar head articulates to the narrowest part

Fig. 4.2  Illustration of the anatomy of the temporomandibular joint

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Fig. 4.3  Illustration of the mandibular condyle inside the glenoid fossa

Fig. 4.4  Coronal view of the condyles at rest and braced

of the articulating eminence, whereas the lateral side articulates to the wider part of the eminence. Figure  4.3 illustrates how the left temporomandibular joint is positioned in the glenoid fossa. In between the condylar head and the articulating eminence lies the articulating disc. This non-innervated disc extends on both medial and lateral sides of the condylar head (much like a bucket handle). From the coronal plane, the disc has a biconcave shape due to the shape of the a­ rticulating eminence and the condylar head. This shape has also been referred to as the “bow tie” and is clearly seen in an MRI image of a normal healthy temporomandibular joint. During full occlusal closer of the mandible, both the condylar head and disc are braced against the eminence. This is accomplished with the aid of the “positioner” muscles, that is, medial pterygoid, lateral pterygoid, and posterior segments of the temporalis muscle. These muscles direct the condylar head toward the medial side of the glenoid fossa. As a result, the medial side of this condylar relationship bears a great deal of more force as compared to the lateral side. Figure 4.4 is a sagittal view illustrating this point as the bracing force is directed

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Fig. 4.5  Coronal view of temporomandibular joint at rest

Fig. 4.6  Coronal view of temporomandibular joint at seated (this occurs when all the elevator muscles contract)

toward the medial side of the glenoid fossa while Figs. 4.5 and 4.6 illustrate the difference with the temporomandibular joint at rest vs. fully seated. Posterior to the disc is the retrodiscal tissue which has its own blood and nerve supply. Anteriorly, it is attached to the lateral pterygoid muscle. This muscle is made

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up of both an inferior and a superior part. The superior part is attached to the articulating disc and is responsible for keeping the articulating disc on the condylar head during rotation and translation (opening and closing of the mandible), while the inferior portion is responsible for translating the condylar head during opening and lateral or excursive movements of the mandible. For a normal health-stable joint to function, we would expect to see the patient’s mandible opening and closing without any deviation toward any side. The process of examining the TMJ can be broken down into several parts. They are as follows: 1. Joint palpation 2. Doppler auscultation 3. Range/direction of motion 4. Joint loading

4.4.1 Joint Palpation Place your index fingers slightly anterior to the tragus. While the patient is at rest (teeth are not in contact) apply slight-to-moderate pressure and ask the patient if they feel any tenderness. Document any tenderness present whether on one or both sides. Then ask the patient to fully open and continue to apply the same pressure. Again, document any tenderness. While performing this exercise please take note if you feel or notice any popping or crepitus during the opening or closing of your patient. This will give you clues as to the possible changes to the temporomandibular joint. In addition, another method of gaining more information is to place your “pinky” finger inside the ear and rest the soft part of your finger anteriorly. Then ask your patient to fully open and close. You should be able to feel the lateral side of the condyle during movement of the mandible. While the patient is fully open and the pressure of the finger elicits tenderness or discomfort, then this may be an indication that there is inflammation present in the retrodiscal tissue. Figure  4.7 shows an example of where to begin palpating the temporomandibular joint.

4.4.2 Doppler Auscultation Just as the name suggests, using ultrasound will allow you and the patient to hear and listen to joint activity during normal mandibular movements such as opening, closing, and excursive movements. A healthy joint is well lubricated and is defined as a joint that has normal range of motion and that is pain free, where the articulating disc has a stable relationship with the condylar head during all movements of the mandible. Temporomandibular joints are well lubricated, and healthy ones do not produce joint sounds. We expect a smooth transition of mandibular movements with no sounds. However, during joint degeneration, the disc assembly begins to change and subsequently joint sounds are heard. If there is friction between the bone and

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Fig. 4.7  Illustration of temporomandibular joint palpation

Fig. 4.8  Illustration of Doppler auscultation device

cartilage (articulating disc), then you will hear a grating sound also known as crepitus. As the conditions worsen, grating sounds may change to clicking or popping over time. The advantage of using the Doppler allows the clinician to understand or discern whether the suspected problem of the disc is located on the medial or lateral pole of the condylar head. Sounds from the Doppler during rotation of the condyle will indicate that the articulating disc is being affected on the medial pole. On the other hand, sounds heard during translation of the condyle will indicate that the articulating disc is affected on the lateral pole. Should you hear or suspect a medial pole problem, please consider further evaluation of the joint by requesting an MRI. The radiologist report will confirm the position of the articulating disc on both poles during opening and closing of the mandible. Figure 4.8 illustrates where the Doppler is used to listen to the temporomandibular joints.

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4.4.3 Range/Direction of Motion The purpose of this part of the TMJ examination is to evaluate the range of patient maximum movements as well to document if there is any deviation to opening and/or closing. The idea here is to find out if there is a decrease or change in the amount of functional movement. That is why the direction of the mandibular opening and closing is also an important element to document. As mentioned earlier, under normal circumstances, we expect the mandible to open in a straight direction and stop at maximum opening. The reverse is true during closure as we expect this to be also smooth and straight. It is important to note that when we witness something other than a normal opening/closing, then we must understand why and be ready to use this to identify a potential problem. For example, a patient opens their mandible and you see it deviating to the right. During the opening of the mandible, we know that both lateral pterygoid muscles contract simultaneously. However, if one side does not contract at the same pace as the other, then we will witness the mandible drift toward the deficient side. In our case example, the mandible deviated toward the right side on opening. Since we expect muscles on both sides to contract evenly, it is evident in our example that the right lateral pterygoid muscle is deficient. This delay can be attributed to either muscle fatigue or disc displacement on the right side. In this same example, the patient begins to close and we notice a deviation to the left side on closing, and eventually the patient straightens out. Again, the right lateral pterygoid muscle has not released at the same time as the left. There are many other combinations of mandibular movements during opening and closing. The main point is that this should not be overlooked as this could be something more significant. There are four movements that should be recorded: 1. 2. 3. 4.

Maximum opening Left lateral Right lateral Protrusive

The ruler ideally suited to accurately measure these movements is made by Great Lakes Orthodontics. This ruler has two sides with rulers. The curved side with the notch is designed to measure maximum opening and the narrow side measures the remaining three measurements (R and L lateral, and protrusive) (Fig. 4.9). It has been documented that the average range for a patient’s maximum opening should be somewhere between 45 and 60 mm, and lateral excursive and protrusive movements between 8 and 12 mm [5]. Please remember to take into consideration the patient’s overbite when measuring this range. With the patient slightly opens, first place the notch of the ruler on the lower incisal edge. While the patient opens fully the opposite end will measure the amount of opening. Once recorded, measure the existing overbite and add this to what was measured from the ruler. This must be done as the overbite must be cleared first before the rest of the opening takes place. For example, Fig. 4.10 illustrates that the overbite of a patient is 3 mm, and the measured opening is 52 mm. The maximum opening is 55 mm. When measuring both right and left lateral movements, place the narrow part of the ruler’s midline parallel to the lower incisor midline (see Fig. 4.11). Please be sure not to use the patient’s facial

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Fig. 4.9  Ruler used to measure maximum opening, and excursive movements. (Courtesy: Great Lakes Orthodontics Ltd., Tonawanda, NY)

a

b

Fig. 4.10  Patient example of measuring maximum opening and taking overbite into consideration Fig. 4.11  Placement of ruler is in relation to the mandibular midline. Here the patient mandibular dental midline is slightly to the right of the maxillary one

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midline to measure the lateral movements. If the patient’s lower dental midline is different from facial one, then this will produce a larger number toward the side of the deviated dental midline, and conversely will produce a much smaller number toward the opposite side of the deviated midline. Figures 4.12 and 4.13 illustrate that the left and right excursive measurement is approximately 11  and 12  mm, respectively. Finally, measuring of the protrusive movement is done by asking the patient to protrude as far as possible. Place the ruler perpendicular to the upper incisal edge and measure till where the lower incisal edge stops. Similar to the maximum opening measurement, we must also take into consideration the patient’s overjet. In order for the lower incisal edges to protrude past the upper central incisor they have to clear the existing overjet. For example, Fig. 4.14 illustrates that the protrusive measurement is 5 mm (front upper incisal edge to lower incisal edge) and the overjet is 2 mm, with the total protrusive distance of 7 mm. If you experience a limited movement (less than normal) in any of the documented movements (Figs. 4.12, 4.13, and 4.14), then suspect muscle fatigue/spasm and/or TMJ issues. This can be confirmed in the later steps in the complete examination.

Fig. 4.12  Measuring the left lateral movement

Fig. 4.13  Measuring the right lateral movement

4.4 TMJ Examination

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b

Fig. 4.14  Measuring the protrusive movement and taking the overjet into consideration

4.4.4 Joint Loading An orthopedic surgeon would assess any human joint whether it be a shoulder or a knee by applying pressure directly to the respective joint. This pressure is also termed “loading” the respective joint for diagnostic purposes, that is, to determine the health of the joint. Similarly, the temporomandibular joint can also be loaded for the same reasons. Loading the temporomandibular joint is simply a diagnostic exercise used to access the stability of the patient’s temporomandibular joint. Joint loading is described as seating both condyles in its respective anatomical position (articular eminence), using a technique called “bimanual manipulation” [1]. As the name implies, this technique requires the use of both hands of the dentist to seat both condyles in the glenoid fossa. When done correctly, this technique produces repeated results that are precise and accurate. The repeatability of this technique provides grounds to understand that the starting point of occlusion begins here. The relationship of the joint position and how the teeth articulate together forms the foundation of a stable occlusion. This joint position is known or defined as centric relation. That is, when both the elevator and positioner muscles fully contract, the condylar-disc assembly is braced in the glenoid fossa and takes the most superior anterior position in the glenoid fossa (see Fig. 4.15). There is much controversy related to this term and some have dismissed the importance of this joint position. It is important to remember that this definition is only true if the articulating disc is fully seated on the condylar head. The purpose of using “bimanual manipulation” in joint loading provides two important clinical assessments. First, this technique ­confirms the health of the TMJ by achieving centric relation without symptoms. In other words, can the temporomandibular joint handle firm loading in centric relation asymptomatically? Symptoms associated with loading the joint can come from two sources, muscle or intracapsular. Seating the joints in the glenoid fossa may result in some resistance from the lateral pterygoid muscle and your patient may describe this

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4  The Complete Examination: The 12 Steps Needed to Perform a Complete Exam

Fig. 4.15  Centric relation—the relationship of the condyle, disc, and eminence

as “tension” or a “tightness” near the temporomandibular joint. This is not to be mistaken for a sign of discomfort, but an indication that the lateral pterygoid muscle has not released, preventing the condyles to be seated in centric relation. On the other hand, symptoms associated with intracapsular issues may present as actual discomfort by the patient and may indicate that there is in fact a joint problem resulting from trauma or inflammation associated within the capsule of the ­ temporomandibular joint. The ­second important assessment in using bimanual manipulation is that it provides information related to any deflective interferences when the teeth are brought together. As you will learn later, one of the requirements for a stable occlusion is to have equal contacts of all teeth (anterior and posterior) while the joints are in centric relation. While in centric relation, any deflective interference(s) found when the teeth are brought together will cause the mandible to shift (usually forward) in an attempt to avoid the deflective interference. The process of using bimanual manipulation begins with the patient reclined in the treating position. The patient is asked to tilt their head upwards, and then to open the mandible enough to slightly hinge. Begin with the hands correctly positioned as the fingers are seated on the mandible while the “pinky” finger is just behind the angle of the ramus. Following this, the thumbs are positioned just above the “chin” at the symphysis of the mandible. Both Figs. 4.16 and 4.17 illustrate the location of where the finger and thumb position on the skull model, while Fig. 4.18 illustrates the same on the patient. Incremental loading begins usually in three loads—light, medium, and firm. In between each load, we need to ask our patient whether they feel any tension (muscles) or tenderness (joint) [1]. As long as our patient does not feel any tension nor tenderness, we have permission to increase loading to the next level. Figure 4.19 illustrates the incremental loading using bimanual manipulation. The goal is to verify

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Fig. 4.16 Bimanual manipulation technique illustrating the finger position relative to mandible

Fig. 4.17  Bimanual manipulation technique illustrating hand, finger, and thumb position on the mandible

centric while identifying any issues that may result in tension or tenderness. Tension (or “tightness as described by patients) is related to muscle—specifically the lateral pterygoid (inferior portion). In order for loading of the joints to be successful, the lateral pterygoid muscle needs to be released or relaxed. A relaxed lateral pterygoid will allow the condyles to seat comfortably. However, some patients may feel tension on either one side or both sides. Regardless, centric relation cannot be confirmed and the goal then is to find a way to relax the lateral pterygoid muscle. Deprograming the lateral pterygoid muscle can be accomplished using cotton rolls or an anterior jig deprogrammer (see Fig. 4.20—anterior Denar® Deprogrammer). Both of these methods will separate the back molars and over time (several minutes) deprogram the lateral

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Fig. 4.18  Bimanual manipulation technique illustrating hand, finger, and thumb position on a patient example

Fig. 4.19  Bimanual manipulation technique illustrating incremental loading of the temporomandibular joints Fig. 4.20  Illustration of anterior deprogrammer in a patient. (Denar® Deprogrammer, courtesy of Whip Mix Corporation)

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Fig. 4.21  Flowchart leading to verification of centric relation

pterygoid muscle(s). After deprogramming is complete, a second attempt at loading the joints may lead to a confirmation of centric relation and confirm that the lateral pterygoid was in fact deprogrammed. This can occur at any “load” interval and discipline is paramount not to proceed to the next load level unless the patient has verified to the dentist that there is no “tension” or “tenderness.” Figure 4.21 illustrates the flowchart of verifying centric relation using the incremental load technique of bimanual manipulation. Remember, in order to verify centric relation, the temporomandibular joints must accept firm loading (“load 3”) with no tension (muscle) or tenderness (intracapsular pain) on either side. Should your patient experience either sign, the appropriate measure of either deprogramming or splint therapy is required. As mentioned earlier, deprogramming may take a few minutes or hours, depending on the degree of tension of the lateral pterygoid muscle. As Fig. 4.21 illustrates, upon completion of deprogramming, you must start at the beginning with “load 1” and then continue down the flowchart until you can confirm centric relation. Tenderness is a sign related to the joint itself, not muscle. If your patient indicates that they feel tenderness, then that is related to TM joint pain. At this point, suspect some intracapsular changes that may lead to inflammation (retrodiscal tissue)—centric relation cannot be confirmed and the joint condition needs to be treated first. Since this chapter is focused on the examination, details on how to treat TM joints will be discussed at a later time. Remember, a healthy joint is one that can accept firm loading without any tension or tenderness. Once you have established that both left and right TM joints can accept full loading, the next step is to ask the patient to begin to close while you are loading the joints. At this point we are looking for the initial point of contact and will ask the patient to identify it by pointing to the area. Once you have established that there is a deflective interference, then ask the patient to close or squeeze their teeth together. You will then notice the mandible shift or slide to bring all the teeth together. The distance travelled from the initial

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Fig. 4.22  Patient example of difference in the mandibular movement from centric relation (first point of contact) to maximum intercuspation

Fig. 4.23  Same patient example with restorative treatment completed in centric relation

point of contact to full closure is the difference between centric relation and maximum intercuspation. It is always a good idea to repeat this process so that you are consistently getting the same recordings. In the vast majority of patients that exhibit a deflective interference in centric relation, the slide into maximum intercuspation is always anterior. This means the lateral pterygoid muscle is constantly active to keep the mandible in the MI position. Thus, you ultimately will have the positioner and elevator muscles working simultaneously to keep the mandible in place. Figure 4.22 illustrates a patient with load 3  in centric relation. Note how the anterior teeth are not in contact in centric relation, but in maximum intercuspation, the mandible has advanced so far forward that the patient’s anterior teeth are in an edge-to-edge position. This patient was restored in centric relation, with a perfected occlusion and is illustrated in Fig. 4.23.

4.5 Muscle Palpation

4.5

77

Muscle Palpation

Once you have completed the temporomandibular joint examination, the next step is to determine if the muscles have a relationship to any possible discrepancies related to the TMJ examination. The goal is to have a stable occlusion with muscles of mastication that are comfortable [1, 6]. Usually, when there are deflective interferences in the occlusion (from centric relation to maximum intercuspation), it is not uncommon to find some muscles of mastication that exhibit discomfort. There are several muscles that allow the mandible to open and close. The muscles of mastication are responsible for opening, closing, and eccentric movements of the mandible. Opening movements of the mandible are controlled by the digastric muscle (anterior and posterior), also called the depressor muscles—see Fig. 4.24 outlining the depressor muscles. Closing occurs with the aid of the temporalis (anterior and middle segments), masseter, and deep masseter muscles, also called the elevator muscles—Fig. 4.25 illustrates the elevator muscles. The remaining muscles (medial pterygoid muscles, lateral pterygoid muscles, and posterior segment of the temporalis) are referred to the positioner muscles as they are responsible for positioning the mandibular condyle to the correct position in the glenoid fossa. Figure  4.26 illustrates these muscles. These muscles will play a part of our comprehensive examination later in this chapter. For example, if the mandible deviates to one side or if the joints are not verified due to tension felt by your patient, then we may expect to find some muscles to be affected. Specifically, the muscles of mastication will be the ones to examine closely. They are separated into three groups, those that close∗ and open the mandible∗∗, and

Fig. 4.24  Mastication-depressor muscles including both posterior and anterior digastric

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4  The Complete Examination: The 12 Steps Needed to Perform a Complete Exam

Fig. 4.25  Mastication-elevator muscles including temporalis, masseter, and deep masseter

Fig. 4.26  Mastication-positioner muscles including posterior temporalis, medial, and lateral pterygoid

supplementary ones∗∗∗. The supplementary ones are not related to function, but are important to note since they can be related to other issues like headaches or referred pain. They are the following: 1. Sternocleidomastoid∗∗∗ 2 . Digastric (posterior and anterior)∗

4.5 Muscle Palpation

3. 4. 5. 6. 7. 8. 9.

79

Superficial masseter∗ Deep masseter Temporalis∗ Posterior neck∗∗∗ Trapezius∗∗∗ Medial pterygoid∗ Lateral pterygoid∗∗

The technique of palpating muscles involves using your fingers to isolate them while palpating with firm pressure. If light or heavy pressure is used, then be prepared to either collect too little or false-positive data from your patient. Prior to this examination it will be helpful to ask your patient to measure the amount of tenderness (if any) on a scale from “0” to “3.” • • • •

“0”—no tenderness “1”—mild tenderness “2”—moderate tenderness “3”—severe tenderness

As you begin to palpate remember to ask your patient to identify any tenderness by using the aforementioned scale. We will review the technique briefly for each muscle group and it is recommended to palpate using only one hand (dominant one) while using the other hand to support the head on the opposite side of the palpated one. Please note that the order listed above for the muscles to be palpated is only suggested to prevent or control contamination during the examination. This order allows all the extra oral muscles to be palpated first before moving inside the oral cavity for the medial and lateral pterygoid muscles. 1. Sternocleidomastoid∗∗∗: This muscle originates from the respective clavicle bone and inserts onto the mastoid process. Begin palpation as close to the original as possible and work your way up to the mastoid process. Please ask your patient to note if there is tenderness but where on the muscle. It is important to note that you may encounter patient’s feeling tenderness from the middle toward the mastoid process, and in some cases as you move toward the mastoid process the tenderness may become more intense. 2. Digastric Muscle∗: This muscle is divided into two sections that are separated by the hyoid bone. The posterior portion originates from the stylohyoid process and inserts into the hyoid bone while the anterior segment originates from the hyoid bone and inserts into the anterior portion of the mandible directly below the chin. Place your middle three fingers behind the ramus and begin palpating at a 45° angle and finish just above the “Adam’s apple.” Continue palpating until you arrive at the anterior portion just below the chin. See Fig. 4.27. 3. Superficial Masseter∗∗: This muscle originates just anterior to the ramus and inserts at the zygoma. The origination of this muscle is slightly posterior to the insertion and needs to be palpated in the same direction. To locate this muscle it may be helpful to ask your patient to clench. You should see the outline of the muscle as they

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a

b

Fig. 4.27  Palpation-depressor muscles, anterior digastric

4.

5.

6. 7.

8.

fully contract. In some cases you may not see the outline as described but will just need to place your fingers and feel for the muscle as they contract. This will confirm the outline to proceed further. Use your thumb and index finger and squeeze the muscle and move upwards toward the insertion. Be sure to feel and document any knots or trigger points that can cause muscle pain or tenderness. See Fig. 4.28. Deep Masseter: This muscle is much smaller and has a more vertical direction as compared to the superficial one. Measure two finger widths from the ear tragus where you should be able to feel a slight depression. At this point, use your index finger to palpate that spot and record any findings. This should not take long since this is a very small muscle. See Fig. 4.28. Temporalis∗∗: This is a fairly large spanning muscle that has three sections: anterior, middle, and posterior. All of these muscle fibers originate from the lateral side of the skull, and eventually insert on the coronoid process. As mentioned before, ask your patient to clench so you can identify it. Begin with two fingers, start palpating near the eyebrow and orbital rim, and then continue by moving upwards. This will cover the anterior segment. Continue palpating while moving posteriorly. Use the patient’s ear as a reference point to stop palpating. See Fig. 4.28. Posterior Neck: This area starts at the base of the skull and continues toward base of the shoulders. Palpate using thumbs and fingers and work your way down to the base. Trapezius: This muscle extends from the posterior base of the neck toward the lateral side near the deltoid (confirm the exact location). Palpate this muscle with the thumb on the back and place the rest of your fingers over toward the clavicle. Palpate this area using the fingers and thumb. Medial Pterygoid: This muscle can be located by first identifying the pterygomandibular raphe. This is the demarcation of the buccinator and posterior

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a

b

c

d

Fig. 4.28  Palpation-elevator muscles, masseter (A, B), deep masseter (C), and anterior + middle segment of temporalis (D)

a

b

c

d

Fig. 4.29  Palpation-positioner muscles, medial pterygoid (A, B), posterior temporalis (C), and lateral pterygoid (D)

pharyngeal muscle. Take you index finder and wrap it behind the pterygomandibular raphe. Push medially and you will feel this muscle. This must be done on both sides and note the patient’s response to this muscle. It is interesting to note that this muscle in most cases will always have some tenderness associated with an occlusal muscle disorder. See Fig. 4.29.

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9. Lateral Pterygoid: This muscle is very deeply positioned and cannot be palpated directly as the other muscles outlined above. There are two ways to at least find out if this muscle is tender. The first method is to have your patient close slightly or shift the mandible to the side that you are evaluating. Place your “pinky” finger behind the maxillary tuberosity and push. The pressure exerted here will transfer toward the lateral pterygoid muscle. [insert photo] The second method involves performing a resistance test against the muscle. While your patient protrudes the mandible (activating the lateral pterygoid muscle fully), place your thumb and index finger on the patient’s chin and push to resist for approximately 10  s. This will be enough time to produce any symptoms associated with the lateral pterygoid muscle. See Fig. 4.29.

4.6

Occlusion

The occlusion is the understanding of how the upper and lower teeth relate to each other. During the examination, it is important to not only classify this relationship (class I, II, or III or the relationship of the upper canines to the lower ones, along with the molar relationships), but also document functional occlusion characteristics, that is, how the upper and lower teeth relate to each other during functional movements. These can be listed as the following: (a) Dental midline (b) Overbite and overjet (c) Occlusal contacts (d) Right and left working interferences (e) Right and left balancing interferences (f) Protrusive interferences Placing articulating paper on both sides and having the patient occlude firmly will leave marks of the teeth showing the magnitude of contacts on all teeth in contact. Both working and balancing interferences can be observed by placing articulating paper over the teeth on the either side and asking your patient to lightly touch their teeth together. With clear instructions, have the patient move their mandible to the appropriate working side, then place the same articulating paper on the opposite side, and have the patient repeat the same working side. If there are any ­working/ balancing interferences, the articulating paper will leave marks on specific inclines. Repeat this for the opposite side to obtain information related to both right and left working and balancing interferences. The same process is used to document any protrusive interferences.

4.7

Oral Cancer Screening

This part of the examination consists of both visual and tactile in part. Palpate all soft tissues including the buccal mucosa, vestibule, lips, and under the tongue. During this part, pay attention if the patient provides any reaction to your palpation.

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The visual component simply pays attention to soft tissues that do not appear normal in nature.

4.8

Hard/Soft Tissue

At this point all of the soft tissues from the outside (face) to the inside (tonsils) must be examined with documentation. The hard tissue specifically refers to the dentition, and any condition associated with it. Remember that we are attempting to help our patient understand the signs of instability (wear, cracks, fractures, etc.). Prior to starting this part, it is recommended to inform the patient of what you are going to look for when examining their teeth. An example of this would sound like this: “ Mrs. Jones I am going to be examining your teeth and documenting any conditions that I see related to your teeth and fillings. If there is a defect on a tooth or filling, I will let Gina know to document this in your chart. In addition, I will be taking photos of each tooth so you can also see what I am seeing.” A statement like this allows the patient to be involved and to understand what is being done and documented. Remember to go tooth by tooth and document the following: 1. Missing teeth 2. Existing restorations (composite, amalgam, porcelain crowns) with conditions (open margins, etc.) 3. Cracks, fractures, wear, rotations 4. Decay 5. Recession Describing the conditions of the teeth in lay teams will allow your patient to have a better understanding of the overall health of their teeth. Using dental terminology causes the patient to be disconnected which may create feelings of uncertainty, and not understanding or knowing what is going on with their teeth. The risk of this may lead to a compromise in trust by the patient.

4.9

Intraoral Images

Upon the completion of the hard/soft tissue examination, the next step is to gather visual evidence by taking photos of each tooth using an intraoral camera. There is no preferential bias toward any particular brand of intraoral camera. However, I would emphasize that the quality of the image be paramount. Ideal images should be clear, crisp, and fog free. When taking images, be sure to take multiple photos of specific teeth from different angles to help illustrate the importance of the condition. Taking multiple photos will help you educate your patient on specific conditions related to proposed treatment. In addition, it is important to take photos of all healthy teeth. You would be surprised on what you will find on a healthy tooth using an intraoral camera. On many occasions, I have seen hairline cracks of teeth that normally could not be seen even with magnifying loops. This allows you to at least mention conditions like hairline cracks to patients and express the importance of the

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changes that are occurring. The idea of taking photos of healthy teeth becomes important as it provides a baseline documentation for your patient. Should a change occur in the future on a once healthy tooth, you can always reference the original photo to compare. If there was a condition associated with a tooth (crack, leaky margin, etc.) that became worse over time, then again this can be used as a reference when comparing the original image to the updated one. In general, it is recommended that intraoral photos should be taken if you see any of the following conditions: 1. Cracks 2. Wear 3. Recession and/or abfractions 4. Leaky margins on restorations 5. Decay 6. Calculus and/or signs of periodontal disease 7. Fractures (teeth and/or existing restorations) 8. Fistulas 9. Soft-tissue swelling 10. Soft-tissue lesions (tongue, buccal mucosa, floor of the mouth, etc.)

4.10 Periodontal Probing This part of the examination can sometimes be overlooked. However we cannot take this for granted for the foundation of the occlusion must be healthy, that is, the attached gingiva along with bone in the mandible and maxilla. What good is aesthetics and occlusion if the foundation is not healthy to support it? Thus, periodontal probing of the sulcus on each tooth is by far one of the most common parts of a comprehensive dental examination. Each tooth must be probed in six areas. Three (mesial, mid cervical, and distal) sulcus surfaces are on the facial and lingual sides. Healthy periodontal pockets should range between 1 and 3 mm in depth. In addition, bleeding sites must also be documented. Usually when the periodontal probe is removed from the sulcus, bleeding can occur suggesting inflammation (gingivitis) or depending on the depth of the periodontal probe (>5 mm) even periodontal disease. In order to get accurate readings, start with the most distal tooth, and place the periodontal probe parallel to the long axis of the tooth at the distal sulcus until the probe stops. Measure the reading as indicated on the mark, and move the probe through the sulcus toward the mesial. Stop mid buccal midbuccal to take the next reading and then continue along until the mesial recording is completed. This method will provide the most reliable and accurate measurements. The importance of accurate periodontal measurements must not be overlooked as this can have a profound effect on the final aesthetic results as well as any additional periodontal treatment (crown lengthening and/or gingival grafting) that may be required to achieve the optimal result. In addition to the aforementioned technique, it is also important to document gingival recession as well as tooth mobility. Recession is simply attachment loss which also implies bone loss. Teeth that exhibit gingival

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recession in the aesthetic zone may be good candidates for grafting procedures as long as there are adequate papillae present.

4.11 Appropriate Radiographs Once you have determined the functional and structural diagnosis, ordering the appropriate radiographs is the final step in completing the examination. Usually, a full mouth series is taken at this time. This consists of a standardized 18 radiographs [7]. However, depending on your findings of the TMJ, it may be necessary to order either CT or an MRI for further evaluation. Figure  4.30 illustrates an MRI of a patient which clearly shows the articulating disc in the anterior position during the closed position. The disc should be articulating on the condylar head in the closed position. In the opening phase, the disc recaptures onto the condylar head (outlined in yellow). Today, using CBCT is becoming very popular as a means to substitute traditional radiographs. Regardless of what you choose for your patient, it is important to remember that the examination should be completed first before any appropriate radiographs are ordered. This comes back to what was stated earlier in that to become a physician of the masticatory system one must begin to think like a physician. A physician would not order any diagnostic tests or X-rays until an examination (simple or complex) is completed on their respective patient. At this point steps (1)–(10) have been discussed in detail. These steps will give you a better understanding of the dental health of your patient, both structurally and functionally. This gives clarity as to whether the same patient is stable or unstable. A masticatory system is stable when teeth, muscles, and TMJ are healthy together. In

Fig. 4.30  MRI image illustrating the right temporomandibular joint in the closed and open positions. The articulating disc recaptures onto the condyle head in the open position

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Fig. 4.31 Stable masticatory system—TMJ, muscles of mastication, and teeth are all stable

Fig. 4.32 Unstable masticatory system—any combination of TMJ, muscles of mastication, and teeth is unstable

other words, teeth do not exhibit signs of instability, muscles are not sore or show no signs of tenderness, and the TMJ can be loaded firmly with no tension or tenderness. Figure 4.31 illustrates this perfectly in the triad of the masticatory system. On the contrary, a masticatory system is unstable when any one of the three components shows signs or symptoms. See Fig. 4.32 as this triad illustrates any combination of the three parts of the masticatory system that may be unstable. If the examination is not completed correctly, then determining whether your patient’s masticatory system is stable or unstable becomes more challenging. When the examination is completed correctly, you will find a vast majority of your existing patients to be unstable. Having said this, the last two remaining steps in the complete examination relate to the “occlusal analysis.” This analysis begins with taking appropriate diagnostic records including digital photography. We will continue our discussion on these last two steps in the next chapter.

References

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References 1. Dawson PE (2007) Functional Occlusion: From TMJ to smile design. Mosby Elsevier. St. Louis, MO. 2. Khanna N (2011) The art of the complete dental examination—part 1. J Ontario Dent Assoc (Ontario Dentist) 95(7):36–39 3. Khanna N (2011) The art of the complete dental examination—part II. J Ontario Dent Assoc (Ontario Dentist) 95(8):22–26 4. Griffiths RH (1983) Report of the president’s conference on the examination, diagnosis, and management of temporomandibular disorders. J Am Dent Assoc 106(1):75–77. https://doi. org/10.14219/jada.archive.1983.0020 5. Rieder CE (1978) Maximum mandibular opening in patients with and without a history of TMJ dysfunction. J Prosthet Dent 39(4):441–446. 6. Dawson CE (1995) New definition for relating occlusion to varying conditions of the temporomandibular joint. J Prosthet Dent 74(6):619–627. 7. Kantor ML (1988) Radiographic examination of comprehensive care patients in U.S. and Canadian dental schools. Oral Surg Oral Med Oral Pathol 65(6):778–781. https://doi. org/10.1016/0030-4220(88)90029-1

5

Diagnostic Records: What to Take and Why

“Tide and Time wait for no man.” Geoffrey Chaucer, Poet

Contents 5.1  Discussion 5.2  Facebow 5.3  Centric Bite Record 5.4  Perfect Impressions 5.5  Digital Photography References

 89  96  100  111  111  123

5.1  Discussion As we discussed in the previous chapter, the complete examination is the most important step to a proper diagnosis for your patient. There are many protocols available, but there are no shortcuts in gathering all the data needed to provide your patients with an accurate and predictable treatment plan [1]. A complete examination consists of 12 steps. The first ten steps are dedicated to understanding the functional (occlusion, temporomandibular joints, centric relation, range of motion) and structural (structural and periodontal integrity, dental caries) conditions of your patient’s masticatory system. This information becomes useful in determining if the patient’s masticatory system is either stable or unstable. A masticatory system is stable when temporomandibular joints, masticatory muscles, and teeth are all healthy and do not exhibit any signs of breakdown (see Figs. 5.1 and 5.2). On the other hand, a masticatory system is considered unstable when any combination of the three components exhibits signs of breakdown (see Figs. 5.2 and 5.3). Once you have made the determination that your patient’s masticatory system is “unstable,” it © Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_5

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Fig. 5.1 Stable masticatory system. TMJ, muscles of mastication, and teeth are all stable

Fig. 5.2  Patient example of stable masticatory system

Fig. 5.3 Unstable masticatory system. Any combination of instability of either TMJ, muscles of mastication, or teeth

is time to complete the final two steps of the comprehensive examination. The remaining two steps are considered necessary in order to solve structural and functional problems. The process of solving these problems will be discussed later in

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Fig. 5.4  Patient example of unstable masticatory system

Chap. 8, and is referred to as diagnostic occlusal treatment assessment (DOTA). The last two steps, 11 and 12, in the comprehensive examination consist of obtaining diagnostic records and digital photographs. This chapter focuses on the relevance of the diagnostic records and digital photography. It is paramount that these diagnostic records be correctly completed with precision and accuracy. Any inaccuracies in the transfer of the information will compromise the predictability of the outcome. Less predictability results in a different outcome for our patients, and often results in a more stressful process for both dentist and patient (Fig. 5.4). There are four components in obtaining accurate diagnostic records: 1. facebow transfer, 2. centric bite record, 3. perfect impressions, and 4. digital photography. These four components serve each other and must be completed with accuracy and precision. Inaccuracies in any of the four components will lead to diagnostic records that will not reproduce the same occlusal relationship established for your patient. The purpose and goal of obtaining accurate diagnostic records are the following: 1. View the patient’s occlusion in three dimensions: Clinically, when we observe our patient’s dentition, it is from the vantage point with limitations of the soft tissues. Having an accurate set of the patient diagnostic casts that are mounted on a semi adjustable articulator will provide the dentist with multiple views of the respective occlusion. The advantage to the dentist is to properly study and evaluate the occlusion from any angle. See Fig. 5.5. 2. Appreciate the discrepancy between centric relation and maximum intercuspation: One of the requirements to create a stable occlusion is to have equal contacts on all teeth in centric relation. An unstable patient will most likely have a discrepancy between centric relation and maximum intercuspation. As part of the examination, you can seat the condyles in centric relation and once confirmed, ask your patient to close until the first tooth touches. This identifies the first deflective contact in centric relation. Once documented, the patient is asked to squeeze their teeth allowing the mandible to displace allowing all the teeth to finally occlude.

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Fig. 5.5  Mounted models in centric relation seen from right, left, anterior, and posterior sides

Fig. 5.6  Illustrating the difference between centric relation and maximum intercuspation

This modified slide from centric relation into full occlusion is called maximum intercuspation. This can be duplicated on the mounted models. The important point is to make sure that what was documented in the patient’s records is duplicated onto the mounted models. Figure 5.6 illustrates the differences in occlusion

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Fig. 5.7  First point of contact in centric relation

from centric relation and maximum intercuspation. Here you can see a significant difference between the two positions. In addition, please note the amount of space present in the anterior area. Figure 5.7 illustrates the first point of contact in centric relation. Here the left second molars (#2.7 and #3.7 or tooth #15 and #18) are the first teeth to contact in centric relation. 3. Document interocclusal relationships of the teeth, eccentric movements (working, non-working, and protrusive): When analyzing the occlusion, it is important to understand how the present occlusion works in eccentric movements. Any posterior interferences during working and non-working movements can produce posterior teeth with abfractions, worn cusps, and mobility over time. The best way to document any interferences is to simply use articulating paper ribbon during the complete examination and document any interferences in the chart. Confirm this with articulating sheets on the mounted models by moving the upper chamber of the articulator in any excursive direction. Ideally, we would like to only see lines of articulating ribbon on the lingual surfaces of the maxillary canine teeth, and no posterior teeth interferences on either working or non-working movements. Figure 5.8 illustrates all the working and non-working interferences. It is interesting to note in this case that during left working, the lower and upper lateral incisors are in heavy contact. Eliminating this contact will create a smoother left working movement both on the articulator and in the patient’s mouth. 4 . Study, analyze, and if needed modify the shape, size, and contour of anterior teeth: When designing mandibular and maxillary anterior teeth, it is best done on the mounted models using references from our digital photography. Creating an ideal incisal plane(s) of occlusion may involve reshaping to create ideal contours, and adding wax to idealize the incisal edges. Remember, these design changes are your best guess, and must be tested on the articulator to confirm the new shape and contours do not create more interferences during the excursive movements. Figure 5.9 illustrates the same patient case where the mandibular anterior teeth were reshaped along with waxing in the ideal incisal edge.

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Fig. 5.8  Excursive interferences in both working and non-working sides of mounted models

Fig. 5.9  Modifying the anterior teeth to ideal shape and contour using reshaping and waxing

5. Create a stable occlusion: Equilibration is an essential, conservative method of achieving a balanced occlusion. In most cases it begins with eliminating the first point of contact in centric relation. As this first contact is now eliminated, further premature contacts arise needed further adjustments. This process continues to move contacts to an ideal place (cusp to fossa) by altering inclines that are in the way. In some other situations, it may be necessary to add to a tooth (wax in the contact) to create the ideal occlusal stop. Figures 5.10 and 5.11 illustrate the start and completion of equilibration. In this case, only reductive equilibration was needed. The purpose here is to determine whether equilibration (whether reductive and/or additive) is a means of establishing an ideal occlusion.

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Fig. 5.10  Equilibration begins by reshaping the first point of contact in centric relation

Fig. 5.11  Completed equilibration illustrating contacts on all teeth in centric relation. Note: there are no posterior interferences during excursive movements

6. Predictable treatment planning: Once the ideal occlusal scheme has been established on the mounted models, the next step is to transfer this information to the patient’s mouth in the form of treatment. Fabricating stents from the waxed-up model allows the dentist to transfer information related to incisal edge position and facial/lingual contours. The other important point here is that based on the wax-up (shape, contours, etc.) this will determine the design of your tooth preparation. Figure  5.12 illustrates the transfer of both mandibular and maxillary stents to the mouth. Here the maxillary incisal edges need to be lengthened with composite, and the stent clearly shows how much composite will be needed. The same can also be said for the mandibular arch. Of the four components of the diagnostic records described, the first three are used together allowing the dentist to transfer the occlusal and functional relationship of the patient to the articulator. There is great debate over the choice of using a fully

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Fig. 5.12  Silicone matrices fabricated from wax-up and used as a guide and reference intraorally

adjustable versus a semi adjustable articulator. To be perfectly honest, the real debate should be why aren’t dentists routinely using an articulator period? The answer to this question will detract from the purpose of this book. What I do know is that if you provide a more simplified articulator, it will create less confusion and possibly encourage dentists to use. It is the authors’ opinion that a comprehensive restorative dentist cannot solve occlusal problems predictably without the use of an articulator. The author uses a semi adjustable articulator. In this case, the only components that can be adjusted are the condylar path and the incisal guide pin (see Fig. 5.13a, b). We will discuss the importance of each component and its significance to the occlusal analysis.

5.2  Facebow The mandible is the only moveable part while the maxilla is the fixed part of the masticatory system. However, on the vast majority of articulators, the opposite relationship exists between the maxilla and mandibular chambers. The upper articulator chamber is movable while the lower is fixed. Duplicating the exact occlusal relationship on an articulator first requires the use of a facebow transfer. The purpose of the facebow is to reestablish the relationship of the maxilla to the condyle (see Fig. 5.14) in both horizontal and vertical positions. Figure 5.15 illustrates the importance of recognizing the horizontal plane of occlusion. In this case, the ear bow has a “level” to make sure that the horizontal plane of the patient’s head is parallel to the floor. Here we see the patient’s eye area parallel to the floor, but the maxillary occlusal plane is not. If the casts were not mounted on the semi adjustable articulator, then the laboratory technician will make reference to the bench top to establish the horizontal plane of occlusion. The best way to correct a horizontal cant is to send the technician both mounted models and digital photography. At this point, the maxillary cast can be mounted to the upper chamber. Figure 5.16 illustrates the relationship of the maxillary cast on the articulator. Here the ear bow and bite fork match the plane of occlusion to the mandibular condyle. The author uses a semi adjustable articulator that can accept a facebow. The system used is the Denar® slidematic facebow system. The system includes all the components

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a

b

Fig. 5.13 (a) Semi adjustable articulator: frontal and side views. (b) Illustration of adjustable condylar path. (DENAR COMBI II—Whip Mix Corporation)

Fig. 5.14  Relationship of the maxillary arch to the TMJ, and how the facebow transfers this to the articulator

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Fig. 5.15  Horizontal component of the occlusal plane verified with facebow transfer

Fig. 5.16  Maxillary cast mounted to the articulator using facebow transfer illustrating the connection of the maxillary plane to the TMJ

needed to complete the facebow transfer. Figure 5.17 illustrates the armamentarium in the kit. It includes a ruler which has a “reference plane locator.” It is designed to make reference to an arbitrary distance from the lateral incisor to the face. Figure 5.18 illustrates the reference plane locator on the patient and how this distance relates to the maxillary cast mounted on the articulator. This distance will center the maxillary cast between the upper and lower chambers of the articulator. The first step is to take the reference plane locator, place the flat edge at the maxillary right lateral incisor, and mark the face where the ruler ends. Subsequently,

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Fig. 5.17  Armamentarium used for recording the facebow

Fig. 5.18  Reference plane locator used on patient and illustrated on the mounted maxillary model

align the bite fork to the patient’s facial and not the dental midline. The relevance here is that if your patient has a true dental midline shift, then it needs to be duplicated on the articulator. Since a great majority of patients have the same dental and facial midlines, this usually does pose an issue. Using any bite registration material, place an adequate amount on the bite fork, and place against the maxillary occlusal

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Fig. 5.19  Recording facebow, steps 1–4

arch. During this process, have the patient bite down on cotton rolls for stability. Figure 5.19 illustrates the first four steps in recording the facebow. Once the material has been completely set up, continue by placing the ear bow assembly onto the bite fork while sliding the earpieces appropriately to a medial anterior position inside the ear. Adjust the ear bow vertically so the reference pointer lines up to the mark left by the reference plane locator, and tighten the screw. Continue to adjust the “level” on top of the ear bow horizontally so that the “bubble” is centered, and tighten the screw. Figure 5.20 illustrates these last two steps, and Fig. 5.21 illustrates the completion of the facebow record.

5.3  Centric Bite Record As mentioned earlier, the facebow provides a reference to transfer the maxillary cast to the upper chamber of the articulator. As the term describes, a bite record is taken in centric relation. Bimanual manipulation is the most reliable technique used to place the mandibular condyles into centric relation. As a result, this same technique is used in taking the centric bite record. The centric bite records the relationship of the mandibular teeth as it closes. Because we are using bimanual manipulation to seat the joints, the mandible can close on an arc. This concept is also termed “arc of closure.” The mandible freely closes on an arc from full translation while the center of rotation is at the condyle. As a result,

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Fig. 5.20  Recording facebow, steps 5 and 6 Fig. 5.21 Recording facebow completed

the anterior teeth are furthest away from this center of rotation, while the posterior teeth are closer. As the mandible closes on this arc, the distance that separates the posterior from the anterior teeth is shorter. Record centric bite that occurs on the same arc of closure. Figure  5.22 illustrates this concept through BiteFx®. There are many materials available to record a centric bite: bite registration material, wax rims, baseplate wax, and Denar® bite registration wax. Figure 5.23 illustrates all four materials. Bite registration material is prone to break when trimmed, and the material itself picks up too much detail of occlusal surfaces. This creates some inaccuracies as the bite registration will not adapt as well to the stone model. Wax rims and baseplate wax can distort due to temperature changes which in itself will not provide an accurate mounting. We judge impression materials based on accuracy, ability to work in moist environments, and stability. Denar® bite registration was judged as the most accurate and stable material to use when recording at centric bite [2]. In addition, this material is designed to be compatible with the arc of closure. Figure 5.24 illustrates the dimensional shape of the Denar® wax. From the

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lateral side, the width of the Denar® wax in the posterior area is narrower as compared to that in the anterior segment. As the mandible closes on its arc, less posterior interocclusal space is needed to record the bite while more is needed toward the anterior interocclusal space. This design allows the patient to close into the wax with minimal contact. The anterior cutout space is designed to make room for an anterior deprogrammer. The use of an anterior deprogammer is to relax any tension in the lateral pterygoid muscle(s) providing enough room to place the Denar wax between maxillary and mandibular posterior teeth [3, 4]. This bite technique does not record the first point of contact in centric relation, but records a reference to the arc of closure of the patient. When the mandibular cast is mounted to the maxillary cast (via the centric bite records), the wax is then removed, Fig. 5.22  The arc of closure-interocclusal space increases from posterior to anterior along the arch or rotation of closure

Fig. 5.23  Materials used to record centric relation: Denar wax, baseplate wax, wax rim, and bite registration PVS. (McKee J.R.: J. Prosth. Dent. 1997, Mar:73(3), 280–284)

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Fig. 5.24  Denar wax seen from anterior and lateral views. Completed Denar wax trimmed. (Denar® Bite Registration Wax, Courtesy of Whip Mix Corporation)

the models are allowed to close on the established arc, and eventually the first point of contact will be duplicated. When done with the proper technique, the mounting of both maxillary and mandibular models on the articulator must duplicate the same first point of contact as documented in the patient’s mouth. Figures 5.25 and 5.26 illustrate the steps needed in completing an accurate centric bite record. The Denar® deprogrammer has a flat end which is used to rest against the anterior teeth of the mandibular dentition. The author has created two notches on the flat surface of the deprogrammer (step 1). This will be used to create retention of the centric relation index. The process begins with heating compound and adding it to well of the deprogrammer (steps 2 and 3). Once the deprogrammer is seated against the maxillary anterior teeth, a flat plane is used to confirm that the deprogrammer is parallel to the plane of occlusion. The establishment of this plane will allow the patient to deprogram the muscles without putting excess stress on the temporomandibular joints (steps 3 and 4). Using bimanual manipulation, the lower anterior teeth are brought into contact with the flat plane of the deprogrammer. While the patient holds this position, flowable composite (or block-out resin) is injected into one of the notches and enough is placed to engage with one or two mandibular central incisors. The material is light cured and the index is verified with bimanual manipulation (steps 6 and 7). At this point, the condyles are seated in centric relation, and all that is needed now is the wax bite. The Denar® bite registration is trimmed with a heated knife so that it fits comfortably (step 8). Both sides are heated until the wax turns to a darker blue color and then seated against the maxillary teeth, and then using bimanual manipulation, close the mandible into the index (step 9). This should leave an imprint of only the buccal and lingual cusps on either side. The wax is now trimmed appropriately by cutting through the deepest part of the buccal cusps of the maxillary side and beveling toward the mandibular buccal cusps (steps 10 and 11). The wax is tried in to make sure that there are no more cusps that are in the way. The wax is chilled in ice water for 1 min, inserted again, and verified (see Fig. 5.27). Then it is placed in a plastic zip-lock bag with water and stored inside a refrigerator. When it is time to mount your diagnostic casts, remove the wax from the refrigerator. Diagnostic models that are mounted correctly will reproduce

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Fig. 5.25  Centric bite record: establishing anterior deprogrammer with the correct plane

Fig. 5.26  Centric bite record: creating incisal index on deprogrammer, recording bite with Denar wax, and trimmed to completion

the arc of closure on the articulator which will also reproduce the first point of contact in centric relation. Figure 5.28 illustrates completed mounting. Here accurate duplication is achieved of the maxillary relationship to the condyles, as well as the arc of closure (see Fig. 5.29). On the other hand, not using an articulator changes the accuracy of inter occlusal models because the joint position has not been taken into consideration. For example, we commonly see hand-articulated models using a plastic hinge as the reference point of the temporomandibular joint. Figure 5.30 illustrates an example of hand-articulated models. Here the point of rotation occurs at or near the occlusal plane. Although there exists

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an arc of closure, it does not resemble what occurs in nature. In addition, excursive movements cannot be measured nor duplicated accurately as compared to an articulator. Restorations completed on this framework invariably are never accurate and require multiple adjustments to make the occlusion work. There is no comparison of this model to what we know in Fig. 5.29. Sometimes there are discrepancies between what was documented in the patient’s record and what is seen with the results of the diagnostic records; then one must explore several factors that could be responsible for the inaccuracies: for example, if you noted that your patient has a premature contact on the upper left second molar, but when you completed the records on the same patient, you noticed that mounted

Fig. 5.27  Intraoral views of completed centric bite record, anterior, right, and left views

Fig. 5.28  Facebow mounting of upper cast, Denar wax for mounting of lower cast, completed mounting in centric relation

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models do not demonstrate the same first contact. Let us look at the reasons why this occurs and explain the reasoning for the inaccuracies in the diagnostic records. 1. Impression Material/Technique: Alginate impressions are not as accurate because the properties of the material are dependent on the operator. The amount and the

Fig. 5.29  Mounted models duplicating the same arc of closure

Fig. 5.30  Hand-articulated mounting illustrating a different arc of closure as the hinge position is in the same plane as the occlusal plane

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temperature of the water used to mix alginate can case variations in the setting time and the strength of the material. Alginate impressions begin to distort very quickly and as a result are required to be poured fairly quickly. In addition, alginate materials are not recommended for multiple pours of the same impression. Other disadvantages of using alginate include the increased potential for voids, especially on the occlusal surfaces. For this reason, the author recommends using a PVS impression material (as mentioned above) for all impressions. The technique mentioned above must also be done with accuracy. Some pitfalls to watch out for include voids or pockets between the light-body and initial PVS putty material. Before taking the light-body wash, make sure that you either air-­ dry or wipe the occlusal surfaces to avoid the potential for saliva to get trapped between the light- and heavy-body material. See Figs. 5.31 and 5.32. 2. Inaccurate Facebow Record: The purpose of the facebow record is to accurately duplicate the maxillary occlusal plane to the temporomandibular joint. The technique in taking this record can involve help from the patient and if the patient inadvertently moves or causes the facebow fork to move or be displaced before the material is set up it will create distortion. This can occur in both horizontal and vertical planes, and results in an inaccurate maxillary occlusal plane reference. 3 . Centric Bite Record: This is by far the most common reason experienced by clinicians early on when mounting the diagnostic models. The choice of material used to take the centric bite record will play a significant role in the outcome of the mounting. There are situations that can cause even this accurate material to create an inaccurate mounting. During the technique of taking the centric bite record, it is recommended to chill the Denar® wax in ice-cold water to allow the wax to cool quickly and maintain its accuracy. Storing the wax at room temperature after cooling will cause some changes in the wax. This can cause the wax to warp. When articulating the warped Denar® wax to the stone model, you may see a “rocking” effect (mesial/distal or left/right) of the wax. To make this part more successful, the author recommends that the wax be stored in a refrigerator until used to mount the models. In addition, overheating the Denar® wax prior to taking the centric bite

Fig. 5.31  PVS impression technique

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Fig. 5.32  Ideal PVS impressions completed

record can result in a bite registration that has too much anatomy. Having too much anatomy in the wax creates a situation where the wax may not align correctly onto the models as compared to the mouth. For example, Figure 5.33 illustrates Denar wax that was overheated showing detailed anatomy, especially in the maxillary arch. Another explanation for an inaccurate centric bite record is the incorrect trimming of the Denar® wax. It is recommended that the upper arch be trimmed through the buccal cusp area, and the distal half of the second molar be removed. The lower arch must be beveled toward the buccal cusp area. Figures 5.33 and 5.34 both illustrate Denar wax that was not properly trimmed. Here we can see the following: (a) Distortion in the models (b) Buccal cusps that are covered with wax (c) Wax extending too far posteriorly on the left side (d) Wax not trimmed through the maxillary buccal cusp height On the contrary, Fig. 5.35a–d illustrates the ideal Denar wax bite on the same patient, and we clearly see the following difference: (a) Wax trimmed through the maxillary buccal cusps (b) Properly beveled from the maxillary buccal cusp tip toward the mandibular buccal cusp tip (c) Minimal anatomy in the wax (cusp tips only on both maxilla and mandibular teeth) (d) Wax trimmed posteriorly to the mesial buccal portion of maxillary second molar 4 . Bimanual Manipulation Technique: This technique has a direct relationship to the accuracy of the centric bite. If the bimanual manipulation is not correctly

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Fig. 5.33  Improperly trimmed Denar wax

Fig. 5.34  Improperly trimmed Denar wax on study casts

done, then centric relation cannot be verified in the patient and the corresponding mounted models. 5. Bounce Back of Intruded or Mobile Teeth: There are patients with teeth that are intruded due to malocclusion or ones that have some mobility due to excessive occlusal forces. When taking impressions, the mobile tooth (or teeth) may change position while the impression material is setting. However, when the centric bite is taken, the pressure exerted on the wax wafer when the mandible closes in centric relation on either intruded or mobile will create a bite record that is different from that of the mouth. Unfortunately, this error will not be noticed until after the models are mounted and cross-referenced to the documentation in the patient’s record. 6 . Powder/Liquid Mixing Ratio: When pouring diagnostic impressions, not only is the type of stone important, but also staying accurate to the amount of water used to mix the stone is just as important. Too many dental personnel (including dentists) do not take this seriously enough. This will lead to various setting properties that will produce a model that is always inaccurate. A dental stone that has

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less than 0.1% shrinkage setting is the most ideal one to use. You may contact your dental supplier for more information on the various brands. The author recommends using a separate mounting stone to mount diagnostic models. The characteristics of mounting stone include low expansion (0.08% or less), fast setting and is very hard. This will provide even more accuracy when mounting models. a

b

c

Fig. 5.35 (a) Ideal trimmed Denar wax intra oral view. (b) Ideal trimmed Denar wax on study casts. (c) Properly trimmed Denar wax. (d) Comparison of bevel angle in both properly and improperly trimmed Denar wax

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d

Fig. 5.35 (continued)

5.4  Perfect Impressions Accurate impressions are paramount to properly analyze occlusion and treatment plan. Many clinicians do use alginate-type products, but this type of material is not as accurate and usually cannot be poured multiple times. In the everyday practice, it is best to use polyvinyl siloxane (PVS) impression material [5]. This type of material is much more accurate, and multiple models can be made from the same impression. The criteria for accurate impressions should be similar to those taken during fixed prosthodontic preparations. They are as follows: occlusal anatomy captured with no voids, and gingival margins intact along with all vestibule anatomy present. The author recommends that a heavy-body putty be used as the initial material. This is seated in the patient’s mouth, after approximately 1 min remove the heavy-body impression, and using a light-body impression material create a “wash” impression. Figure 5.32 illustrates an example of the technique for taking impressions, while Fig. 5.36 illustrates an example of ideal diagnostic impressions. Today there are other means with technology that will scan teeth and print models with more accuracy than the traditional methods outlined in this chapter.

5.5  Digital Photography Digital photography has many uses in dentistry. Shade selection, before and after photos, and general documentation are just a few examples of why dentists choose to use digital photography. I have asked many dentists through the years if there are other reasons to use digital photography. Some use digital photography to treat aesthetic, full-mouth restorative cases while others just simply use it because they want specific information when it comes to shade matching. What this means is that these

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dentists have already treatment planned before deciding to use digital photography. The author would like to suggest changing this mindset and making digital photography the standard of care when gathering appropriate diagnostic records. In other words, we can use digital photography along with our other diagnostic records to formulate a treatment plan that is predictable, properly planned, and can be easily executed. This part of the diagnostic records begins with the basic understanding of the requirements needed to produce not only the correct images but also at the right settings. We will separate our discussion into three categories to help explain the important use of digital photography: armamentarium, camera settings, and techniques for taking appropriate photos. The point in this discussion is to take the appropriate diagnostic photos correctly and be able to use the information provided in the photos to predictably plan for the ideal treatment. 1. Armamentarium: Taking great dental photographs requires the right equipment, training, and experience. The equipment consists of a digital camera with a macro lens, tissue retractors, occlusal mirror, and black contrast. The author does not endorse any particular brand, but the most common camera brands used for dental digital photography are either Canon or Nikon. The macro lens used for digital photography can be either 60 or 100 mm (preferred). The smaller the lens, the closer you will have to be on our subject to take the image. Most dental digital cameras purchased through a vendor will come equipped with the manufactured 100 mm macro lens. The photos would not exist with proper flash. There are two types of flash used for dental photography: a ring flash, and dual-point flash. The ring flash is the most widely used due to its simplicity of operation and quality of photos. This is most advantageous for someone just starting with digital photography. The flash is mounted at the end of the lens, while the power source on the camera. Photos taken with a ring flash will have light centered in the front of the image, dispersing the light outwardly. The dual-ring flash is placed on each side of the camera which is held by a special bracket. Unlike the ring flash, the light (flash) can be adjusted by changing the distance on the bracket. This is ideal to use when taking photos to capture more detail. Figure 5.36 illustrates the differences between the two types of camera flashes. Tissue retractors are necessary to move the lips away from the teeth allowing the photographer to capture intraoral photos. Tissue retractors are made of plastic or metal and of various sizes. Occlusal mirrors used in dental photography capture occlusal arches, and need to be used in conjunction with tissue retractors. Finally, black contrasters are designed to provide a backdrop when taking close-up photographs of anterior teeth. The contrasters are made of black anodized aluminum and are designed to absorb light behind the anterior teeth. These photos become important when texture, color, and translucency are needed for communication with laboratory technicians. 2. Camera settings: The settings for taking dental photographs can vary depending on whether you are taking portrait or intraoral photos. We will keep this discussion simple to explain the basics of camera and lens settings. There are three areas of importance to photography, shutter speed, aperture, and magnification ratios. Shutter speed is simply the time it takes to capture a picture, in

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Fig. 5.36  Digital camera: ring and dual-point flashes Fig. 5.37  Digital camera settings: AV mode and f stop

other words the time light takes to hit the digital sensor. The higher the shutter speed, the faster the shutter opens to allows light in. For dental photography, the ideal setting is at “AV mode” or aperture priority mode. At this setting, the camera will automatically set the shutter speed based on the aperture setting selected. Aperture settings are usually located on the right side of the camera settings. Aperture is the amount of light entering the camera, and is represented as “f stop.” Figure  5.37 illustrates both settings where the f stop is controlled by the dial outlined in blue. The aperture settings range from f 5.6 to f 32. The lower the setting, the more light enters the camera which provides a smaller depth of field. These settings are ideal for portrait photos. Figure 5.38 illustrates a diagram outlining the amount of light entering the camera, and

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Fig. 5.38  Digital photography: small aperture results in a smaller depth of field Fig. 5.39 Digital photography: photograph taken with aperture setting off 5.6

Fig. 5.39 provides an example of a photograph taken at a low aperture setting of f 5.6. Note how the depth of field is small and there is little focus on any part of the flowers. On the other hand, a higher aperture setting will allow less light to enter the camera, and provide a larger depth of field. These settings are more ideal for intraoral photos. Figure 5.40 illustrates a diagram of how much less light enters the camera, and Fig. 5.41 shows the same photo taken at a higher f stop of 22. It is clear that there is more detail seen in all of the flowers.

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Fig. 5.40  Digital photography: large aperture results in a greater depth of field Fig. 5.41 Digital photography: photograph taken with aperture setting of f 22

This would be the ideal f stop setting to take intraoral photos of teeth and soft tissue. Figure 5.42 illustrates both photographs side by side at the respective f stop settings. The lens of the camera is responsible for letting in light to a sensor inside the camera body, thus creating a digital image of an object. All of the settings mentioned above affect how the image is portrayed through the lens. There are two settings on the lens: “focus” and “magnification ratio.” Figure 5.43 illustrates the 100 mm macro lens with both settings outlined in red. Focus is either manual or automatic, and it is recommended to use

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Fig. 5.42  Digital photography: side-by-side comparison of both f 22 and f 5.6 apertures Fig. 5.43 Digital photography: macro lens settings

autofocus for portrait photographs as the camera will autofocus on the subject regardless of the distance at which the photo is taken. On the other hand, manual focus is recommended for dental photographs. This assures that the photos taken are at the same distance every time. The magnification ratio will determine the distance at which the photo is taken (as long as we are in manual focus setting), and what is seen in the lens. This ratio ranges from 1:1 to 1:5. If the ratio increases, you will pick up less of the object in the field of view, and in order to focus on the object, you will have to move further away. The opposite occurs when the ratio is smaller; you will have more of the object in the field of view, and will have to move in closer to focus. It is

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recommended that intraoral photos be taken at either 1:1.5 or 1:3 magnification ratios. The reasons for the different ratios will be discussed in the next section. 3. Techniques in dental photography: Dental photography is currently being used for shade selection, lab communication, and documentation final outcomes of treatment to just name a few. However, photography can also be used to analyze occlusion, incisal edge position, and soft tissue profile. The treatment planning process is not completed without the appropriate photos. As mentioned before, most dentists treatment plan first before deciding on whether the patient case should need to be mounted on an articulator. The same can be said about photography—treatment plan first, and depending on the type of treatment, decide whether photographs are needed. This mindset is difficult to change but in order to plan treatment comprehensively, taking digital photos as part of the treatment planning process is mandatory. The digital photographic series consists of 24 photos. Of these, three are full-face photographs, while the rest are intraoral. Figure 5.44 outlines all 24 photos. Here, you will note that some of the photos have been outlined with different colors. The photos outlined with “yellow” were taken with an f stop of 22, magnification ratio of 1:3, and manual focus setting. The photos outlined in “purple” were taken with an f stop of 22, magnification ratio of 1:1.2, and manual focus. Lastly, the photos outlined in “blue” were taken with an f stop of 5.3, and autofocus (magnification ratio was not needed since we were in autofocus mode). As mentioned earlier, digital photography can be used to analyze the patients’ occlusion (curve of Spee, curve of Wilson, lower incisal plane, etc.), and incisal edge position. One of the most important elements

Fig. 5.44  Digital photography complete series of 24 photos

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Fig. 5.45  Digital photography: photos taken to determine incisal edge position

of function and aesthetics is the incisal edge position. Using digital photography, the clinician can determine whether the patient has an existing deficiency with the incisal edge. Among all 24 photographs, only 4 are used to evaluate the vertical and horizontal incisal edge position. Figure 5.45 illustrates which four photos are used to evaluate both horizontal and vertical positions of the incisal edge. The photos used for the vertical determinant are the “repose” and “E smile” photo, while the “tip-down” and “lateral smile” photos are used for the horizontal determinant. In order to take these photographs correctly, both the patient and photographer need to be in an ideally seated position. Figure 5.46 illustrates the position of both the patient and photographer. Please note that both patient and photographer are seated at the same level, and the camera lens is pointing perpendicular to the facial surfaces of the anterior teeth. Figure  5.47 illustrates the “smile” photo taken with the same settings as described earlier. Here the central incisors are centered in the photo, contracted lips and commissures are in the frame, and there is full display of both teeth and soft tissue. With the patient and photographer in the same position, the patient is now asked to say “EEE!” This is referred to as the “E smile” or social smile photo. Here we see more display of both teeth and soft tissues. Figures  5.48 and 5.49 illustrate the patient position and the resultant photo. Here we are evaluating the incisal edge position in relation to both the upper and lower lips. An acceptable incisal edge position in this photograph would be somewhere between 50% and 70% of the distance between the inferior border of the upper lip and the superior border of the lower lip. It is not required to measure this distance quantitatively, but to only use the photograph and visually make that determination. To confirm the incisal edge, a second photograph is taken. The “repose” or “rest” position is taken by asking the patient to lick their lips and say “MMMM.” Teeth and lips are apart in the relaxed position. Figures 5.50 and 5.51 illustrate the patient position and the

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Fig. 5.46  Digital photography: photographer and patient position—“smile”

Fig. 5.47 Digital photography: “smile” photograph

resultant photograph. Here we are evaluating how much incisal edge is ­displayed at rest. For a youthful person, we would expect to see anywhere between 1 and 3 mm of incisal edge display. As patients get older, we tend to see less display due to gravity and decreased collagen in the skin. When taking this photograph on an older patient and if you do not see adequate display of the incisal edge, refer to the “E smile” photo for confirmation. For example, if there is not enough display at “rest,” but the “E smile” photo provides enough incisal edge, then do not change the incisal edge position. The horizontal component of the incisal

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Fig. 5.48  Digital photography: photographer and patient position—“E smile” Fig. 5.49 Digital photography: “E smile” photo used to determine the vertical incisal edge position of the maxillary central incisor

edge position is determined by the “tip-down” and “lateral smile” photographs. Figure 5.52 illustrates the patient tipping the head about 45° while the photographer maintains the same camera position. The photo is taken and is illustrated in Fig. 5.53. Here we are evaluating the relationship of the maxillary incisal edges to the vermillion border of the lower lip. Ideally, we would like to see the incisal edges just slightly inside the vermillion border of the lower lip. Again, much like confirming the vertical position of the incisal edge, the horizontal position can be verified by taking a photograph of the patient from a horizontal position. We do not have a photograph illustrating the patient and photographer position, but if we review

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Fig. 5.50  Digital photography: photographer and patient position—“Repose” or “rest” Fig. 5.51 Digital photography: “repose” photo illustrating the amount of display of the maxillary central incisor

Fig. 5.45, the “horizontal smile view” photo (lower left photo) shows the relationship of the maxillary incisal edge to the lower lip. Here we would like to see the maxillary incisal edge positioned just inside the vermillion border of the lower lip. The exception is the class II skeletal patient where the mandible is retruded, and thus the horizontal photos as described above will illustrate the maxillary incisal edges are beyond the vermillion border of the lower lip. In these cases, orthodontic treatment should be considered as a means to establish a better horizontal incisal edge relationship. Depending on the severity of the skeletal relationship, post orthodontic treatment may still produce a better incisal edge to lip relationship.

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Fig. 5.52  Digital photography: photographer and patient position—“tip-down smile”

Fig. 5.53 Digital photography: “tip-down smile” photo illustrating the relationship of the maxillary incisal edges to the inner vermillion border of the lower lip

In this chapter, we have covered the basic understanding to obtain correct diagnostic records which include perfect impressions, facebow transfer, and centric bite record. In addition, digital photographs are also needed to complete the diagnostic data. With all this information now in the dentist’s hand, the treatment planning process can begin by first evaluating the diagnostic models along with the photographs. We will go into much detail in Chap. 8.

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References 1. House MM (1957) The relationship of oral examination to dental diagnosis. J Prosthet Dent 8(2):208–219 2. McKee JR (1997) Comparing condylar position repeatability for standardized versus nonstandardized methods of achieving centric relation. J Prosthet Dent 77:280–284. https://doi. org/10.1016/S0022-3913(97)70185-9 3. McKee JR (2005) 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 94:389–393. https://doi.org/10.1016/j. prosdent.2005.06.012 4. Ballastreire MCFF, Carmo GG, Fantini SM (2015) Reliability of the anterior functional device in recording the centric relations of patients with posterior tooth loss. J Prosthet Dent 114(4):560–565. https://doi.org/10.1016/j.prosdent.2014.12.025 5. Chee WWL, Donovan TE (1992) Polyvinyl siloxane impression materials: a review of properties and techniques. J Prosthet Dent 68(5):728–732. https://doi.org/10.1016/0022-3913(92)90192-D

6

Incisal Edge Position: Its Importance to Aesthetics and Function

“Try to be a rainbow in someone’s cloud” Maya Angelou

Contents 6.1  Discussion 6.2  Central Incisor Anatomy Review 6.3  Incisal Edge Wear 6.4  Incisal Edge-Aesthetic Components 6.5  Incisal Edge-Functional Components 6.6  Predictable Incisal Edge Design References

6.1

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Discussion

When one thinks about aesthetics, we always associate it with the maxillary anterior teeth. Knowing this, there is an emphasis for most dentists to only focus on these teeth while not paying any attention to the remaining dentition. This by no way implies a lack of moral or ethical conscience of a dentist, but what it does state is that dentists unintentionally ignore other aspects of a patient’s dentition possibly because of ignorance (they do not know what they do not know), or the patients have no symptoms associated with worn anterior dentition. This fact could not be further from the truth especially when it is related to incisal edges. Over the years, I have seen and continue to see many patients with compromised incisal edges. During the discussion of expressing concerns about the worn anterior dentition, the patient may respond with the following comments: “Why didn’t my last dentist express the same concerns as you do?” “My previous Dentist told me that this was a sign of aging and was normal.” “I was told that my teeth are worn down because the last dentist told me that I grind my teeth.” These examples are true and I am sure that you may have come across the same excuses or you may actually believe in some of those reasons for © Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_6

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ignoring incisal edge wear. Regardless of what you believe, it is the authors’ opinion that signs of anterior wear should not be ignored just because there are no symptoms. Remember, signs precede symptoms, and it is our moral and ethical duty to explain the implications to our patients and let them decide if they choose to solve these problems, or not. If they choose not to, then again our duty is to explain the implications of not pursuing solutions to those problems. Worn dentition does not discriminate with age, gender, or location in the mouth, but trends show more wear with increased age possibly due to diet, medical concerns (GERD, etc.) and parafunction [1]. Specifically, anterior tooth wear is significant in all populations, and this usually does not become an issue for patients unless the treating dentist makes it a priority. This can also be compared to periodontal disease as this also does not discriminate with age and gender, but the relevance here is the timing of the diagnosis. Not diagnosing periodontal disease earlier in life can have profound impact on a patient as they get older with the risk of infection and tooth loss. Similarly to periodontal disease, anterior tooth wear (although not symptomatic in all cases)

Fig. 6.1  Incisal edge wear at two different age groups Fig. 6.2  Patient example of attractive smile

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needs to be addressed earlier than later as the implications can compromise patient’s function over time. Figure  6.1 illustrates two patients that are 35  years apart. The patient on the left side is the younger patient, but the way he has destroyed his teeth, he would appear much older (dentally). It is fair to predict that if left untreated, the younger patient may end up in a similar situation as the older patient. Discussing these issues with a younger patient (and/or parents) may be more comfortable as the treatment to treat the problem may be less invasive and more cost effective. Figure 6.2 is a perfect example of an attractive smile that appears to be healthy and normal. Figure 6.3 illustrates the same patient but viewing only the maxillary anterior teeth. Here, the right central incisor appears slightly shorter than its neighbor (#2.1 or #9) along with having a slight chip at the distal incisal edge. Further investigation in Fig.  6.4

Fig. 6.3 Retracted maxillary anterior teeth of the same patient showing discrepancy with central incisal edges

Fig. 6.4  View of the same maxillary central incisors illustrating lingual incisor wear

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illustrates the lingual side of the maxillary central incisor. Here changes to the lingual incisal edge of tooth #1.1 (#8) illustrate wear, and thinning of the enamel, and more of a jagged edge from mesial to distal. As mentioned earlier, when changes occur to one tooth, then the opposing tooth may also be affected. In this same patient case, Fig. 6.5 shows lower anterior teeth somewhat normal, but Fig. 6.6 tells a different story. Here the lower anterior teeth show signs of wear into the dentin which makes the incisal edges thicker than usual. The conversation would be much different with the same person later on in life as their condition worsens (and signs would have led to symptoms), and the treatment most likely may be more complex, invasive, and costly. Figure 6.7 illustrates this example of a patient who was never told that there was an occlusal problem that was causing the deterioration of her teeth. Here the image shows the retracted teeth apart with the presence of incisal wear (maxillary central incisors, and lower anterior teeth), and tissue recession. In addition, Fig. 6.7 also shows the gingival margins. It is clear that there is no symmetry of the gingival margins of the maxillary anterior teeth, as well as the mandibular teeth too. When you see this pattern Fig. 6.5 Retracted mandibular anterior teeth of the same patient

Fig. 6.6  Lingual view of the same mandibular anterior teeth showing incisal wear

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Fig. 6.7  Anterior retracted view of patient with signs of occlusal disease

Fig. 6.8  Occlusal views of the same patient with signs of occlusal disease

of the lower gingival margins, it is an indication that lower teeth are wearing and passively erupting to maintain contact and function. The lower incisal plane is very inconsistent as compared to the incisal plane seen in Fig. 6.5. Remember, this patient was never told of these issues, and now is willing to consider other solutions. Figure 6.8 illustrates the occlusal views of the same patient. Please note the lingual inclination of the maxillary central incisors as well as the mandibular crowding. It is understood in this case that she has a restricted envelope of function which is causing her teeth to change structurally over time. Figures 6.9 and 6.10 illustrate the structural changes that have taken place over time. Needless to say, this patient was frustrated with the fact that no one expressed the urgency to treat the problem earlier on.

6.2

Central Incisor Anatomy Review

In Chap. 2, the anatomy of several anterior teeth including the maxillary central incisor was described in detail. Figure 6.11 depicts all the surfaces of the maxillary central incisor. On the facial side, the maxillary central incisor has three planes on

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Fig. 6.9  Close-up of maxillary anterior teeth of the same patient illustrating the extent of the wear

Fig. 6.10  Close-up of mandibular anterior teeth of the same patient illustrating the extent of the wear

the labial side: emergence, facial, and incisal one-third. The first plane, the emergence, originates from the CEJ and extends outwards from the gingival margin. The second plane, facial, extends from the emergence and maintains a flat plane which is supported by the upper lip position. Finally, the incisal one-third takes a very slight inward position as compared to the second plane, and is supported by the lower lip position. For example, hold your mouth at rest (lips touching, teeth slightly apart), and take your index finger and lightly press the middle of your lower lip— you should feel your lower lip touch the incisal one-third of your maxillary central

6.2  Central Incisor Anatomy Review

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Fig. 6.11  Dental anatomy of maxillary central incisor

Fig. 6.12  Dental anatomy of mandibular central incisor

incisor. On the lingual side, the anatomy continues from the incisal edge position, and follows a concave pattern (the lingual contour) and then convex (the cingulum) toward the CEJ. This lingual contour is responsible for phonetics and anterior guidance (or coupling), and represents part of the functional aspect of this tooth [2]. The phonetics of the lingual side will be discussed in more detail in Chap. 7. In addition to the lingual contours of the maxillary central incisor, function is aided by the contact of the lower anterior teeth. The incisal edge of unworn, healthy lower anterior teeth has a defined flat surface that is designed to engage on the lingual surface of the maxillary anterior teeth. Figure 6.12 illustrates the mandibular incisor with the facial-incisal line angle creating the ideal contact point. In addition, this same

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contact point must also engage with the entire lingual surface of the maxillary incisors. Figure 6.13 illustrates this point. There are many elements to a beautiful and attractive smile including symmetry of the face and lips, soft tissue display, and size and shape teeth. Of those elements, the maxillary anterior teeth play a significant part. The smile begins at the midline of the face and extends laterally with the maxillary central incisors being the focal point. Figure 6.14 illustrates where to start evaluating a smile. From there the lateral incisors are slightly shorter in length followed by the canine teeth which ideally are at the same length as the central incisors. The length of the central incisor starts at the gingival margin and ends at the incisal edge. The maxillary central incisal edge position is one of the most significant (and underrated) parts of this tooth. From an aesthetic perspective, the incisal edge position carries the burden of being the vertical and horizontal end points of a central incisor, as well as being the outer limit for function. It can determine how a smile is perceived based on where the incisal edge is located. An incisal edge that is too far facial or tipped too lingual will change the perception of the length of the central incisor. For example, Fig.  6.15 represents maxillary central incisors at two different angles. When viewing from the facial angle, the maxillary central incisor that is angled toward the facial will appear slightly shorter as compared to the incisor that is more upright. The point here is if you are attempting to alter the incisal edge position, you must consider both the vertical and horizontal components at the same time. For example, if you shorten a maxillary central incisal edge restoration, the edge becomes thicker horizontally (facial-lingual). As a result, you will then need to adjust from the facial to maintain the incisal edge at the same visual reference. On the other hand, central incisor(s) that are prematurely worn can appear to age a person. Besides trauma, there are several other causes of incisor (both maxillary and mandibular) tooth wear. Some of the

Fig. 6.13  Mandibular central incisor edge contact with the lingual surface of the maxillary central incisor

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Fig. 6.14  Evaluation of a smile begins at the midline and moves outward to the posterior teeth

Fig. 6.15  Perceived incisal edge positions at two different axial inclinations of the maxillary central incisor

more common ones include chronic parafunction, poor occlusion, and possible compromised airway. As mentioned earlier, central incisor edges can wear over time, resulting in a shorter tooth. Not only does the incisal edge become thicker, but also the tooth passively erupts to maintain the incisal edge position to maintain function. You can see this by paying attention to the gingival margins of the teeth that have passively erupted. For example, lower incisor teeth that have incisal wear will have gingival margins that are more incisal as compared to other teeth that have less wear. In a cross-sectional view, anterior teeth are thicker toward the CEJ and having said this, as the wear continues, the incisal edge becomes wider (facial-­lingual). As worn teeth passively erupt, the muscle contractions of the soft tissues (lips) maintain the incisal edge in place. This adaptive process results in a thicker incisal edge. Over time, musculature associated with the tongue and lips causes the position of these teeth to change toward the lingual side. As the cycle continues the envelope of

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function becomes more and more restricted which in turn creates more stress in the masticatory system. Until intervention is made by a restorative dentist, this cycle continues. This process is discussed in more detail in Chap. 3. However, Fig. 6.16 illustrates this point. If you see irregular gingival margins in the lower anterior teeth, then you can be assured that there is passive eruption to maintain function, pay attention to the incisal edges as they may appear thicker and/or have exposed dentin. When restoring anterior teeth (composite, crown, and/or veneer), much attention is focused on the preparation design. This is critical as the preparation design will dictate how the technician creates the final restoration. In the preparation design, the most important area that is overlooked is at the incisal edge. From many conversations with technicians, the overwhelming majority state that the incisal one-third is usually underprepared (from the facial side). If that is the case, then the technician will produce a restoration that may be too thick on the facial and/or lingual sides of the incisal edge. Figure  6.17 depicts an example of

Fig. 6.16  Incisal edge changes due to changes in position over time

Fig. 6.17  Inadequate preparation reduction at the incisal one-third

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inadequate preparation in the incisal one-third. What are the ramifications of this accepting this process? The restoration’s incisal edge will have a different relationship with the lips and lower anterior teeth (during functioning movements). The patient may feel the incisal edge is too thick or long, and may comment on the phonetic component. There is also a risk of this tooth changing position over time due to the excessive porcelain interacting with the soft tissues (as mentioned earlier).

6.3

Incisal Edge Wear

The incisal edges of anterior teeth are often overlooked during an examination unless there is significant trauma or disease. Oftentimes, what is told to patients is that any wear or damage can be attributable to parafunction, such as clenching or grinding, or a sign of aging. There is some truth to this, but keep in mind that there may be other factors including poor airway issues and occlusion. The next time you pick up your dental journals, look at an aesthetic case, review the before and after photos, and pay attention to the mandibular incisal edges. In these same journals, only the maxillary teeth are restored, but the mandibular teeth appear unchanged. The point here is that if you alter the shape of the maxillary anterior teeth, and not treat the lower anterior teeth, then you have possibly altered the function for the patient. This may be acceptable in the short term, but long-term consequences may result in failure or damage to either the restorations or the opposing dentition. Figure 6.18 illustrates an example of treatment that was rendered in the past that has failed along with continued destruction of the dentition. Here there is moderate destruction of the anterior teeth, and occlusal views in Fig. 6.19 help illustrate this in more detail. Here you can clearly see the amount of incisal wear along with posterior damage (#3.4, #2.5). In Chap. 3, we discussed the concept of the “envelope of function,” and in this case, this patient’s envelope of function was not only restricted,

Fig. 6.18  Patient example illustrating extensive damage to anterior teeth

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Fig. 6.19  Maxillary and mandibular occlusal views of the same patient

Fig. 6.20  Close-up view of maxillary anterior teeth

but the addition of parafunction also contributed to the destruction of his teeth. Figures 6.20 and 6.21 illustrate the extent of destruction of both maxillary and mandibular teeth. There are many of your own patients that resemble incisal wear patterns similar to those illustrated here. Treating these wear patterns requires diligent planning using mounted models in centric relation and working out the functional results on the models first before implementing them in your patient.

6.4  Incisal Edge-Aesthetic Components

137

Fig. 6.21  Close-up view of mandibular anterior teeth

6.4

Incisal Edge-Aesthetic Components

The incisal edges of both maxillary and mandibular anterior teeth play an important role with respect to both function and aesthetics. Function relates to phonetics, mastication, and occlusion. The significance of phonetics will be discussed in more detail in Chap. 7; enunciation of sounds and words is accomplished with airflow with collaboration of the maxillary central incisors, tongue, and lips. Mastication begins with tearing the food by using the incisal edges of both mandibular and maxillary anterior teeth. Occlusion is the relationship of the mandibular and maxillary teeth while in contact as well as how the anterior teeth protect the posterior teeth during functional movements [3]. Aesthetics relates to the appearance of anterior teeth with respect to color, size, and position. Anterior teeth that are ideal in size are complemented based on length-to-width ratios and golden rule of proportion [4, 5]. The position of the anterior teeth is related by the arch form and support of soft tissue—specifically muscles (lips, tongue, buccinator). Appearance is a very subjective area but for the most part we associate appearance with color, brightness, and alignment. In addition, the gingival margin (position and display) also plays a significant role in the perception and overall appearance of the anterior teeth. In most cases, the perceptions of what is attractive to a patient as compared to any dental professional can vary, but the patient’s opinion should be taken as priority opinion before making any clinical decisions [6, 7]. It is important to remember that both function and aesthetics are connected to each other—that is, over time, a compromised function can create a poor aesthetic outcome (wear, recession, cracks, chipping, etc.). If a patient is seeking an aesthetic change, then it is the responsibility of the dentist to understand the patient’s existing function before recommending any aesthetic treatment. Sometimes, solving an aesthetic problem can indirectly produce a functional problem. This can lead to dentist

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and patient dissatisfaction, frustration, and more importantly risk of failure to the completed restorations. On the other hand, solving a functional problem may involve restoring anterior teeth to help improve function. In this chapter, we discuss the importance of the maxillary and mandibular incisal edge with respect to aesthetics and function.

6.5

Incisal Edge-Functional Components

Both maxillary and mandibular incisors have important duties related to ­function. These include mastication, phonetics, and occlusion. Mastication is the mechanical grinding of food into smaller pieces also known as chewing. This is the first step in digestion, and proper chewing of food creates more surface area in the food bolus and leads to better breakdown by enzymes. Better breakdown of bolus of food allows more nutrients to be absorbed and stored. Mastication begins with tearing of food into smaller pieces which then is transferred to the posterior teeth for maximum breakdown of the food bolus. Once the breakdown of the food bolus has been achieved, the process of mastication is completed with swallowing. This has been described as a three-stage process. Stage 1 refers to the process of the front teeth moving the bolus to the premolars/molar. Stage 2 represents the chewing cycle that reduces particle size. The chewing cycle is dependent on the size and consistency of the food. The final stage represents the pre-swallowing mechanism where the food bolus is transported to the back of the mouth over the tongue. This mechanism can change when teeth are partially or completely missing. The maxillary and mandibular incisors along with the canines are primarily used to tear food just before stage 1. Regardless of the thickness of the incisal edge this function is not compromised. However, having less posterior teeth will certainly compromise stage 2 phase [8]. The second function of the maxillary incisal edge is related to phonetics. Chapter 8 is dedicated for explaining how the design of anterior teeth impacts the phonetics. However, this chapter will focus on how the incisal edge position relates to phonetics. The pronunciation of letters “F” and “V” involves the tongue, lips, and the position of the incisal edge. When sounding “F” words, the mandible slightly opens allowing the lower lip to engage with the incisal edge. For example, counting out loud from “51” to “55” produces a crisp “F” sound as the inner vermillion border of the lower lip barely touches the maxillary central incisal edge. When restoring the incisal edge that is not in the correct position, the patient will have to adjust the lower lip to compensate for this difference. If the incisal edge is too far (facial) or backward (lingual) the lip must move in the same direction, respectively, to create the ideal relationship to create “F” sounds [9, 10]. Over time, a patient may complain of a tired lower lip. To avoid this from occurring, the incisal edge should be confirmed vertically and horizontally in the provisional stage—using photography (“e” smile, “repose,” and “tip down”) and phonetic testing. Altering the incisal edge position correctly will allow the patient to feel comfortable and sound normal. This information can be easily transferred to the technician with predictability (see Chap.

6.6  Predictable Incisal Edge Design

139

9), resulting in a restoration with an incisal edge that can be confirmed, the mandibular incisal edges. The maxillary and mandibular incisal edges have an important function to occlusion. The mandibular central incisal edge serves as the stable holding contact to the lingual surface of the maxillary central in centric relation. The contact is located on the “leading edge” of the mandibular incisor. Following this contact, as the mandible protrudes, the lower incisal edges follow the contours of the lingual surfaces of the corresponding maxillary incisor causing disclusion of the posterior teeth. There should be complete disclusion of the posterior teeth when the lower incisal edge meets the upper incisal edge. Although the mandible can continue past the maxillary incisal edge, this is not a normal functioning movement. The maxillary incisal edge is the end point of function as can sometimes be termed the “invisible fence” during functioning movements. Upon closure, the mandibular incisal edges do not collide past the maxillary incisal edge, but instead close just inside the maxillary incisal edge. In a clinical setting, when restoring anterior teeth, you can have the patient sit upright, place articulating paper in the anterior area, and ask the patient to open and close much like chewing. If either the maxillary or the mandibular incisal edge is too thick, you may see articulating paper showing rubbing of the facial surfaces of the lower incisors. This description has more to do with the concept of the functional elements of the movements of the mandible with the anterior teeth, sometimes referred to as the envelope of function or chewing patterns.

6.6

Predictable Incisal Edge Design

There is a better, more predictable way to design and create anterior restorations that require little adjustments and provide a comfortable, natural result for your patient. The key to this process is to start by understanding where the incisal edge is positioned with respect to the soft tissue and function. As mentioned earlier in this chapter, the incisal edge must rest comfortably with support of the upper and lower lip. The incisal edge position has both vertical and horizontal positions. In Chap. 5, we outlined the diagnostic records which included diagnostic models, facebow transfer, centric relation, and digital photography. Using digital photography, we can determine the incisal edge position. To determine the vertical position, the “repose” and “E smile” photographs are used. The “repose” photo is used as a guide as to how much incisal edge is revealed at rest. As we age, we tend to show less incisal edge [11–13]. Figure 6.22 illustrates the reasoning behind this photograph, the point being the importance of using both photos to confirm the incisal edge in the vertical position. If you are not sure by viewing just the “repose” photo, then using the “E smile” photo will confirm whether you need to modify the incisal edge position. Figure 6.23 illustrates the E smile photo and the parameters of where the maxillary incisal edge lies between the inferior border of the upper lip and the superior border of the lower lip. Here, the incisal edge would be ideal between 50% and 70% of these parameters [9]. To determine the horizontal position, the “tip-down” and “lateral smile” photographs are used. What we are looking for is the maxillary

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Fig. 6.22  Repose position to determine the vertical position of the maxillary incisal edge. (Vig RG, Brundo GC. J. Prosthet. Dent., 1978 May: 39(5):502–4)

Fig. 6.23  E smile position to determine the vertical position of the maxillary incisal edge. (Pound E, Prosth. Dent., 2006 Jan:95(1):1–9)

incisal edges to fall just inside the vermilion border of the lower lip [14]. Figure 6.24 illustrates the relationship of the incisal edges to the inner vermillion border of the lower lip. This will give you an idea of whether you have room to change the horizontal position of the incisal edge. Figure  6.25 illustrates three different patients with variations in their respective hard and soft tissues. Patient “A” has acceptable vertical and horizontal incisal edge position; the incisal edge position of Patient “B” is deficient vertically, and the horizontal acceptable, but may suggest orthodontic

6.6  Predictable Incisal Edge Design

141

Fig. 6.24  Tip-down and lateral smile position to determine the horizontal position of the maxillary incisal edge. (Passia N, Blatz M, Strub JR. Eur J Esthet Dent 2011 Autumn;6(3): 314–27)

a

b

c

Fig. 6.25  Three patients with different incisal edge positions. Photographs used to verify both the horizontal and vertical positions of the maxillary central incisal edge

moving of the anterior teeth in the facial direction (due to the extra horizontal space available); for Patient “C” although the “repose” photo does not show any maxillary incisal edge, the “E smile” photo confirms the vertical position of the maxillary central incisors. Horizontally, the maxillary incisors are tipped lingual, and could benefit from orthodontic movement toward the facial side. Once you begin to use this method to identify the ideal location of the incisal edge, it will become the normal method for you.

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References 1. Schierz O, Dommel S, Hirsch C, Reissmann DR (2014) Occlusal tooth wear in the general population of Germany: Effects of age, sex, and location of teeth. J Prosthet Dent 112(3):465–471. 2. Broderson SP (1978) Anterior guidance—The key to successful occlusal treatment. J Prosthet Dent 39(4):396–400. 3. Vence BS (2007) Predictable esthetics through functional design: the role of harmonious disclusion. J Esthet Restor Dent 19(4):185–191; discussion 192. https://doi. org/10.1111/j.1708-8240.2007.00096.x 4. Tjan AH, Miller GD, Josephine GP (1984) Some esthetic factors in a smile. J Prosthet Dent 51(1):24–28. 5. Mack MR (1996) Perspective of facial esthetics in dental treatment planning. J Prosthet Dent 75(2):169–176. 6. Pinzan C et al. (2020) Comparison of gingival display in smile attractiveness among restorative dentists, orthodontists, prosthodontists, and laypeople. J of Prosthetic Dent. 123(2):314–321. 7. Rodriguez-Martinez A, Vicente-Hernandez A, Bravo-Gonzalez LA (2014) Effect of posterior gingival smile on the perception of smile esthetics. Medicina Oral Patología Oral y Cirugia Bucal: e82–e87. 8. van der Bilt A, Engelen L, Pereira LJ, van der Glas HW, Abbink JH (2006) Oral physiology and mastication. Physiol Behav 89(1):22–27. 9. Pound E (2006) Utilizing speech to simplify a personalized denture service. J Prosthet Dent 95(1):1–9. 10. Pound E (1966) The mandibular movements of speech and their seven related values. J Prosthet Dent 16(5):835–843. 11. Vig RG, Brundo GC (1978) The kinetics of anterior tooth display. J Prosthet Dent 39(5):502– 504. https://doi.org/10.1016/S0022-3913(78)80179-6 12. Drummond S, Capelli J (2016) Incisor display during speech and smile: age and gender correlations. Angle Orthod 86(4):631–637. https://doi.org/10.2319/042515-284.1 13. Pithon MM, Matos VO, da Silva Coqueiro R (2015) Upper incisor exposure and aging: perceptions of aesthetics in three age groups. J World Federat Orthod 4(2):57–62. https://doi. org/10.1016/j.ejwf.2015.02.002 14. Passia N et al. (1978) Is the smile line a valid parameter for esthetic evaluation? A systemic literature review. Eur J Esthet Dent. 6(3):314–327.

7

Phonetics: How to Design with Phonetics in Mind

“The greatest teacher failure is…we are what they grow beyond. That is the true burden of all masters” Yoda, Star Wars Episode 8

Contents 7.1  Discussion 7.2  Manner of Articulation 7.3  Place of Articulation 7.4  Phonetics in Dentistry 7.5  “F/V” Sounds 7.6  “T/D” Sounds 7.7  “S” Sounds References

7.1

 143  144  145  147  148  148  149  152

Discussion

Language has been present for thousands of years. It has evolved (and continues to evolve) throughout civilizations and today it is an integral part by which culture, religion, and an individual’s nationality are described. Regardless of culture, religion, or nationality, communication begins at birth. During this time, babies have the ability to discriminate sounds of adults by keeping statistics on the languages spoken at home. As babies continue to develop toward age of 1, they become better at discriminating their native sounds, but lose the ability to discriminate other language sounds. This junction is referred to as the “critical phonetic period.” Prior to this phonetic period, babies are able to keep statistics of other languages. Babies cry to signal fear, hunger, or sensory overload. Several months after birth continued brain development allows pronunciation of sounds like “da-da” and “ba-ba.” As development continues, pronunciation of early words begins such as “mama” and “dada” [1]. These are the developments through which phonetics plays a role in the development of language. It is one of the observations that during early © Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_7

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childhood children learn to pay much attention to the mouths of their respective parents. This helps the child to learn to put sounds together to form a word. For this discussion, we will only focus the subject of phonetics to the English language [2]. According to Merriam-Webster, phonetics is defined as “the system of speech sounds of a language or group of languages.” This can be subdivided into three categories: articulatory, acoustic, and linguistic phonetics. Articulatory phonetics is associated with the physical mechanism associated with producing language, in other words how sounds of language are coordinated with physical movement of the chest, neck, and head parts. Acoustic phonetics explores the physical properties of sound, such as frequency, amplitude, and duration. Linguistic phonetics describes the combination of sounds to produce syllables, words, and sentences [3, 4].

7.2

Manner of Articulation

Figure 7.1 (taken from Encyclopedia Britannica) illustrates all the landmarks associated with articulatory phonetics which include landmarks of articulation to produce consonant sounds. These sounds are produced by airflow (of various pressure) from the lungs through the vocal cords while interacting with both soft and hard tissues from the pharynx to the lips. An understanding of airflow (“manner of

Fig. 7.1  Anatomy of the oral cavity with landmarks outlining boundaries for sound production

7.3  Place of Articulation

145

Table 7.1  Manners of articulation Description of airflow from lungs Completely blocked for a period, then released Constricted but not blocked Initially blocked, but then finishes with restricted flow Nasals Through the nose Laterals Through the sides of the tongue Approximants Articulators are close to one another “Manner” Stops Fricatives Affricates

Letter sounds “p,” “b,” “t,” “d,” “k,” “g” “f,” “v,” “s,” “z,” “h” “C,” “J” “m,” “n” “l” “j,” “w,” “r”

articulation”) and its interaction (“place of articulation”) with the soft/hard tissues is important to appreciate how consonant sounds are produced. Consonant sounds of English are classified based on both “manner of articulation” and “place of articulation.” The term “manner of articulation” describes how air breath is used at the place of articulation. There are five “manners” related to the oral cavity, and one to the nasal cavity. Table 7.1 illustrates the description of the airflow for each “manner,” with corresponding letter sounds. To pronounce the letter “p,” the lips come together, and slight pressure is collected before it is pushed and released making the sound “p.” A similar mechanism exists for letters such as “b,” “t,” “d,” “k,” and “g.” Here the airflow is completely blocked and then released, creating the corresponding letter sound. In other letters such as “s,” “f,” and “v,” airflow is constricted but not blocked. Other sounds also formed from different pathways of airflow and have respective “manners” as described in Table 7.1 [4].

7.3

Place of Articulation

The term “place of articulation” refers to the location in the mouth where the sound is produced. Table 7.2 refers to the landmarks where specific sounds are produced in areas of both the oral pharynx and oral cavity. Here, the “places of articulation” are listed starting with the lips (bilabial) and ending with the vocal cords (laryngeal). As mentioned when referencing Table 7.1, the sound of the letter “p” requires airflow to build pressure while both lips are together. When the air is released, the lips are the point of articulation to make the letter sound “p.” Thus, airflow and point of articulation are the foundations that lead to words and communication. Out of the seven “places of articulation,” there are only two, “labiodental” and “interdental” that are related to the interaction of both soft tissue (lower lip and tongue) and anterior teeth, specifically the maxillary central incisors. When restoring anterior (mandibular and/or maxillary) teeth, the restorative design needs to be respected so that the labiodental and interdental places of articulation remain constant and unchanged. The “alveolar” place of articulation does provide significant information about the cervical lingual design of the maxillary incisors by having the tongue engage slightly behind these teeth during “S” sounds. It is important to note that in order for “S” sounds to be articulated, there needs to be enough clearance between the

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mandibular and maxillary anterior teeth, as well as enough lateral space in the hard palate for the tongue to rest. Table 7.3 combines both manner and place of articulation, and the highlighted areas are those pertaining to our discussion in this chapter. Table 7.2  Place of articulation

Table 7.3  Consonants sounds with “manner” and “place” of articulation

7.4  Phonetics in Dentistry

7.4

147

Phonetics in Dentistry

Phonetics in dentistry is mostly discussed during fabrication of complete upper and lower dentures. One of the goals is to create a denture that has great retention and stability, but also provide function for the patient, both occlusally and phonetically. The fabrication of dentures begins with using wax rims designed from preliminary casts. Once retention is conformed, the wax rim is modified for aesthetics and phonetics. For aesthetics, the wax rim is trimmed for ideal soft tissue support while also addressing the smile by showing how much wax is displayed during the smile poses. The trimmed wax will determine the setup of the new teeth. In addition, taking digital photos of the E smile, repose, tip down, and profile smile poses will help the dentist decide whether to trim the wax rim further to create ideal aesthetics. The trimmed anterior wax rim will serve the purpose of helping the laboratory technician to determine where to place anterior teeth, both vertically and horizontally. The maxillary occlusal plane should mirror the shape of the lower lip during a smile pose, and the interpupillary distance provides a dimensional reference for the combined width of maxillary anterior teeth (from canine to canine line angles). The phonetics verification takes place when the wax rim is trimmed, and the place of articulation is focused on the labiodental, interdental, and alveolar areas [5]. The patient is asked to create consonant sounds with both wax rims in place by asking the patient to do the following: 1 . Count out loud the following numbers: “31–37,” “51–57,” “61–67.” 2. Say the letter “m” and word “Mississippi.” If counting (“31–37,” “61–67”) does not produce crisp, clean sounds, the “interdental” and “alveolar” place of articulation is compromised. If the sound is “slurred,” then it most likely indicates that wax on the anterior palate side of the rim is too thick. However, if there is “whistle” sound, then there is too little wax allowing too much air to escape [6]. Likewise, if counting 51–57, pay attention to how the inner vermillion border of the lower lip engages with the upper anterior wax rim. If the maxillary denture rim is too far forward, then the lower lip will need to reach over and touch the anterior rim. The lower lip moves to the lingual side of the upper rim, creating more of a “fitty” sound. On the other hand, should the anterior segment of the upper rim be too far lingual, then the only way the patient can get the lower lip to engage is to open the mandible further. This is not a natural phonetic movement when counting 51–57—patient may not look comfortable. When the anterior segment of the maxillary wax rim is correctly trimmed (both the vertical and horizontal planes), the vermillion border of the lower lip should barely engage and produce clean and crisp “f” sounds. After confirming both wax rims, teeth are set and returned for try in. The wax try-in appointment is similar to the appointment previously described, but here it is used to confirm aesthetics, function, and phonetics. This same process can also be used when restoring dentate patients, especially in the anterior regions. Instead of modifying wax rims, mounted models are modified to successfully design maxillary central incisors. Using digital photography, centric

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bite record, semiadjustable articulator, and dental charting, a disciplined approach (DOTA—Chap. 8) provides the dentist with a best guess scenario that is ideal until confirmed intraorally. In Chap. 10, we verify the anterior teeth in the provisional stage. Here, aesthetics, function, and phonetics are confirmed in the provisional restorations in a similar fashion to the denture process. As mentioned earlier, the maxillary central incisal edge position is fundamental to proper phonetics (“f/v” sounds), aesthetics (E smile, repose, tip down, and lateral smile), and function (end point of anterior guidance). The patient is asked to return back to the office (a few days later) to confirm the design and make any changes necessary to improve the aesthetics, phonetics, and function. Prior to checking the phonetics, make sure that the functional and aesthetic elements have been completed first. The reason is that in most cases, addressing these two elements will provide a favorable phonetic result. The aesthetic component is verified using digital photos (E smile, repose, tip down, and horizontal smile) and the patient’s input. Any alteration in the incisal edge needs to be addressed in a vertical and horizontal manner. For example, should you need to shorten the incisal edge of a maxillary anterior provisional restoration, then the incisal edge is not only now shorter, but also thicker (facial-lingual). The patient may now feel that the incisal edge is too protruded. To maintain proper phonetics, the incisal facial one-third will need to be adjusted toward the lingual side as to bring “in” the incisal edge back to the original position. The patient will feel more comfortable, and this will not compromise the phonetics. The functional element is finalized using bimanual manipulation and adjusting for any occlusal and eccentric interference. The phonetic verification determines and/or confirms the lingual contours of the maxillary anterior teeth. Here the phonetic tests comprise three parts: “F/V,” “T/D,” and “S” sounds.

7.5

“F/V” Sounds

This phonetic test is to verify the incisal edge of the maxillary central incisor. The place of articulation is “labiodental”—lower lip to the maxillary anterior teeth. During this test, the mandible slightly opens, and the lower lip is underneath the maxillary central incisor. When the patient is asked to count from “51 to 55,” we would like to see the lower lip just touch the incisal third as a rule. The ideal sound should be clean and crisp. See Figs. 7.2 and 7.3.

7.6

“T/D” Sounds

This phonetic test is to verify the shape and size of the cingulum. The place of articulation is “alveolar/interdental”—tip of the tongue just behind the maxillary teeth. During this test, the lower lip drops, and the tongue touches lingual side of the restoration, near the cingulum. When counting out loud from “31 to 35,” please pay attention to the sounds and determine if any alterations are needed. See Figs. 7.4 and 7.5.

7.7  “S” Sounds

7.7

149

“S” Sounds

This phonetic test is designed to test the lingual contours of the maxillary anterior teeth. The place of articulation is “palatal”—tongue near the hard palate. During this test, the lower lip and tip of the tongue drop slightly allowing a small amount of space between the lingual surfaces on the maxillary anterior teeth. When counting

Fig. 7.2  Phonetics: Maxillary incisal edge position determines “F” and “V” sounds

Fig. 7.3  Phonetics: Tongue and lower lip change positions and use maxillary incisal edge to create “F” sounds

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Fig. 7.4  Phonetics: Lingual contour of the maxillary central incisor determines the quality of “S” sounds

Fig. 7.5  Phonetics: Tongue and lips change position and use the lingual contour to create “S” sounds

out loud (“61–66”), pay attention to the quality of the sound. If the lingual contours of the maxillary teeth are too shallow, then too much air will escape, giving more of a whistle sound. On the other hand, should the contours are too thick, then expect more of a slurring sound. See Figs. 7.6 and 7.7. It is not common to apply phonetic testing to restorations, but when you understand the components that create sound in the oral cavity, then it makes sense to

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Fig. 7.6  Phonetics: Maxillary central incisor cingulum shape determines “T” and “D” sounds

Fig. 7.7  Phonetics: Tongue moves upward toward cingulum to create “T” and “D” sounds

respect and appreciate how contours and position of teeth can influence phonetics. As mentioned earlier, complete dentures were the introduction to the importance of phonetics as the goal was to set acrylic teeth in wax and not compromise the aesthetics, function, and phonetics. These same principles used in complete dentures can be applied to restoring anterior teeth.

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References 1. Kuhl PK, Tsao F-M, Liu H-M (2003) Foreign-language experience in infancy: effects of short-­ term exposure and social interaction on phonetic learning. Proc Natl Acad Sci 100:9096–9101 2. Houston DM, Horn DL, Qi R, Ting JY, Gao S (2007) Assessing speech discrimination in individual infants. Infancy 12:119–145 3. Boyanova M (2002–2018) English Phonetics. http://www.studyenglishtoday.net/englishphonetics.html 4. Szczegielniak A Introduction to lingual theory. Phonetics: The Sound of Language. https:// scholar.harvard.edu/files/adam/files/phonetics.ppt.pdf 5. Pound E (1977) Let /S/ be your guide. J Prosthet Dent. 38(5):482–489. 6. Pound E (2006) Utilizing speech to simplify a personalized denture service. J Prosthet Dent. 95(1):1–9.

8

Diagnosis and Treatment Planning

“Yesterday is gone. Tomorrow has not yet come. We only have today. Let us begin.” Mother Theresa

Contents 8.1  F  unctional Diagnosis 8.2  S  tructural Diagnosis 8.3  D  iagnostic Occlusal Analysis

 159  168  170

One of the essential roles of any healthcare provider is to provide treatment based on a correct diagnosis. Dentists around the world devote time treating dental disease and structural defects and replacing missing teeth. However, what we do not know is how much time is spent diagnosing and planning treatment. It is fair to state that the amount of time spent diagnosing and planning treatment may be affected by the dynamics of the practice (patient flow, volume of patients, # of operatories where the dentist is treating patients) and the philosophy of the dentist. Is there a standard method used by most dentists when it comes to diagnosing and treatment planning? The answer to this question may be related to our training in dental school. The curriculum in all accredited dental schools teaches students to diagnose and treat biologic and structural elements to ideal oral health. This includes soft tissue exams, periodontal disease, and dental caries. These examples are the foundation for the biological components of oral health. Structural elements can include broken and/or fractured teeth, as well as worn dentitions. Regardless of the duration of any dental program, the experience provides the student with enough knowledge and skill to take and pass the respective dental board exams. Upon graduating, most dentists all over the world begin their careers diagnosing/treating biological and structural

© Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_8

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issues, using the same methods learned in school. Even today as you read this book, many well-experienced dental practitioners (possibly including you) are still treating their patients in this same manner. This method of practice can be described as “tooth-by-tooth” dentistry or as Dr. Peter Dawson sometimes uses the term “a tooth plumber.” A “tooth-by-tooth” dentist is one that only looks at teeth (along with periodontal conditions of the same teeth) and nothing else. The teeth become the primary focus of all dental treatment. This is important to the overall oral health of the mouth and is not being discredited by any means. However, the importance of restoring teeth is a small piece of the larger puzzle and should not be the only method of solving dental/occlusal problems. Perhaps a “tooth-by-tooth” dentist should consider rethinking the relationship of how teeth play an important and integral role in function. For simplistic purposes the teeth are connected to their respected jaw bones. Since the mandibular bone is the only one that moves (rotation, translation, and excursive movements), its relationship to the maxilla is found in the glenoid fossa. Here the mandibular condyle rests and can rotate as well as translate within the glenoid fossa (via the articulating eminence). This relationship is enhanced when we introduce muscles, specifically the muscles of mastication. As muscles contract, function begins (chewing, speaking, swallowing, etc.). The connection between this function and where the teeth are positioned is the key element that differentiates a “tooth-by-tooth” dentist from a “complete” dentist. Figure 8.1 illustrates a comparison between both types of dentists with respect to the scope of understanding. Understanding this process does require further education outside dental school, and only when you understand how the masticatory system works can you change the way you approach the diagnosing and treatment planning process. It is this

Fig. 8.1  Contrast of the visual awareness between two approaches to patient care. Tooth-by-tooth dentistry (left—periodontium and dental caries), and complete comprehensive dentistry (right— TMJ, muscles, teeth, and function)

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reasoning that changes the normal approach of “tooth-by-tooth” dentistry to truly being a “comprehensive complete dentist.” Dr. Peter Dawson uses another term to describe this type of dentist, that is, a “physician of the masticatory system.” If we look at this term of being a “physician” rather than a “dentist” of the masticatory system, then it infers that you begin to think more like a medical doctor when examining your patients. After all, the head and neck is an area that dentists are very familiar with, but we must begin to behave and think more like a physician. For example, let us think about how a physician treats a patient for a yearly examination (or a specific problem). Here are the steps that you would expect. (a) History and vitals are taken. (b) Complete examination. (c) Labs and/or imaging ordered. (d) Results are analyzed. (e) Diagnosis reached. (f) Consultation and/or recommended treatment explained (if needed). (g) Treatment executed (if needed). The above seven steps can be considered the standard of care in medicine, and this can be the same standard of care in dentistry. The limiting factor in what separates the “tooth-by-tooth” dentist from a “comprehensive complete” dentist is the complete examination. A “tooth-by-tooth” dentist will primarily focus on examining bacteria and structural problems associated with teeth, and ultimately diagnose and treat those two elements. Treatment will consist of periodontal and restorative care in nature. A common example seen is when a patient presents with fractured cusp on a molar tooth. Figure 8.2 illustrates an example of such a patient who presents with multiple areas of concern. In this case, the patient has three areas of structural damage, vertical fracture of the last left molar, a cusp fracture of a restoration on the lower right molar, and mandibular anterior tooth wear/damage. Fig. 8.2  Patient example illustrating many areas of breakdown in the dentition. Dentists can approach treatment with this patient either tooth by tooth or comprehensively

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A “tooth-by-­tooth” dentist may view this patient and only treat to resolve only the fractured teeth by extracting the vertically fractured tooth and restoring the fractured crown with a new permanent restoration (full coverage crown). There is nothing ethically or morally wrong with this approach; however, if the cause of the original fracture was due to poor occlusion or function (most likely the cause in the majority of similar situations), then it is reasonable to state that in the future, the new restoration may also fracture in the same manner. When this occurs, the patient may view the dentist as responsible for correcting the original problem and expect them to resolve the matter, at potentially no additional charges. As a result, the dentist now has taken ownership of this problem since they are the ones who recommended the treatment in the first place. On the other hand, the “comprehensive complete” or “physician of the masticatory system” dentist would take a different approach to the same patient. Here, the “comprehensive complete” dentist will inform the patient that based on the initial assessment, the cause of this fracture may be due to a poor bite and/or function. This same dentist will provide options of restoring it permanently (much like the “tooth-by-tooth dentist”), or recommending treatment that will eliminate pain or temporarily resolve the problem (which is what the “comprehensive complete” dentist would prefer) for now with the understanding and recommendation that the patient return for a comprehensive examination to rule out any occlusal or functional source (or cause) of the problem. This approach gives the patient an opportunity to take ownership of the problem and make an informed decision. Regardless of the decision made, the patient understands the implications and consequences up front, and has the choice of restoring a damaged tooth much like a “tooth-by-tooth” dentist would or repair the issue at hand and have the “comprehensive” dentist examine the occlusion/function and recommend solutions that are predictable and long lasting. I think any patient given these two choices would rather have solutions solved rather than putting “band aid” approach. Thinking like a “comprehensive complete” dentist takes time but effectively gives patients options on how they want to solve their dental problems but more importantly eliminate the “blame” game often associated with the “tooth-by-tooth” approach. It is a common practice for a new patient entering an office not to see the dentist immediately. Usually, the new patient sees a dental hygienist and undergoes a series of radiographs, periodontal evaluation/charting, and respective hygiene visit. The dentist then sees the patient for enough time to examine only the bacterial and structural issues of the teeth. This is very typical of a “tooth-by-tooth” type of dental practice. However, a new patient entering the “physician of the masticatory system” office will first undergo a comprehensive examination by the dentist. Based on the outcome of the examination, appropriate radiographs are prescribed and taken. Based on the assessment of both structural and functional diagnosis, further diagnostic records (impressions, facebow, centric bite record, digital photography) may be indicated to further analyze the patient’s deteriorated dentition caused by poor or compromised function. Diagnosing and solving these problems will provide predictable restorative outcomes. The process of the complete examination is outlined in Chap. 4.

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In Chap. 4, the 12 steps of the complete examination are broken down to provide both structural and functional diagnosis. Steps 3–6 are used to formulate a functional diagnosis, while steps 7–10 are used to formulate the structural diagnosis. Figure 8.3 illustrates the breakdown of both structural and functional elements of the complete examination. The last two steps (11 and 12) represent the diagnostic occlusal analysis. Diagnosing and treatment planning are much like a puzzle, putting the pieces of the examination together to formulate a diagnosis and eventual predictable treatment plan. In order to explain this process, we will refer to Fig. 8.4

Fig. 8.3  Flowchart outlining the comprehensive examination process (steps 3–10)

Fig. 8.4  Flowchart outlining from the comprehensive examination (steps 3–12) to treatment acceptance

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as this diagram represents a flowchart illustrating the breakdown of the complete exam, diagnosis, and eventual treatment acceptance. This level of care when executed correctly will provide the restorative dentist with valuable information needed to solve simple and/or complex dental problems predictably. When the examination is completed correctly as in the flowchart, the dentist will have a good understanding of whether the patient is stable or unstable with respect to both the functional and structural diagnosis. A “stable” patient has a masticatory system that supports normal diagnosis in both structure and function. That is, healthy stable temporomandibular joints and muscles of mastication exhibit no signs of tenderness or pain, and the dentition does not show any signs of structural breakdown along with a healthy periodontium. This is represented in Fig. 8.5. On the other hand, an “unstable” patient exhibits a masticatory system with diagnosis of instability in either structural or functional components. This is represented in Fig. 8.6. Here any combination of instability in either TMJ, muscles, or teeth will categorize the patient as unstable. To solve any instability in the masticatory system, further analysis is required using diagnostic records (perfect impression, digital photographs, centric Fig. 8.5 Masticatory system is stable when TMJ, muscles, and teeth are stable

Fig. 8.6 Masticatory system is unstable when either TMJ, muscles, or teeth are unstable

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relation bite records, and facebow transfer). We will discuss how to use the diagnostic records to create a treatment plan later in this chapter. Should a patient be considered unstable, then it is important for them to know and understand the implications of their conditions. Diagnostic records should only be taken on patients who are ready to solve masticatory system problems. There are instances when patients are not ready (for many reasons such as financial and/or emotional) to solve their occlusal problems and may refuse diagnostic records. As difficult as this may be for the dentist, we must accept their decision and do our best to keep our patients as stable as possible. This will require the dentist to treat the patient’s biological and structural conditions to the best ability and keeping them as healthy as possible. It is also important to note that any treatment rendered while the masticatory system is unstable may diminish the life of the treatment. Your patient needs to clearly understand this point and it must be documented in the patient’s records. The purpose of this discussion is to help you the dentist understand and take ownership of the respective treatment plan with respect to the patient’s masticatory system problems. It needs to be done in a way that allows the patient to take ownership of their dental problems and can only be successful when the dentist is clearly communicating the implications of treating vs. not treating those conditions. Remember, the patient makes the final decision based on the information delivered and how it affects their emotional well-being. To be clear, this is not “selling” or “coaxing” any patient into accepting treatment, but simply asking you the dentist to be the best advocate or advisor for your patient. When the complete examination (Fig. 8.5) is correctly executed, the dentist will have a complete understanding of the patient’s masticatory system. We will now begin to discuss in more detail both functional and structural diagnosis.

8.1

Functional Diagnosis

The functional diagnosis begins within the first six steps in the complete examination process. Of these, steps three (3) to six (6) provide the clinical information related to function. This consists of examining three parts: the temporomandibular joints, muscles of mastication, and occlusion/centric relation. It is not unusual to find instability in at least one of these areas as they are all interconnected to provide function. The TMJ examination is the first area to be examined. The stability of this joint is critical in solving many occlusal problems. A stable TMJ is essential for a stable occlusion, and this becomes more important if treatment is needed to create a stable occlusion. For example, after completion of restorative treatment your patient begins to experience TMJ symptoms such as clicking and/or soreness. It would be fair to state that prior to restorative correction, the patient’s temporomandibular joints were not thoroughly examined as a potential existing joint condition was present and made worse from the restorative correction. That is the reason why the complete examination begins with examining the temporomandibular joints. Palpation, Doppler auscultation (ultrasound), and joint loading are methods of determining the stability of the temporomandibular joint (see Chap. 4, Figs. 7 and 8).

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Palpating the temporomandibular joint is the method to determine if there is any tenderness as well as to note any clicking or popping during opening and/or closing. Palpating the joints provides information (of the articulating disc) only on the lateral pole of the condylar head. A better more accurate method of evaluating the temporomandibular joints is to use Doppler auscultation. This instrument uses ultrasound to listen to the relationship of the articulating disc to the condylar head during all functioning movements (open/closing, lateral excursive, and protrusive movements), specifically, the relationship of the articulating disc on both the medial and lateral poles of the condylar head. A healthy, well-lubricated temporomandibular joint will exhibit minimal or no noise during normal functioning movements. However, if noises such as “click,” “pop,” or “crepitus” (grave sound) are heard, then the advantage of the auscultation device will help you determine where the sound originates from, either the medial or the lateral side of the condylar head. During rotation (up to approximately 20–25 mm), if you hear a click, pop, or crepitus, then it may indicate the location of the noise originating from the medial pole of the condylar head. This could indicate that the disc on the medial side of the condyle is either loose or anteriorly displaced and recaptures during rotation movements. In these circumstances, if you suspect a medial pole displacement then it is recommended to have an MRI prescribed for your patient to confirm your suspicion. However, sounds heard during early to complete translation (mandibular condyle moving down the articulating eminence) indicate that the articulating disc on the lateral side of the condyle is anteriorly displaced and may be recapturing during the translation. How does the articulating disc get displaced within the temporomandibular joint? To answer this question, let us first understand how occlusion affects the articulating disc. During full closure the condyles are seated and braced inside the glenoid fossa. Most of the bracing occurs on the medial side of the fossa which leaves the lateral side more venerable to changes. Discrepancies in occlusion between centric relation (lateral pterygoid muscle releases) and maximum intercuspation can occur from dental treatment, trauma, or parafunction. This discrepancy creates a conflict or disharmony between the lateral pterygoid (both superior and inferior bellies) and elevator muscles (temporalis and masseter). The combined contraction of both muscle groups to position the mandible in the maximum intercuspation position leads to stress. Over time, due to the continued forward position of the condyle, the lateral side of the articulating disc begins to loosen off the lateral pole of the condyle while the articulating disc on the medial side of the condyle is still braced. As a result, most temporomandibular joints start clicking at the lateral side first and as the condition worsens over time, the medial side of the articulating disc begins to change in the same manner. The important key point to note is that if you suspect a medial pole issue with the articulating disc, then it is prudent for you to request an MRI of the TMJ to confirm your suspicion. This needs to be confirmed by a medical radiologist. Table 8.1 illustrates the possibilities of results using the Doppler auscultation method, along with the last method of testing the TMJ, joint loading. Joint loading is the last method used to determine the stability of joint. A technique called “bimanual manipulation” allows the clinician to incrementally load both joints at the same time. When both joints are loaded, they are braced against the medial sides of the articulating eminence. If both joints can handle maximum loading without the patient indicating any tension (muscle tightness) or tenderness

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Table 8.1  Functional diagnosis—Doppler auscultation + joint loading

Right or left TMJ

Rotation (medial pole) − − − + +

Translation (lateral pole) − + + + +

Joint loading − − + − +

TMJ stable/ unstable Stable Stablea Unstableb Unstablec Unstablec

Only if joint can be fully loaded Consider deprogrammer and/or occlusal splint therapy c Recommend MRI to confirm articular disc

a

b

(discomfort—internal joint damage), then we have confirmed the stability of the joint as well as the final joint position as centric relation. However, if the patient indicates that the joints exhibit tenderness on loading, then we must investigate and confirm the condition of the joint. Treating the joint first until stability is reestablished is recommended before any other restorative treatment. We will discuss this in further detail during the treatment planning segment of this chapter. For the purposes of this chapter, a positive joint test (+) can be defined as either temporomandibular joint exhibiting tenderness to full loading, joint pain on palpation, or clicking and/or popping of the articulating disc at the medial pole of the condylar head. Subsequently, we will define a negative joint test (−) as the temporomandibular joint exhibiting no tenderness on full loading, no joint pain on palpation, and no clicking and/or popping of the articulating disc at the medial pole of the condylar head. In addition, we must also clarify that if a patient has a click and/or popping of the articulating disc on the lateral pole of the condylar head, and as long as the medial pole is stable, then this would constitute a joint that is modified internally, but stable because it can accept loading. Treatment (restorative) can be rendered on these patients; however, the joint needs to be monitored by the dentist periodically to maintain and prevent the condition from worsening. The second element in functional diagnosis is the muscles of mastication. Within these muscles are groups that provide specific jaw movements. A review of these muscles include both masseter and temporalis-to close the mandible, while the digastric muscle opens the mandible. Both lateral and medial pterygoid muscles are responsible for positioning the mandibular condyle in the glenoid fossa during opening and closing. It is important to note that when there exists a discrepancy of the dentition from centric relation (first point of contact when both joints are loaded firmly) to maximum intercuspation, the mandible stays in an anterior position (not by much) with the help of both lateral and medial pterygoid muscles. When you add function (chewing, swallowing, yawning, speech, etc.), these same muscles are working against others and are often overworked. During palpation of all the muscles of mastication, we expect some positive (tenderness) feedback (mild, moderate, or severe). If the patient’s muscles of mastication are working with an ideal occlusion, then we expect all muscles of mastication to exhibit no tenderness at all. Thus, a positive (+) test is when a patient responds to tenderness to any of the muscle of mastication. It is important to note that most of your patients will exhibit two causes

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of muscle tenderness: those who have chronic parafunction and occlusal-muscle malocclusion. The former involves a clenching and/or grinding pattern and we expect to see the elevator muscles (see Fig.  8.7) to exhibit tenderness (mild to severe—depending on the severity) to palpation. The latter involves a discrepancy between centric relation and maximum intercuspation causing the positioner muscles to keep the mandible in a more forward position due to occlusal interferences in centric relation. Here we expect the positioner muscles (see Fig. 8.8) to be tender.

Fig. 8.7  Muscles of mastication—positive response to elevator muscles

Fig. 8.8  Muscles of mastication—positive response to positioner muscles

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The third and last element of functional diagnosis is occlusion. The vast majority of dentist’s scope and knowledge of occlusion vary greatly. However, this majority has one common understanding of occlusion, that is, for patients to simply bring their teeth together in contact. Occlusion is the last item to be checked and verified (using articulating ribbon or paper) for many dental restorative procedures. Over the years, I have had the opportunity to speak with many dentists from around the world, and the majority do understand the basics of occlusion—that is, to simply bring patient’s teeth into contact. However, they fail to understand the relevance it has on the outcomes of their patient’s treatment. One explanation given is that the dental school curriculum of occlusion was too complex, and the lasting impression is that prosthodontists are the only specialty in dentistry that truly understand and appreciate occlusion. The irony here is that the vast majority of university dental school professors teaching occlusion are prosthodontists. Are they making it too complex for dental school students? Or why so many dentists (globally) think and feel that occlusion is a subject of unpopularity and often underestimated? I don’t know all the answers to these questions, but what I do know is that if we can make the concept of occlusion simple enough, then perhaps we may change their view and make occlusion more relevant in their respective practices. The author feels that occlusion has taken a back seat to other more popular topics such as digital technology or dental implants. Regardless of how a dentist chooses to use technology in their respective practices, occlusion should never be downplayed as the long-term success of treatment is dependent on a stable occlusion. Occlusion for many decades is still by far one of the most controversial topics in dentistry. The reasons for this can be related to different concepts of occlusion such as neuromuscular and joint-based occlusion. While the former measures muscle activity to establish a comfortable resting position of occlusion, the latter uses a centric relation joint position to establish occlusion. The neuromuscular concept measures electrical activity of both masseter and temporalis when establishing occlusion. These muscles are only involved in closing the mandible. However, there are other muscles that play an important role in function. That is the medial and lateral pterygoid muscles. It is impossible to attach electrodes to these muscles because they are mostly hidden and access may be only achieved intraorally. Placing electrodes intraorally is very difficult if not an impossible task. Not taking these muscles into consideration may not produce a comfortable result for the patient. On the other hand, a joint-based approach to occlusion takes into consideration all muscles including both medial and lateral pterygoids. We will focus our discussion using a joint-based approach to occlusion. Occlusion starts with an understanding of two important concepts, a stable repeatable joint position (centric relation) and the functional significance of anterior teeth. When the joints are loaded (full contraction of depressor muscles—temporalis, masseter, and medial pterygoid), seated in centric relation, along with having both mandibular and maxillary anterior teeth in contact (creating a stable stop), this becomes the foundation of occlusion. These two concepts are evident in our DNA.  We are born with a temporomandibular joint and no teeth. During early development (after 6 months), the first set of teeth to erupt are the mandibular central incisors, eventually followed by the maxillary central incisors. Figure  8.9

164

8  Diagnosis and Treatment Planning DECIDUOUS DENTITION 5 months in utero

MIXED DENTITION 2 years (± 6 mos)

11 years (± 9 mos)

7 years (± 9 mos)

7 months in utero PRENATAL

PERMANENT DENTITION

12 years (± 6 mos)

3 years (± 6 mos) Birth

6 mos (± 2 mos)

8 years (± 9 mos)

4 years (± 9 mos)

9 mos (± 2mos)

15 years (± 6 mos)

9 years (± 9 mos)

5 years (± 9 mos)

21 years

1 year (± 3 mos)

6 years (± 9 mos)

18 mos (± 3 mos) Infancy

Early childhood (Pre-school age)

35 years

10 years (± 9 mos) Late childhood (school age)

Adolescence and adulthood

Fig. 8.9  Eruption sequence of both primary and secondary human anterior dentition

illustrates the eruption sequences of both child and adult dentitions. These teeth continue to erupt with the support of the soft tissues (lips and tongue) until contact is established. At that stage, fully contracted masseter and temporalis muscles seat the joints while that anterior teeth maintain contact. This anterior stop (or contact) now establishes the vertical dimension of occlusion (VDO). Figure 8.10 illustrates the relationship of a repeatable seated joint position (centric relation), anterior teeth (central and lateral incisors) contact, and a fully contracted masseter muscle. This relationship establishes the vertical dimension of occlusion and as growth continues, more teeth begin to erupt and find their place to occlude with each other at the same vertical dimension of occlusion. Throughout the life of a patient, dental occlusion can change from years of dental treatment, orthodontic treatment, trauma, and parafunction. Regardless of the cause, changes in occlusion require the masticatory system to adapt. This may include slight changes in joint position—that is, away from centric relation, or muscle adaptation—muscles of mastication shifting the mandible to compensate for interferences. Over time this adaptation can sometimes lead to signs of occlusal breakdown. Recognizing these signs of breakdown is critical to understanding occlusal problems. Cracks, wear, abfractions, and loose teeth are some of the common signs of occlusal problems as these signs indicate an existing stress within the masticatory system. You will be surprised to see that most of your existing patients already have some of these signs of occlusal instability. The problem with restoring teeth and

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Fig. 8.10  Connection of the anterior teeth eruption and vertical dimension of occlusion

Fig. 8.11  Signs of occlusal instability: Patient example illustrating abfraction, recession, and rotation of teeth

ignoring the problem of occlusal instability usually results in failure. Many dentists run into this problem, as they restore teeth without understanding the existing occlusal problems. Figure  8.11 illustrates a patient with many signs of occlusal stress including abfractions, gingival recession, and rotated teeth. Recognition of occlusal problems starts at the comprehensive examination and will reveal if your patient has any of these signs. In Chap. 4, evaluating the occlusion is step five (5) that involves the following: 1 . Occlusal dental classification (class I, II, or III). 2. Measure overbite and overjet.

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3. Document occlusal contacts along with both working and balancing (non-­ working) interferences using articulating ribbon. 4. Visually examine teeth for signs of breakdown (cracks, wear, etc.). This becomes important to know when it comes time to document. Of these four items, the last two are most important as this will indicate instability in the occlusion. Working and balancing interferences in posterior teeth create increased muscle activity which places more mechanical stress on teeth. Remember that mandibular movement (closing) is categorized as a class III lever mechanism and the vast majority of “load” resides in the posterior area (see Fig. 8.12). If not corrected, over time surfaces of buccal areas may appear dull or flat and/or abfractions will be present. When examining your patients, if there are signs such as abfractions, then suspect working/balancing interferences as a possible cause. Understanding or recognizing occlusion problems does not become important unless the restorative dentist knows what an ideal occlusion should look like. An ideal occlusion will have contacts of equal intensity with both anterior and posterior teeth in centric relation (see Fig. 8.13), along with no working or balancing interferences. Removing or eliminating posterior interferences can be best accomplished by having canine disclusion (cuspid guidance, or cuspid protection); see Fig. 8.14. The thickness of the maxillary canine tooth, length of the root, and incline of the lingual surface make this tooth ideal for this role. However, since we are discussing joint-based occlusion, we would also include the joints seated in centric relation. One method of verifying centric relation is using bimanual manipulation. The technique (see Chap. 4 for details) of bimanual manipulation involves increments of loading the joints until firm loading is achieved. As long as the patient is comfortable on firm loading, we have confirmed

Fig. 8.12  Mandible movement as a class III lever system

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Fig. 8.13  Ideal occlusal scheme: even contacts on all teeth in centric relation. The following contact points represent the following: “green”— functioning cusps of maxillary teeth; “black”— functioning cusps of mandibular teeth; “blue”—mandibular anterior contacts

centric relation. As the patient begins to close, pay attention and observe if there is a deflective or premature contact in centric relation. Asking the patient to identify the first point of contact is the best method as it also involves engaging the patient and allowing them to feel that they are contributing to the discovery of this finding. Once the patient acknowledges the premature contact, they are instructed to squeeze their teeth together till all the other teeth are in contact (maximum intercuspation). Movement of the mandible (always anterior) shows us an occlusal discrepancy between centric relation (first point contact) and maximum intercuspation. To make this experience even more effective, give the patient a hand mirror and let them see the difference between their respective first point of contact and the mandible sliding into maximum intercuspation. Ideally, a perfected occlusion will have complete contact on all teeth in centric relation. One of the goals in “complete dentistry” treatment planning is to eliminate the occlusal discrepancy between centric relation and maximum intercuspation. When restoring anterior teeth, not eliminating this discrepancy (between centric relation and maximum intercuspation) becomes risky as the anterior slide may cause interference with the new restorations. This is especially true when you are attempting to restore anterior teeth that have moderate wear and involve changing the incisal edge

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Fig. 8.14  Ideal occlusal scheme: even contact on all teeth in centric relation with anterior guidance— complete disclusion of all posterior teeth

position and/or length. Please refer back to Chap. 3 for more information. Diagnosing occlusion starts with an understanding of how teeth interact with each other during excursive movements, as well as any discrepancies between centric relation occlusion and maximum intercuspation.

8.2

Structural Diagnosis

Structural diagnosis takes place during steps seven (7) through ten (10) in the 12 steps of the comprehensive examination. Completing these steps will provide the dentist with a complete understanding of the structural integrity of the dentition. Attention must be given to documenting the structural integrity (breakdown) of all the teeth related to decay, periodontal health, and function that are all important elements to document. Some signs of breakdown include the following: 1. Moderate tooth wear—many patients will exhibit moderate tooth wear in the anterior teeth, but little or no wear in the posterior teeth (see Fig. 8.15). 2. Cracks (vertical and horizontal)—these can be subtle in nature, or very obvious. Using the intraoral camera, you can pick up more detailed information on

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169

Fig. 8.15  Patient examples of moderate tooth wear: Structural diagnosis

Fig. 8.16  Patient examples of cracks (vertical and/or horizontal): Structural diagnosis

cracked teeth. Anterior teeth that are worn down may exhibit cracks (see Fig. 8.16). 3. Abfractions—these signs are very common and are sometimes more prevalent with bicuspids (see Fig. 8.17). 4. Fractured teeth—teeth can fracture due to caries, defective restorations, and occlusal forces. Excessive forces on working and balancing sides can cause tooth fractures (see Fig. 8.18). It is important to understand that many of the signs of breakdown are related to functional problems. A “tooth-by-tooth” dentist will focus all efforts on solving structural problems without understanding the patient’s function. Over time, these same restorations may fail due to an unrecognized functional problem(s).

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Fig. 8.17  Patient examples of abfraction lesions: Structural diagnosis

Fig. 8.18  Patient examples of fractured teeth: Structural diagnosis

8.3

Diagnostic Occlusal Analysis

At the end of the complete examination the dentist should have a good understanding of the patient’s oral health from a biological, structural, and functional perspective. Should both structural and functional diagnosis be stable, then the treatment planning process proceeds as normal—that is, treat the patient’s biological and structural needs in the patient’s habitual joint position. On the other hand, should either the structural or the functional diagnosis result as “unstable,” then the next step is to proceed further with diagnostic occlusal treatment assessment (DOTA). The requirements for the DOTA are discussed in Chap. 5 and consist of the following:

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171

1 . Accurate impressions of both arches (Chap. 5, Fig. 32) 2. Facebow (Chap. 5, Fig. 21) 3. Centric relation bite record (Chap. 5, Fig. 27) 4. Semi adjustable articulator (Chap. 5, Fig. 13) 5. Digital photography (Chap. 5, Fig. 44) These records are used to reproduce the occlusion when both temporomandibular joints are seated in centric relation, duplicating the first point of contact. To confirm that the models are mounted correctly, the first point of contact noted in the patient’s chart must be the same on the mounted models. There are many instances when discrepancies of the first point of contact exist between what is documented in the patient’s chart and what is found on the mounted models. This can pose some frustration for the dentist as this would indicate that the records were not taken accurately, which in turn may create a situation of less predictability. There are reasons for these discrepancies, and they are discussed in further detail in Chap. 5. An interesting point to note is that mounting models on any articulator is not a common practice among the vast majority of dentists. I was among those practitioners, and to be honest felt at the time it was too much work and was not necessary. In addition, laboratories did not require cases to be mounted as everything was hand articulated. Since then, I have asked many dentists this question: “When do you decide to mount models on an articulator?” Some of the more popular responses from those dentists include: (a) Full-mouth rehabilitation (b) Anterior aesthetic treatment (c) Three-unit fixed partial denture (bridge) (d) Dental implants (e) Dentures Based on some of the responses, it is clear that treatment chosen by the restorative dentist is dictating when to mount the patient’s models on an articulator. In other words, treatment plan first, and then decide whether the patient’s case requires mounting using an articulator. This is very typical of the “tooth-by-tooth” approach, and based on the various reasons becomes a very subjective decision. There is no structured thought process on why models should be mounted, and the reasons are inconsistent. However, the mindset of the “complete” dentist is to assess the stability (structural and functional) first, and then based on that assessment (whether the patient is stable or unstable) recommend diagnostic records. Using the patient’s mounted models in centric relation, an occlusal analysis can be completed, and finally a comprehensive treatment plan that is based on establishing occlusal stability and harmony. This approach transforms the thinking of the “tooth-by-tooth” dentist to a “physician of the masticatory system” dentist. This transformation requires discipline, commitment, and improved methods of communication between the dentist and patient. Most patients are used to having a treatment plan provided at the time of the initial examination. This process eliminates this expectation because a well-trained dentist and team create a clear communication on the

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expectation of why this method is best for the patient. As part of this communication, the dentist responsibility is to make sure that the patient is aware and understands that there are both structural and functional problems. Solving these problems with conservative treatment requires the diagnostic occlusal treatment analysis (DOTA) to be completed on all patients that exhibit structural and/or functional instability. On the other hand, there will be patients who are not ready to proceed with the DOTA either due to financial reasons or simply because solving those problems is not a priority at that time. Be patient with them, treat biological and structural issues as needed—but always make sure that you are clear in your communication on the implications of restoring teeth in a compromised or unstable masticatory system. To clarify further, tables below summarize both functional and structural diagnosis with respect to the complete examination. This will provide you with clarification on your assessment and its relevance to determine whether the masticatory system is stable or unstable. Remember, your patient’s masticatory system can be considered “unstable” when your patient exhibits instability in either the structural and/or functional diagnosis. Table 8.2 outlines the various combinations of an compromised “functional” diagnosis, whereas Table 8.3 is the opposite. Table 8.4 outlines the various combinations of the “structural” diagnosis. The DOTA process is broken up into two parts, the occlusal analysis (Table 8.5) and the treatment assessment (Table 8.6). The occlusal analysis is structured to give you an understanding of the present occlusal relationship. Having this information will give you an idea of how far or how close is an ideal occlusion. The occlusal analysis first begins by verifying that centric relation recorded in the mouth is the Table 8.2 Functional diagnosis-unstable

TMJ + + + + − − −

Muscles of mastication + + − − + + −

Occlusion + − − + − + +

Table 8.3 Functional diagnosis-stable

TMJ − +a

Muscles of mastication − −

Occlusion − −

Lateral pole click, load test negative

a

Table 8.4 Structural diagnosis

Teeth conditions + + − −

Periodontal health + − + −

Stable/unstable Unstable Unstable Unstable Stable

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Table 8.5  Occlusal analysis Assessment 1 Verify first point of contact in CR on models 2 Pin setting between CR and MI 3 Mark lower and upper incisal edges 4 R-working//L-balancing interferences 5 L-working//R-balancing interferences 6 Protrusive interferences 7 Evaluate maxillary and mandibular arch form anterior/ posterior 8 Evaluate maxillary and mandibular anterior crowding a

Analysis Teeth #: Discrepancy (yes/no) __ mm Thin/normal/wide Yes/no  R—W teeth #:       L—B teeth #: Yes/no  L—W teeth #:       R—B teeth #: Yes/no  Teeth #: Narrow/normal/widea Slight/moderate/severea or none

Consider orthodontics as an option

Table 8.6  Treatment assessment Assessment 1 Correct mandibular arch form 2

Correct mandibular incisal edgesd

Photography reference

(Yes/no)

Recontour Treatment and/or waxing recommendationa,b,c

Mand. occlusal Mand. occlusal Mand. anterior Mand. retracted open (anterior, left & right)

3 Correct maxillary arch form

Max. occlusal Smile view

4 Correct maxillary incisal edgese (Length = width X 1.25)

Max. occlusal Max. anterior smile, repose Tip down Lateral smile profile

5 Equilibration (CR = MI) Reductive Additive 6 Equilibration (excursive) Reductive Additive

Correction of facial and/or incisal surface = veneer restoration (composite or all porcelain) Correction of facial/incisal/occlusal/ buccal and lingual surfaces = crown restoration (PFM, gold, or all porcelain) c Correction of cusp (one or two) = onlay restoration (composite, gold, or all porcelain) d Teeth #3.3–#4.3, #22–#27 e Teeth #1.3–#2.3, #6–#11 a

b

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same on the models. While the articulator is locked into centric relation, place articulating paper, and mark the first point of contact. Verify it from the patient’s chart. Here, Fig. 8.19 illustrates the premature contact in centric relation marked with blue ribbon on the maxillary and mandibular left second molar. The second step is to understand the discrepancy between centric relation (CR) and maximum intercuspation (MI). This is accomplished by releasing the pin lock (that locks the articulator in centric relation), manually squeezing the models into maximum intercuspation, and setting the incisal pin onto the incisal table. The articulator then locked back into centric relation. If there is a discrepancy between CR and MI, the pin should be off the incisal table. This gap represents the distance between CR and MI, vertically. Figure 8.20 illustrates the left side of the models in both centric relation and maximum intercuspation. In this example, it is clear that there is a visual discrepancy between centric relation and maximum intercuspation. The distance is measured off the difference in the pin setting between the CR and MI. The third step is to mark (with pencil) the maxillary and mandibular incisal edges on both the facial and lingual sides. This reference will leave you with a visual on the thickness of the incisal edge. Ideal incisal edges are usually between 1.0 and 1.5 mm in width. Should you have incisal edges that are worn, they will most likely be greater than the ideal width. Modification of the maxillary and mandibular incisal edges will result in appropriate treatment that will be discussed in the next section. Again, this is a visual check so that you have an idea of what changes need to take place. Figure 8.21 illustrates the incisal edges of both maxillary and mandibular casts. Here modifications will need to be made to create ideal incisal edge. These will be illustrated in our next section. The fourth and fifth steps in the occlusal analysis represent an

Fig. 8.19  Occlusal analysis: Step 1—verify first point of contact in centric relation

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175

Fig. 8.20  Occlusal analysis: Step 2—Determine difference between centric relation (CR) and maximum intercuspation (MI) using the pin setting

Fig. 8.21  Occlusal analysis: Step 3—Identify incisal edges of both maxillary/mandibular anterior teeth

understanding of any existing working and/or balancing interreference. Using articulating paper (full sheet, different color) release the CR lock, and move the upper chamber to create right working/left balancing as well as left working/right balancing. Any interferences will leave a mark on the corresponding posterior teeth. Ideally, with the aid of cuspid guidance, there should be no posterior interferences at all. The same models are used in Fig. 8.22 to illustrate both working and balancing posterior interferences. Notice that there is no canine guidance associated with

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Fig. 8.22  Occlusal analysis: Steps 4 and 5—Identify working/balancing interferences

either left or right working sides. The dentist can look at this result and determine how much occlusal equilibration may be needed to create an ideal occlusion. This process mentioned above can also be applied to step 6 in the occlusal analysis. Here, documentation of protrusive interferences is given. Using the same articulating paper, slide the upper chamber backwards mimicking protrusive movement, and note any posterior interference. Again, we would like to see the anterior teeth providing guidance to separate the posterior teeth. Please note when checking protrusive interferences, pay attention to see if the lower canine teeth interfere with the maxillary lateral incisors. If that is the case, then consider shortening the maxillary lateral incisor. The models in Fig. 8.23 illustrate protrusive interferences on the left molars. The final two steps, steps 7 and 8, are related to the amount of space between the right and left sides as well as the space between the teeth. Both of these parts are related to each other as sometimes a narrow arch may have anterior teeth that are crowded. Correcting the arch form may benefit by helping correct anterior crowding as well as providing more space for the tongue to rest and subsequently improve the airway. Orthodontic treatment may be considered as a means of correcting arch form and/or crowding. Remember, upon completion of orthodontic treatment, the occlusion and tooth position will change. This will require updated diagnostic records along with a new DOTA. However, there are patients who will refuse orthodontic treatment, and thus working with a narrow or crowded arch form may pose challenges to the restorative dentist. In our example, Fig. 8.24 illustrates that the arch form and crowding are a nonissue. The second part of the DOTA is the treatment assessment. Here we begin working on the models to create the ideal treatment plan that also creates an ideal occlusion. With information gathered and completed in Table  8.5, the treatment assessment

8.3 Diagnostic Occlusal Analysis

177

Fig. 8.23  Occlusal analysis: Step 6—Identify protrusive interferences

Fig. 8.24  Occlusal analysis: Step 7—Identify maxillary/mandibular arch forms

process can begin by utilizing the mounted models on the articulator along with the digital photographs. This protocol is structured so that our end result meets the requirements of stable occlusion. We will discuss each section (1–6) in Table 8.6 with more detail to explain how the treatment planning process is formulated. Steps 1 and 2 are only related to the mandibular arch, while steps 3 and 4 are related to the maxillary arch. The final steps 5 and 6 involve equilibration so that all teeth occlude evenly as well as anterior teeth providing the posterior teeth disclusion during excursive movements. It is important to define what changes take place during

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Fig. 8.25  Occlusal analysis: Step 8—Identify maxillary/mandibular anterior crowding

these steps and then convert or translate these changes to actual treatment procedures. This translation is solely based on what modifications are completed to the mounted models. Below Table  8.6, there is a reference guide of modifications to teeth that translates to a procedure. Changes or corrections that involve the facial and/or incisal edge of anterior teeth equate to a veneer restoration (fabricated from composite or porcelain). Corrections made on any multiple combination of facial, lingual, incisal, buccal, or occlusal surfaces equate to a full coverage restoration (PFM, gold, or all-porcelain crown). Here, existing crowns that are already defective or failing would require a new restoration with a new shape based on the DOTA. Finally, any corrections made to posterior buccal or lingual cusps (at least one or two) would equate to an onlay restoration (composite, gold, or all porcelain). In this case, existing restorations that are compromised due to defective margins and/ or caries may be modified to this type of restoration based on the DOTA (Fig. 8.25).

8.3.1 Steps 1 and 2 When reviewing the mandibular cast, along with the corresponding occlusal photo, examine the flow of the arch form starting on one side to the contralateral side. Ask yourself, “Do the anterior teeth follow a consistent arch form with the posterior teeth?” If the answer is “no,” then use the posterior buccal cusps as a reference and using the outlined incisal edges (step 3, occlusal analysis: Table 8.4), start to envision a more ideal arch form. Recontour the facial and lingual surfaces of the anterior teeth to create a more ideal arch form. Any deficiencies to create the ideal arch form can be filled in with wax. Our patient example is illustrated in Fig. 8.26—here the

8.3 Diagnostic Occlusal Analysis

179

Fig. 8.26  Treatment planning assessment: Step 1—correct mandibular arch form

arch form appears normal as the posterior buccal cusps and the anterior incisal edges follow an acceptable arch form. As a result, there is no modification needed in this example, and we can proceed to step 2. In this next step, evaluate the mandibular anterior teeth from canine to canine, and from the canine tooth to its distal neighbor (bicuspid). Ideally, the incisal edges of the mandibular teeth should be in the same incisal plane as the mandibular canines, and the canine teeth should be slightly higher than the first bicuspid. This transition from bicuspid to cuspid represents the anterior end point of the curve of Spee. Figure 8.27a illustrates our patient with a deficiency in the central and lateral incisal edges but has a good transition between the canine and bicuspid. In addition, this particular case illustrates that the canine teeth have a normal relationship with the neighboring bicuspid on both sides. The method used is to first examine the models and determine the relationship of canines to the corresponding first bicuspids. If you notice that the canine is deficient in this manner, select either the left or the right canine, and wax in the incisal edge while keeping the arch form intact. Follow this with the contralateral canine tooth and verify that both sides are similar in height. In the example in Fig.  8.27b the patient’s cuspids are in a more ideal position in relation to the neighboring bicuspids. In this case no modifications were needed to the canines, we can then focus on the lateral and central the incisal edges. Using the canine’s incisal edge as a reference, create the new incisal edge for the lateral incisors on both sides, followed by the central incisors. When this is completed, you should have an incisal plane that is even while still maintaining the ideal arch form. Figure 8.27b illustrates the deficiency in the mandibular incisal edges, and the wax-up to create an ideal incisal plane between both mandibular canines. Because we have corrected the incisal/ facial edge of teeth #32–#42 (#23–#26) the restoration of choice is veneer type, in composite or porcelain. Now that you have established the lower incisal plane, you are ready to proceed to the next steps in the treatment assessment.

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8  Diagnosis and Treatment Planning

a

b

Fig. 8.27 (a) Treatment planning assessment: Step 2—correct mandibular incisal edges. (b) Treatment planning assessment: Step 2—corrected mandibular incisal edges (Tx choice made either porcelain or composite)

8.3.2 Steps 3 and 4 Step 3 involves using the maxillary cast, and corresponding occlusal photo to examine the flow of the arch form using the same method as outlined in step 1 above; repeat this process as needed. Figure 8.28 illustrates our patient example of the maxillary arch form and it is noted that teeth #12 (#7) is rotated mesial, while #11 (#8) and #21 (#9) are not ideal in shape. We will recontour the stone conservatively and then wax into ideal contours. Remember, this is a conservative method and too much recontouring may lead to more time needed for wax-up.

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181

Fig. 8.28  Treatment planning assessment: Step 3—correct maxillary arch form

Step 4 addresses the maxillary incisal edges. The incisal edge position is more complex as compared to the corresponding mandibular teeth. Instead of starting with the canine teeth as in step 2, step 4 starts with locating the central incisal edge, and finishes with the canine incisal edge. Before beginning to analyze the incisal position, it is recommended to get an understanding of where the incisal edge will be located. The location of the central incisor edge is to provide aesthetics, phonetics, and function. This location is specific in two planes, vertical and horizontal. To locate the ideal incisal edge position, the vertical plane is referenced by using two photos: “E smile” and “repose,” while the horizontal plane uses the “tip-down” and “lateral smile profile” photos. Figure 8.29a demonstrates these four photographs along with images of the occlusal views and maxillary anterior teeth. Note that the gingival margins of both #11 (#8) and #21 (#9) are not symmetrical as this can be corrected with either gingivectomy or crown lengthening. In addition, Table 8.7 provides information on the boundaries of the maxillary incisal edge position to the four photos. To make sense of this, we start with the vertical reference. Using the “repose” photo, if we see 1–3 mm of incisal edge exposure, then we can safely conclude that the vertical position is adequate. However, as stated in Table  8.7, this exposure is age dependent. Increased age shows maxillary display and reveals more of the lower incisors. If a patient does not show any incisal edge at rest, it does not necessarily mean more incisal edge is needed. Figure 8.29b illustrates the rest position with minimal exposure of teeth #21 (#9) and no exposure of tooth #11 (#8). Confirmation of the incisal edge vertically is done by viewing the “e” smile photograph. Here we draw a line at the inferior part of the upper lip, and another at the superior part of the lower lip, and then we would like to see the incisal edge of the maxillary central incisor to fall within these two lines at approximately 50–70% of that distance. Figure  8.29b illustrates this with our patient showing that tooth #21 (#9) is vertically correct as

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it extends beyond the 50% mark. With this in mind we will keep the incisal edge position of #21 (#9) in the same vertical position. Using the same example of a patient not showing enough incisal edge at “repose,” the “E smile” photo will confirm whether the incisal edge needs to be lengthened, shortened, or left alone. On the other hand, if a patient shows too much incisal edge at “repose” and you are considering shortening it, again, use the “E smile” to confirm by checking if the maxillary incisal edge extends beyond the 70% mark. a

b

Fig. 8.29 (a) Treatment planning assessment: Step 4—assessment of photographs and gingival margins. (b) Treatment planning assessment: Step 4—repose and E smile: vertical assessment of maxillary incisal edge position. (c) Treatment planning assessment: Step 4—tip-down smile and lateral smile: horizontal assessment of maxillary incisal edge position. (d) Treatment planning assessment: Step 4—reshaping and waxing of ideal incisal edge position along with ideal length-­ to-­width proportions. (e) Treatment planning assessment: Step 4—completed wax-up to ideal golden proportion

8.3 Diagnostic Occlusal Analysis

c

d

e

Fig. 8.29 (continued)

183

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8  Diagnosis and Treatment Planning

Table 8.7  Incisal edge position and photography Photograph “E smile”

Plane Vertical

“Repose” “Tip down” “Lateral smile”

Vertical Horizontal Horizontal

Incisal edge reference 50–70% of the distance between upper and lower lip 1–3 mm exposure, age dependent Inside vermillion border of lower lip Inside vermillion border of lower lip

The horizontal incisal edge position of the maxillary incisor is confirmed by viewing the relationship of this edge to the inner vermillion border of the lower lip, also known as the “wet-dry line.” Using both “tip-down” and “lateral smile,” the incisal edge should be positioned at this wet-dry line. Figure 8.29c illustrates this horizontal incisal edge verification. Our patient exhibits normal horizontal incisal edge position in both photos. In this case we will not change the horizontal position of the maxillary anterior teeth. Using the four photos to understand the location of the maxillary incisal edge position, completely modify (recontour and/or wax) the incisal edge to the ideal position. Remeasure the new length and compare it to the original desired length. If the length of the incisal edge is increased by an amount less than the difference calculated between the ideal length, and the original length, then the additional amount needed to achieve the ideal length-to-width ratio, is to modify the gingival margin appropriately (gingival recontouring or crown lengthening). By choosing the best central incisor, measure the width using a digital caliper. Take this number and multiply it by a factor of 1.25 (multiple factor of the 80% rule: width of the central incisor is approximately 80% the length of the unworn tooth). In our patient example, Fig. 8.29d illustrates the measurement, but when placing the models on the golden proportion ruler, the existing width is too wide for the arch form. Restoratively speaking, based on the ideal golden proportion ruler, the ideal width of the central incisors should be 8.0 mm. The corresponding ideal length now needed is 10.0  mm (width of 8.0 mm  ×  1.25 ratio factor). The difference is the amount of tooth structure needed to achieve the ideal length to width. When both central incisors have been completed, recontour or wax the incisal edge of the canine teeth so that the incisal edges match those of the central incisors. Finally, create balance with the lateral incisors so that the incisal edges are slightly shorter than the neighboring central incisors (remember that the lateral incisors are shorter to avoid the mandibular canine teeth during protrusive movements). Figure 8.29e illustrates the completed wax-up with the new incisal edge position along with ideal length-to-width proportions. It is noted here that the wax-up now fits into a more desirable golden proportion.

8.3.3 Step 5 Once the mandibular and maxillary anterior teeth have been contoured and incisal edges are in place, the next step is to finalize the occlusion. Equilibration is a process of creating balanced occlusal forces by reshaping contours and inclines of all teeth. Equilibration can be reductive and/or additive in nature, and in most situations, equilibration begins as a reductive process. With the same incisal pin setting

8.3 Diagnostic Occlusal Analysis

185

(as outlined in the occlusal analysis, step 2—Table 8.5), mandibular and maxillary casts are placed back onto the articulator. The occlusal relationship with the articulator locked in centric relation now has two possibilities: 1 . The first point of contact is still the same—anterior teeth not in contact 2. The front teeth contact—posterior teeth not in contact The first possibility is most commonly seen and reductive equilibration is used to idealize the occlusion while in centric relation. The goal here is to continue to equilibrate until anterior teeth are in contact. The second possibility usually results in an additive equilibration where posterior teeth need to be modified with extra material to create an ideal holding contact. Here wax would be used to add height to maxillary and mandibular posterior cusps and fossa to complete the equilibration. A word of caution, before you proceed to decide to wax in contacts in the posterior teeth, reassess the length of both mandibular and maxillary incisal edges-if you feel they are too long, then consider altering them. Regardless, even contacts in centric relation are required before proceeding to step 6. This particular example is when there is a lot more complex restorative care. Figure 8.30 illustrates the photos of the equilibrated models in place.

8.3.4 Step 6 Equilibration continues in step 6, except now posterior interferences are removed (documented in the occlusal analysis, steps 4–6—Table 8.5) during excursive movements. Eliminate right and left working and balancing interferences by unlocking the centric pin on the articulator. Using articulating paper, start by gently

Fig. 8.30  Treatment planning assessment: Step 5—equilibration to ideal occlusal contacts so that centric relation is the same as maximum intercuspation

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Fig. 8.31  Treatment planning assessment: Step 6—equilibration to correct excursive movements resulting in no posterior working or balancing interferences

moving the upper chamber to the respective working side. Eliminate any inclines on posterior teeth that interfere during these movements. Repeat this process for the contralateral side. If the initial equilibration is done correctly (step 5), then it is common to see minimal working/balancing interferences. This almost self-­ correcting process occurs as anterior guidance is now more effective than first noted during the occlusal analysis (Table 8.4). Figure 8.31 illustrates the completed equilibrated models showing uniform contacts with excursive guidance with no posterior interferences. This serves as the template for the preparation design and the provisional restorations. Using the information gathered from the occlusal analysis (Table 8.5) and treatment assessment (Table 8.6), we can now combine this information together with conditions associated with other teeth found during the complete examination (and assessment of the appropriate radiographs). This combined information is brought together in a systematic template (comprehensive treatment planning) as seen in Fig. 8.32. This template is used so that nothing is overlooked from the initial examination. This overlap of information from the DOTA and the dental examination creates conservative, predictable treatment. The additional information gathered for our patient example came from the radiographs and dental charting as seen in Figs. 8.33 and 8.34. In this example, the primary focus for the patient was to improve the appearance of the anterior teeth, and our goal was to find conservative solutions to fulfill this focus. The treatment assessment information for our patient is

8.3 Diagnostic Occlusal Analysis TOOTH #

1 (1.8) 2 (1.7) 3 (1.6) 4 (1.5) 5 (1.4) 6 (1.3) 7 (1.2) 8 (1.1) 9 (2.1) 10 (2.2) 11 (2.3) 12 (2.4) 13 (2.5) 14 (2.6) 15 (2.7) 16 (2.8)

CHARTING

D.O.T.A.

DEFINATIVE TX

187 SEXTANT TREATMENT

FULL ARCH TREATMENT

17 (3.8) 18 (3.7) 19 (3.6) 20 (3.5) 21 (3.4) 22 (3.3) 23 (3.2) 24 (3.1) 25 (4.1) 26 (4.2) 27 (4.3) 28 (4.4) 29 (4.5) 30 (4.6) 31 (4.7) 32 (4.8)

Fig. 8.32  Comprehensive treatment planning for each tooth, sextant, and quadrant

Fig. 8.33  Full-mouth radiographs for assessment to determine if there are any dental caries, infections, and periodontal health

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Fig. 8.34  Patient’s dental charting illustrating existing restorations, decay, etc.

Table 8.8  Treatment assessment summary Assessment 1 Correct mandibular arch form 2 Correct mandibular incisal edgesd

Photography reference

(Yes/No)

Recontour and/or waxing

Treatment recommendationa,b,c

Mand. occlusal

No

None

None

Mand. occlusal Mand. anterior Mand. retracted open (anterior, left & right)

Yes

Wax in new incisal edge

Veneer restoration 32–42 (#23–#26) Composite or porcelain

3 Correct maxillary arch form

Max. occlusal Smile view

4 Correct maxillary incisal edgese Length = 10.0 mm (8.0 X 1.25) 5 Equilibration (CR = MI) Reductive Additive 6 Equilibration (excursive) Reductive Additive

Max. occlusal Max. anterior E smile, repose Tip down Lateral smile profile

Yes Yes

Recontour 11, 12, 21 (#7, #8, #9) Wax in anterior teeth to ideal proportions and length

Yes No Yes Yes

None Crowns 11, 21 (#8, #9) Veneers 12, 13, 22, 23 Gingivoplasty 11 (#8)

Equilibration

Add wax lingual 11 (#8)

Equilibration Crown 11

Correction of facial and/or incisal surface = veneer restoration (composite or all porcelain) Correction of facial/incisal/occlusal/buccal and lingual surfaces = crown restoration (PFM, gold, or all porcelain) c Correction of cusp (one or two) = onlay restoration (composite, gold, or all porcelain) d Teeth #3.3–#4.3, #22–#27 e Teeth #1.3–#2.3, #6–#11 a

b

8.3 Diagnostic Occlusal Analysis

189

summarized in Table 8.8. For the purposes of this chapter, we will separate Fig. 8.32 into the respective arches (maxillary and mandibular). Figure  8.35 illustrates the information transferred for the maxillary teeth. Here the dental charting is documented in the first column, and the data from Table 8.8 is placed into the second column. The definitive treatment in column three is taken from what was completed (altering the incisal edges and facial/lingual contours) on the mounted maxillary model as outlined in Table 8.8 (last column-treatment recommendation). The same process was completed with the mandibular arch and is illustrated in Fig. 8.36. Once column 3 in both maxillary and mandibular arches are completed (as outlined in Fig. 8.32), we can further group the procedures into sextants, and finally full arches.

Fig. 8.35  Comprehensive treatment plan for the maxillary arch for each tooth, sextant, and quadrant based on the treatment planning assessment

Fig. 8.36  Comprehensive treatment plan for the mandibular arch for each tooth, sextant, and quadrant based on the treatment planning assessment

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The advantage of doing this is to combine treatment so that the dentist can treat a combination of quadrant(s) and/or full arch treatment. This provides the dentist with options on phasing treatment and to create more efficiency and productivity to the schedule. With this due diligence, the “physician of the masticatory system” dentist understands the solutions to the dental problems and knows how to create stability. I prefer to use the term “owning the treatment plan.” This term is not meant to disregard a patient not taking ownership of their dental problems, but simply means that the dentist fully comprehends the scope and nature of the treatment plan. Owning the treatment plan requires the restorative dentist to dissect the problems and reconnect with solutions. In addition, owning the treatment plan allows the dentist to overcome any objections by the patient. This means offering alternative treatments that do not compromise the final outcome. Figure 8.37 illustrates this point as this represents an overlap of treatment acceptance that meets the functional requirements as well as the patient’s comfort (financial and emotional). This serves our patient and provides a comprehensive treatment plan in the best interest of the patient. For example, our patient did not elect to proceed with mandibular veneer restorations due to finances. As an alternative solution, composite restorations were recommended as a means for occlusal stability. Figure 8.38 illustrates the final treatment that was finally accepted by the patient. The final results of this treatment plan are illustrated later in Chap. 10 (Figs. 32, 33).

COMPLETE COMPREHENSIVE TREATMENT PLAN

DIAGNOSTIC OCCLUSAL TREATMENT ASSESSEMENT

DECAY, SIGNS OF INSTABILITY, DENTAL RADIOGRAPHS CLINICAL EXAMINATION

Fig. 8.37  Illustration of combining the diagnostic occlusal analysis with the signs of instability, charting, and dental radiographs

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Fig. 8.38  Illustration of combined DOTA with clinical examination resulting in a comprehensive treatment plan for our patient example

This mindset creates confidence in the dentist and becomes very clear during the presentation/consultation of the treatment plan. Having confidence also provides the dentist solid ground to address any questions or objections that the patient may have. In addition, should a patient elect to phase out treatment over a period of time, the dentist would not hesitate as the end point of the treatment result will be the same regardless of how much time it takes. Our next chapter will focus on this aspect of communication.

9

Communication: With Your Patient/ Specialists/Technicians

“Wise men speak because they have something to say; fools because they have to say something.” Plato

Contents 9.1  Discussion 9.2  Dentist and Patients (Primary Relationship) 9.3  Dentists and Specialists (Secondary Relationship) 9.4  Dentists and Dental Technicians References

9.1

 193  198  203  220  227

Discussion

“Communication” according to Google is “the impartment or exchanging of information or news, means of connection between people or places in particular.” This exchange of information has evolved since the beginning of civilization. From illustrations in caves to telegraphs, and telephones to emails, human civilization has constantly evolved with the advancement of technology in the methods of communication with each other. This evolution has brought changes to social behavior, which in turn changes the way people interact and communicate with each other. People communicated with hand-written letters and face-to-face conversation was the only way to interact with each other. Today, modern methods of communication now create much less or no face-to-face time, and relationships are now sometimes measured on how many “likes” or “followers” you have. In addition, companies are now able to monitor our online behavior and specifically target products that interest us. They know nothing about us except on what we “click” online. We must accept this as part of our environment, but the consequences are seen everywhere. In public settings, for example in a © Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_9

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restaurant, you will notice some patrons not speaking to each other, but rather occupied on their personal devices. Artificial intelligence is now a reality and the idea of speaking to a device certainly will again change the way we interact with each other. Unfortunately, current behavior through technology has created more isolation and less human-to-human interaction, and the art of direct (face to face) communication seems to be less and less important. As a result of this, dentists still need to effectively communicate face to face with patients even though there is less of this in society. In my years of teaching and lecturing, the subject of communication frequently comes up. One of the most frequently asked questions by dentists is “How do I communicate with …?” or “How do I explain this to my patient (or staff)?” I believe questions like these are frequently asked because dentists are programmed to communicate based on what they know which is based on their own personal history and life experiences. In the setting of a private practice, a dentist’s responsibility is to correctly diagnose, educate patients on conditions, and provide subsequent treatment. Dentists are known for having the ability of being too technical during patient conversations that involve both conditions and treatment [1]. This can in most cases lead a patient to not fully comprehending or understanding the implications of specific treatments or conditions. Although this may sound like a very simple explanation, there is certainly more to it. When dentists learn a new concept, they need to process it until it makes sense to them. Only then will a dentist feel comfortable communicating any new concept to a patient. The vast majority of dentists are amiable, want to be liked, and mostly prefer to avoid conflict (with patients and staff). These are great qualities to have, but in most cases get in the way of effective communication (as a leader and manager) not only with patients, but specialists and technicians too. As mentioned earlier, in the clinical setting, the vast majority of dentists’ nature is to be amiable and avoid conflict. This automatically puts dentists at a disadvantage when effective communication is needed. For this discussion, we will only focus on reasons outside those of personal nature (dentist’s family life, upbringing, childhood, etc.). Most dentists exhibit these characteristics, and to truly understand this, let us discuss some reasons as to why this occurs. The importance of this chapter is to help you understand that a healthy relationship between you and your patient is paramount to the success of your practice. Any breakdown of this communication can lead to patient dissatisfaction and possible therapeutic failure [2]. Every dentist remembers dental school, and no matter where you studied to become a dentist, you were taught everything necessary to pass the respective dental board examinations. One of the requirements of all accredited dental schools is to provide enough training for the students to be eventually be able to obtain dental licensure in their respective choice of residence. This description holds true for other professional schools such as medicine and law. However, leadership and communication skills are not requirements to pass dental board examinations, and thus are given little or no thought in dental schools. This certainly leaves the dental student with tremendous clinical knowledge but with little or no skills in communication or leadership. As part of the learning process, dental school students provide patients with appropriate treatment while being overshadowed by their respective professors and instructors. These same professors and instructors sometimes are not the most effective communicators and usually only focus on the student’s didactic skills. In the 4 years (most programs’ duration) of dental school, students graduate with little or no advancement in

9.1 Discussion

195

communication skills and consequently are at a tremendous disadvantage compared to other professions. Efforts are being made to help dental students enhance there communication skills with patients [3]. Another factor is the stigma attached to the profession of Dentistry. Patient’s experiences with fear and pain are mostly associated with any dental practice, and this puts our profession at a disadvantage. Patients themselves often do not communicate with dentists due to fear and/or anticipation of pain. This can be a barrier between the dentist and patient which can be very challenging. Another common significant stigma is how dentists are perceived when it comes to dealing with high stress in the work environment. Dentists still rank high (or highest) among all professionals with excessive stress and suicide. Although this is usually not related to communication, it still represents an underlying fact. Educating patients on dental conditions is the most common way dentists feel comfortable in how they communicate with their patients. Simply informing them of the facts/conditions will be enough for patients to accept treatment. I would suggest we adopt or change our mindset to better understand our patients and others involved in the decision-making process. This will certainly improve our methods of communication and improve our chances of our patients understanding the goals and desires of the treatment process. In previous generations, patients would solely rely on the opinion of what the dentist diagnosed and the respective recommendations for treatment. That was how trust was developed between the dentist and patient. Thus, the knowledge and experience of the dentist were enough for patients to make important clinical decisions. These patients solely relied on the information provided by the dentist. You could say that this was the only relevant relationship, and can be considered a primary one. However, in today’s age of instant information, most patients have formed their own opinions about procedures, outcomes, and even fees before they arrive to the dental office. This has created another challenge for the dentist, that is, understanding a patient’s opinions (and thoughts) who have done (or continue to do so) their respective research. These patients understand conditions they have, and at the same time know and understand solutions to those same conditions. They will sometimes delay treatment until they do their own research to confirm that the recommended treatment is appropriate. This does not take anything away from the relationship of trust that exists between the dentist and the patient—however dentists must consider a different approach to enhance the trust while building a long-lasting relationship. Dentists must work harder to inform patients of their needs while still building the trust and confidence for the patient to interpret that the dentist is still the expert [4]. Since the primary relationship is between the dentist and patient, a secondary relationship needs to be formed with others whose expertise will help our patient achieve the restorative goals. The secondary relationships are between the dentist and dental specialist (periodontist, oral surgeon, endodontist, and orthodontist), and the dentist and the dental lab technician/master ceramist. A tertiary relationship also exists when our patients seek care with appropriate specialists. Figure 9.1 illustrates how these three relationships are connected. It is important to note that the dentist is the central figure and ideally should be responsible for the success of the primary, secondary, and tertiary relationships. This is an enormous responsibility for the dentist, but is necessary as the outcome of the restorative treatment needs to be in control of the dentist, and no one else. This is illustrated in Fig. 9.2 where an ideal desired result

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Fig. 9.1  Primary, secondary, and tertiary relationships between dentist, patient, and specialist Fig. 9.2 Communication: Desired result/outcome when all communication is shared equally

Fig. 9.3  Communication: Patient example of desired outcome with ideal communication with dentist, patient, and specialist

9.1 Discussion

197

Fig. 9.4 Communication: Desired result/outcome shifted when less communication by dentist

Fig. 9.5 Communication: Patient example showing smile view of shifted communication as illustrated in Fig. 9.4

is achievable when there is equal input from the dentist, specialist/technician, and the patient. Figure 9.3 illustrates an example of the desired result. When the outcome leans more in control of the secondary relationships, the dentist may find frustration with the results of the final outcome. Figure 9.4 illustrates an example of little input from the dentist and too much input from the specialist. As you can see in Figs. 9.5 and 9.6, the desired result has shifted away from ideal, leaving a compromised aesthetic result. On the other hand, if there is little input from the specialist, and too much from the dentist, the desired result shifts away from ideal. Here, Figs. 9.7 and 9.8 illustrate this shift where the restorative outcome has produced a periodontally compromised result. We will discuss each of these relationships in more detail along with ways of improving the communication within the secondary relationships. In addition, improving communication with your team members is more important as this relationship needs to be on a solid foundation.

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Fig. 9.6  Communication: Patient example showing retracted views resulting from shifted communication as illustrated in Fig. 9.4 Fig. 9.7 Communication: Desired result/outcome shifted when less communication by specialist

The ultimate goal is to increase success for our patient while providing an outcome that is not only comfortable, but also predictable.

9.2

Dentist and Patients (Primary Relationship)

When I began my own practice, for several years the treatment that I recommended was primarily based on treating biological and structural issues with teeth, that is, periodontal disease, dental caries, and compromised teeth. I knew little or nothing about occlusion or function and focused my energy on treating the basic issues as mentioned above. They would simply understand and accept most or all of the

9.2 Dentist and Patients (Primary Relationship)

199

Fig. 9.8 Communication: Patient example showing E smile view resulting from shifted communication as illustrated in Fig. 9.7

recommended treatment. Truthfully speaking, this was acceptable at the time, but as outlined in my opening remarks, when my practice changed to include treating occlusion and function, I struggled with my communication skills. In the initial years of my practice I was taught by some consultants to use “scripting” as a way of getting patients to accept treatment. This worked but as I followed my Dawson journey, I started to see a decrease in my treatment acceptance. My existing method of scripting was no longer working and most importantly I realized that I was overeducating my patients out of accepting dental treatment. My challenge now was to help my patients understand their occlusal/functional problems while understanding the implications of needed treatment. To do this successfully, I needed to completely change the way I approach communication. Over the years, I have realized we should pay more attention to the emotional aspect of our patients, mindset, or just simply listen to their emotions. When discussing signs and treatment remember, dental treatments, especially aesthetic dentistry, are more about the patient’s emotional well-being. Patients are invested with their time, money, and emotions. A simple example of this is the experience of buying a car. When you are ready to purchase a vehicle, there is a good chance that you know the kind of car (make and model) and how much you are willing to spend. If someone (sales person) tries to sell you the same car with features you do not need (and were not prepared to consider) nor want, then you may feel disconnected and begin to question the intentions of the salesperson. Most likely you move on to another dealership for a better experience. This experience is directly related to how you feel, and what is in your comfort zone. It is our responsibility to understand our patient’s emotional well-being with respect to their dental conditions, as well as anything else in their life that may be significant enough to impact their treatment decision-making, especially when presenting treatment that may be complex or challenging. Thus effective communication is a complex interpersonal interaction

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requiring understanding of your patient’s emotional state [5]. There are three occasions where you must be at your best in communication: the new patient examination (patient seeing you for the first time), a new patient dental emergency, and presenting new treatment with your patient. For our discussion in this chapter we will focus on the new patient examination. If you recall back in Chap. 4, the new patient experience in the office begins with an interview between the dentist and patient. This is the first exposure that a patient has with the dentist and is the ideal opportunity for the dentist to have a constructive dialogue with the patient. This should be done in a private setting where there is no disruption, so the dentist can focus on the patient. The dialogue has three parts which are connected to create an exceptional experience for the patient.

9.2.1 Part 1 Begin the dialogue with inquiring more about why the patient is in your office. “How can I help you?” “Tell me more about why you are here.” “Tell me what you would like me to focus on.” “Tell me more about what you know about your mouth.” These questions are open ended and are geared for the patient to open up about what they know and feel about certain dental conditions. The information provided by the patient may be vague, but you need to pursue this further by asking the patient to elaborate more. “I am curious about what you meant by … please tell me more about that.” The most important part of asking any of the above questions is for the dentist to keep your mouth shut—say nothing. The idea is to be quiet and allow the patient to share their stories. While you are focused on what the patient is saying, maintain good eye contact as you want your patients know that you are paying 100% attention.

9.2.2 Part 2 The dialogue continues but now you need to know more about the emotional element of the conversation. “How does this make you feel? “Tell me how you see the final results.” “What are your expectations?” Listen carefully and make some points that are relevant to the patient’s emotional well-being. Once you understand the emotional connections of your patient, then the next step is to inquire about their expectations. What are they desiring? What is it that they are expecting you the dentist to come up with in finding a solution(s)? Remember, patients have done their research before seeing you. If I sense this, then I will ask “Has anyone talked to you about this procedure?” or “What do you know about this procedure?” Again, openended questions encourage more discussion, and remember to pay attention to what the patient is stating. This creates an opportunity for you to understand the level of their dental IQ.

9.2.3 Part 3 Once you have understood your patient’s dental priorities and their emotional connections, the next step in the conversation is to begin to educate your patient. This

9.2 Dentist and Patients (Primary Relationship)

201

entails the dentist to have a conversation about “normal” dental health. Normal dental health pertains to biological, structural, and most importantly functional health of the patient’s masticatory system. This conversation provides two benefits. First, it provides valuable information to the patient about normal dental health and how this relates to the complete examination. The examination becomes a co-discovery experience for both the dentist and patient—as they both learn more about the present conditions. At this point in the conversation, ask an important question. That is, “If we discover other conditions that you did not mention, do I have your permission to discuss them with you?” Second, it eliminates any questions or doubts about your intentions as a dentist and prevents the patient from feeling overwhelmed or disconnected after the examination. This gives an opportunity for the patient to understand the complete examination. Upon completion, the next step in this interview process is to bring a team member into the consultation room. The team member can be a treatment coordinator or, my preference, the chairside assistant. The dentist reviews the important details of the conversation to the team member and at the end verifies by asking the patient if any important information was left out. The triad is now complete and the dentist, patient, and team member all are on the same communication path leading up to the examination. The patient is then escorted and given a brief office tour on the way to the treatment room. Chapter 4 outlines the 12 steps of the complete examination. The initial interview and office tour are the first two steps in this process. The remaining steps (3–12) are simply focused on gathering data. When performing an examination, most dentists strictly focus on gathering data while not intentionally allowing the patient to be a part of the process. What is typically done is data is gathered through the hard and soft tissue exam. Executing the complete exam correctly requires using steps 3–12 to accurately gather data thoroughly. This in turn requires the dentist to be more engaged with the patient by explaining the normal conditions you are looking at each step. Document the data with your assistant and pay attention to your patient’s reaction. Look for patient nonverbal communication (eyes, patient hands, and body language) as clues that may give you indications on how your patient is feeling with the co-discovery process. This becomes more relevant when you begin to discover conditions that your patient was not aware of. If the patient has become disconnected during the examination, then it may mean that the dentist did not engage with the patient. If you sense it, then it is best to stop the exam and simply ask the patient about how they are feeling. For example, “I am sensing that you may be feeling uncomfortable, how do you feel?” Let the patient answer before moving forward, and then attempt to reengage with your patient. During the examination, it is recommended that the dentist explain or remind the patient of what you are checking for and what a normal result would look like. Thus, if your patient’s conditions deviate from normal, then as part of the co-discovery process, both dentist and patient are engaged in a conversation with each other. There is nothing worse than a patient going through a comprehensive examination, not participating or knowing what the relevance of anything is. Following this protocol will create a much better experience for both the dentist and patient. Once the examination is completed, begin your conversation by asking the patient is there was something about the exam they would like to discuss (“We have completed the examination, is there anything that you noticed that needs

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clarification?). If the patient does not need any clarification, then give them a summary of the exam findings. Start by paying attention to the dental conditions that first brought the patient into your office, and then briefly discuss other conditions related to the other parts of the examination. Reviewing relevant X-rays and corresponding intraoral photographs can help explain the relevance of what is going on. Occlusal disease is instability in the masticatory system. In situations when you feel that the patient’s masticatory system is unstable (TM joints, muscles of mastication, and signs of instability in the teeth), then your communication to the patient becomes even more critical. In most cases, patients with occlusal disease are asymptomatic and are unaware of the breakdown of their system (until symptoms arise or structural damage results in a disability). Effective communication is important for them to understand the relevance and implications of their problem. More importantly, it is important that you find out how they feel about their dental conditions, and if they are concerned about it as much as you are. For example, “I am concerned that you have worn down your front teeth, has anyone explained the importance of this?” The response to a question like this will provide you an answer to whether your patient is ready to treat complex problems or not interested at all. Remember, you the dentist are their best advocate and should only advise them on what is best for their dental health. The patient takes responsibilities for their decisions based on what information they know. Making an educated decision requires patients to understand the problem and implications of not treating it. In other words, the patient “owns” their dental problems. This does not in any way imply that we do not care about our patient’s dental issues, but it involves simply taking on the role of advisor. Like many other types of advisors, their clients make decisions based on what information is provided by the advisor. How many times have patients been so overwhelmed by dentists giving too much information on something they do not understand or want? Overwhelmed patients can feel uncomfortable as they may be questioning your integrity or motive for specific treatment. This is similar to the analogy used earlier regarding purchasing a vehicle. To avoid a patient feeling overwhelmed, I would recommend asking permission to continue a conversation. In other words, do not move on to another subject until the patient gives you permission to do so. For example, “I am sensing that you are not comfortable with what I am saying. Is that true?” “With your permission, can I explain this in a different way that may make it clearer?” These types of questions are nonthreatening and let your patient know that you are only thinking about their interests, and not yours. If your patient is not ready to solve complex problems, then document this in their records, and simply advise them that when they are ready, you will be available to help them. Remember that when creating a relationship with your patient, communication is by far the most important element in establishing trust and confidence. Improving your communication skills by asking open-ended questions will raise the curiosity and interest of your patient. This process of communication sets the groundwork for establishing a good solid relationship with your patients and most importantly building trust and respect for each other.

9.3 Dentists and Specialists (Secondary Relationship)

9.3

203

Dentists and Specialists (Secondary Relationship)

Dentists rely on the skills and expertise of various specialists including periodontists, oral surgeons, endodontists, and orthodontists. The use of specialists is solely based on the treatment plan created by the dentist. The idea of using a specialist is to provide treatment that is outside the skill set of the referring dentist. In my experience of speaking with many specialists (orthodontists, oral surgeons, and periodontists), the overwhelming feedback is that the referring dentists often do not have a clear restorative outcome before they refer the patient. Another important opinion from the specialists is that the referring dentists rely heavily on the specialist to determine the restorative outcome, especially when it comes to dental implants. I can recall an example when one periodontist showed me a referral slip and all that was written was “Dental implant #19” (or 3.6—international numbering system). What does this say about the mindset of the restorative dentist? When there is more complex restorative treatment needed, what is the level of communication from the same dentists? To be clear, all dental specialists listed above are highly skilled experts in their respective dental field. They are not experts in restoring teeth, nor should they be. The only person responsible for the restorative outcome is the referring dentist, period! Another way to look at this is to think of the restorative dentist as the architect (with the restorative design and plans) who requires the help of engineers (civil, structural, and electrical), to make the design of the structure (restorations and occlusion) not only stable, but also predictable in nature. When one looks at restorative dentistry in the same way, it is easy to appreciate how the skills of a specialist can produce amazing results. This discussion will make suggestions on how to improve the communication between the restorative dentist and specialist, particularly orthodontists and periodontists. The primary objective of any orthodontist is to move teeth to the most ideal position within the parameters of musculoskeletal system. Moving teeth can correct crowding, change planes of occlusion, and alter gingival margins which are some examples of what orthodontic treatment can accomplish. Unfortunately, these examples are usually controlled or dictated by just the orthodontist alone. Sometimes the outcome does not turn out to the best expectations. This in no way implies that orthodontists are not skilled in providing patients with great results, but it seems that just “straightening” teeth does not always result in a good functioning occlusion. Why does this occur? There are probably several reasons, but what I have found is that the most common reason is due to the restorative dentist not providing any or very little communication to the orthodontist regarding the desired outcome. What are the implications of the dentist not providing the right communication? One answer could be the end result of the orthodontic treatment can make the restorative outcome or improving the patients occlusion more challenging. This will occur often when the restorative dentist just accepts the final results from the orthodontist. The best way to improve this communication is to have the referring dentist “own the treatment outcome” by communicating the desired final outcome to the orthodontist. The first place to start is to follow the guidelines by starting to work with your models (study casts) mounted in centric relation on a semi adjustable articulator. Figure 9.9 illustrates an

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Fig. 9.9  Communication: Patient example of communication between dentist and orthodontist. Goals of anterior crowding need to be relayed to specialist

Fig. 9.10  Mandibular teeth repositioned on model to ideal arch form

example of a patient seeking an aesthetic change with some anterior crowding. Here the mandibular anterior teeth exhibit more crowding as compared to the maxillary ones. The mandibular anterior teeth are cut off the model and repositioned in rope wax and checked for ideal arch form (see Fig. 9.10). The same is also completed with the maxillary anterior teeth (see Fig. 9.11). Here both arches are more ideal and articulating them together helps determine if anything else needs to be modified (midline, etc.). The diagnostic wax-up is completed and the occlusion is perfected by equilibration (see Fig. 9.12). Altering or moving the teeth as illustrated (Figs. 9.10–9.12) in the study models is a great method for the dentist to understand what is required by the orthodontist to achieve the desired results. For more difficult cases, it is recommended to meet with the orthodontist in person to review the photography, study casts (original and modified ones), and discuss ideas of what can be accomplished. However, for other types of cases, it is recommended to provide as much information to help the

9.3 Dentists and Specialists (Secondary Relationship)

205

Fig. 9.11  Maxillary teeth are also repositioned on model to ideal arch form

Fig. 9.12  Both models are equilibrated and waxed up for final communication with orthodontist

orthodontist understand the desired outcome. This can involve sending X-rays, photographs (preclinical, and of the study models), occlusal analysis, and a letter summarizing the important details and goals. This level of communication is beneficial to the dentist as there is much to learn from the orthodontist. Sometimes, orthodontic treatment expectations can be challenging or difficult to achieve and under these circumstances the orthodontist needs to provide realistic expectations of what is possible. As you can see this can provide invaluable information and allow the dentist to be more prepared to make modifications to the restorative plan. The responsibilities of a periodontist are to provide patient care in areas of periodontal disease, placing dental implants along with soft tissue management (gingival architecture). Dental implants have become the most popular replacement of missing teeth for the past few decades. Although implant design has provided increased ­long-term success (improved osseointegration, etc.), the position and placement of the dental implant are still extremely important to the restorative success. However,

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we find a similar pattern of communication with the referring dentists and the periodontist. For example, too often a referring dentist will send a patient to their respective periodontist and simply ask them to place a dental implant in a specific area. As a result, the periodontist places the dental implant in the area best suited for the quality and amount of bone present. This position of the dental implant may not be ideal from an occlusal relationship which may indicate that occlusal forces not being evenly distributed can result in implant and/or restorative failure due to overloading. Since dental implants behave differently (as compared to natural teeth) under excessive occlusal force, restorations fail and/or vertical bone loss can be found present around dental implants. This usually is not a consequence of the surgical technique but is related to the restorative outcome along with the existing occlusion (and function). Like other dental specialists, periodontist needs guidance to understand the final outcome when definitive periodontal procedures are required. There are ways that can help improve the communication between the restorative dentist and periodontist. The goal is to help the periodontist locate the ideal place for dental implant placement so that the final restoration becomes more predictable. Use mounted models in centric relation and work out the occlusion prior to placement of a dental implant(s). For example, replacing missing teeth on the articulated models in wax to create and confirm a stable occlusion will provide reassurance that the restoration will be in the correct position. From here, a surgical stent can be made from this w ­ ax up and given to the periodontist as an ideal guide that can establish a reference to the restorative outcome. Figures 9.13, 9.14, 9.15, and 9.16 outline the process of creating predictable results. Figure 9.14 illustrates the placement of teeth (in wax) in the mandibular left posterior area showing that the position of these teeth provides ideal occlusal stops in centric relation. Figure 9.16 illustrates the provisional implant restorations in place. In this particular case, the decision was made to provide the patient with provisional restorations as a means to determine a stable occlusion before committing to final implant restorations.

Fig. 9.13  Communication: Patient example of communication between dentist and periodontist. Edentulous area requiring placement of dental implants

9.3 Dentists and Specialists (Secondary Relationship)

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Fig. 9.14  Communication: Completed model workup including positioning of new teeth in the edentulous area including idealized occlusion

Fig. 9.15  Implants placed by periodontist using a surgical guide based on the completed models. (Courtesy of Dr. Tricia Crosby, St. Charles, IL)

The other area of importance is communication with a periodontist with regard to gingival architecture of the maxillary anterior teeth. Gingival grafting and/or clinical crown lengthening are important options in the anterior areas of the smile zone to achieve harmony and balance. Again, using the mounted models, establishing the ideal proportions of the anterior teeth as well as the gingival margins, the determination of either grafting or clinical crown lengthening is finalized. Once you understand the teeth that require gingival modifications, the next step is to communicate this to the periodontist. There are four methods to communicate this: 1. Digital photography 2. Aesthetic imaging 3. Aesthetic periodontal calculation 4. Surgical stent

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Fig. 9.16  Completed provisional restorations in occlusion

Fig. 9.17 Communication: Photo illustrating another method used to relay information from dentist to periodontist. Digital photography with ideal gingival margins added

Each of these methods was written in order of preciseness, having the stent being the most precise method of all. Regardless of which method you choose, it is important to remember that the restorative dentist must be comfortable knowing where the central incisal edge is positioned and the desired clinical length of the same tooth.

9.3.1 Digital Photography Digital photography is an excellent tool to communicate the desired gingival margins. Because we are using only photos, this method usually works best when there is a normal reference in the same photo. If you have a normal reference in the same frame, then the best way to use this method is to simply mark lines of normal and desired gingival margins on the photograph. This will illustrate the location of the desired gingival margins. Figure  9.17 illustrates a great example of this method. Here the patient’s left anterior teeth (2.1, 2.2, 2.3) gingival margins appear to be normal or ideal, but the right side is not. Note that the crown lengthening teeth are

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Fig. 9.18 Patient underwent clinical crown lengthening on the maxillary right anterior teeth. Completed healing shows more symmetrical gingival margins. (Treatment courtesy of Dr. Robert Pick, DDS, MS, Naperville, IL)

Fig. 9.19 Completed restorative phase for the same patient. (Restoration courtesy of Gilbert Young, CDT, AAACD, Plano, Texas)

marked with a dotted line, while the normal gingival margins are solid. This needs to be communicated with the respective periodontist. Figure  9.18 illustrates the completed crown lengthening (with 12-week healing) procedure. Once healing has occurred, restorations can be completed as prescribed. In this case, Fig. 9.19 illustrates the completed restorations.

9.3.2 Aesthetic Imaging Aesthetic imaging is certainly another option to consider as a means of illustrating the desired results of gingival margins as well as restorations. This method can also be used when consulting patients on treatment options and outcomes. Here patients can visually see the possible outcome of treatment before ever committing. In addition, should the patient not find the aesthetic results pleasing or prefer a different outcome, imaging can be used to provide the patient their desired results. On the other hand, using any aesthetic imaging without careful planning possesses the risk of an unrealistic expectation to the patient. In turn, should the actual results differ from the aesthetic imaging, then there may be a need of further treatment (more cost and time—patient and dentist) to achieve what you created (artificially), not to mention the possibility of having a disappointed patient. One way to keep imaging realistic is to complete the work on the mounted models first and then transfer the changes made on the models to the imaging software. Figure 9.20 illustrates a patient displaying the “E smile” and showing gingival margins that are not

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Fig. 9.20 Communication: using dental imaging. Clinical case showing smile view where gingival margins are not ideal

Fig. 9.21  Using E smile and close-up photo outlining the gingival asymmetry

ideal on both maxillary central incisors. This is illustrated in more detail in Fig.  9.21. Here, the close-up view illustrates the deficiency in the height of the gingival margins of both central incisors (marked by the “blue” line). This case was evaluated using mounted models in centric relation. After calculating the width of the maxillary central incisor, the ideal length was calculated (length = width × 1.25) and marked on the model. Trimming the gingival margins on the model provides you with a visual appreciation of the final outcome. Waxing up the central incisors to create symmetry and confirm that golden proportions are adequate will complete the aesthetic workup. Figure  9.22 illustrates the six steps in creating the ideal mock-up. Using imaging software, you can duplicate the results from the model into an image that represents the goals for the patient. Figure 9.23 illustrates the imaging (left image) for this patient as well as the completion of the clinical crown lengthening (right image).

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Fig. 9.22  Pre-imaging model workup using ideal length-to-width measurements, wax-up to ideal ratios, and golden proportion. (Ruler courtesy of Bayview Dental Lab, Chesapeake, VA)

Fig. 9.23  Diagnostic workup transferred to photo using digital imaging. Crown lengthening procedure completed and closely resembles the digital imaging

9.3.3 Aesthetic Periodontal Calculation The last two methods of communication use images to relay valuable information to a periodontist. Both methods rely on the skills of the dentist (or team member) to take accurate photos, and to create a realistic aesthetic image of the desired result. The third method is the “aesthetic periodontal calculation”. Instead of relying on just images, we combine the use of digital photography and mounted models to calculate the actual

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Fig. 9.24 Aesthetic periodontal checklist as another method for communication between a dentist and periodontist

Fig. 9.25  Case example used to illustrate how the aesthetic periodontal checklist will be used. Incisal edge position and gingival margins are asymmetrical

amount of grafting or crown lengthening of the maxillary central incisors. Figure 9.24 outlines this method of calculation. Figure 9.25 illustrates a patient having multiple areas of discrepancy in tooth proportion and gingival balance. Before using the aesthetic periodontal calculation, choose the best central incisor. In this case, tooth #1.1 was chosen due to the best incisal length. The first two steps involve determining where the incisal edge needs to belong in relation to the upper and lower lips. Figure 9.26 illustrates both “repose” and “E smile” poses. These photos help determine the vertical position of the incisal edge. At the “repose” position, the patient is not exposing any of his maxillary central incisors, while the “E smile” photograph reveals that the current incisal edge position (blue dotted line) is beyond 50% distance (yellow dotted line) between the upper and lower lips. Based on this observation, the vertical position of the incisal edge will not be lengthened but will remain the same. Figure 9.27 illustrates the first two steps completed in the aesthetic periodontal calculation. Next, using digital calipers measure the existing width and length of both maxillary central incisors. Figure 9.28 illustrates that the length of tooth 1.1 is significantly longer than 2.1 due to the incisal edge and gingival margin differences. If this patient did not have any diastemas that needed to be closed, we would simply take the existing width of the selected central incisor and multiply it by 1.25 (the factor for ideal length-to-width proportions). However, in our patient example, we are planning to close the spaces which means that we need to consider a new width, and subsequently

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Fig. 9.26  Comparison of “E smile” and “repose” and determining the incisal edge position

Fig. 9.27  Aesthetic periodontal checklist: Steps 1 and 2: Determine the vertical incisal edge position

a new length. When considering widening anterior teeth (especially central incisors), the easiest way to determine the ideal width is to use a golden proportion ruler (Bayview Dental Laboratories). Figure 9.29 illustrates our patient’s maxillary model on two different golden proportions. Based on the current arch form on the patient’s model, widening the central incisors to 8.5  mm is the best option as compared to 9.0 mm. Using this new width, we can now complete steps 5 and 6. Our new width is now multiplied by the factor of 1.25 which produces a new length of 10.63 mm. This

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Fig. 9.28  Aesthetic periodontal checklist: Steps 3 and 4: Measure current length and width of maxillary central incisors

Fig. 9.29  Restorative correction involves closing diastema, thus increasing width. Confirming ideal new width using golden proportion ruler

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Fig. 9.30 Aesthetic periodontal checklist: Steps 5 and 6: Calculating the ideal length and subtracting from current length

Fig. 9.31 Aesthetic periodontal checklist: Steps 6 and 7: Determine if incisal edge needs to be changed and determine whether crown lengthening or grafting is needed

is now the ideal length for the maxillary central incisors. Figure 9.30 illustrates this calculation in step 6 by calculating the difference between the new length and existing one. Here step 6 reveals that the maxillary right central incisor needs to be lengthened by 0.83 mm, while the corresponding left incisor needs to be increased by 1.53 mm. The next decision is to lengthen either the incisal edge or the crown. Figure  9.31 illustrates the completed calculations in steps 7 and 8. Since the decision was made to use the existing incisal edge of tooth #1.1, raising the gingival margin of tooth 1.1 by 0.8 mm would produce the desired length. The incisal edge of tooth 2.1 also needed to be lengthened to match tooth 1.1, and based on the model, this added length was approximately 0.5 mm, as outlined in step 7. The remaining difference between lengthening the incisal edge and the amount of increased tooth length is needed for crown lengthening. Step 8 in Fig. 9.31 indicates that crown lengthening of 1.0 mm be

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completed on tooth 2.1. In addition, Fig. 9.31 also illustrates the new gingival margins based on what was calculated for both maxillary central incisors. This information is valuable as it indicates the need for additional treatment including gingival grafting on teeth #1.3, #1.2, and #2.3. Prior to the patient seeing the periodontist, the incisal edges were bonded with composite to assist the periodontist with the tissue alterations. With the correct incisal edge in place, the periodontist just needs to measure ideal length starting from the incisal edge and extend the gingival margin. Figure 9.32 illustrates the completion of the tissue grafting and crown lengthening. Here, tissue symmetry has improved creating the ideal opportunity to begin the restorative phase. Using the new tissue levels, a diagnostic wax-up was completed and confirmed for size and function. Figure 9.33 illustrates the wax-up, as well as confirms the ideal golden proportion with the maxillary central incisors set at 8.5 mm, as well as idealized occlusal contacts along with anterior guidance. Following appropriate preparation, provisional restorations are finalized and approved by the patient as outlined in Fig. 9.34. The final restorations in this case are illustrated in both Figs. 9.35 and 9.36. The final results for this patient were successful based on clear communication between the restorative dentist and periodontist. This collaborated vision starts with understanding the aesthetic parameters and restorative outcome. This method does Fig. 9.32  Grafting and crown lengthening completed as per calculations. (Courtesy of Dr. Robert Pick, DDS, MS)

Fig. 9.33  Post-periodontal surgery diagnostic records, wax-up, and occlusion worked out

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Fig. 9.34  Approved provisional restorations completed

Fig. 9.35  Final restorations completed and cemented. Gingival margins, papilla, and restorations are symmetrical. (Courtesy of Hi-Point Dental Laboratory, Rolling Meadows, IL)

require diligent effort by the restorative dentist, but the calculations will certainly provide more accuracy as compared to the first two options of communication.

9.3.4 Surgical Stent This method combines photography and the use of mounted models to create a modified version. The point of working on the models is to create an outcome that illustrates the best results. A stent can be fabricated (clear suck-down technique over a model) that can be used by the periodontist to verify and finish the gingival margins to

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Fig. 9.36  Final restorations in place with final photos. Both vertical and horizontal positions of anterior restorations are ideal

Fig. 9.37  Communication: Case example using surgical stent. Pre-op photos and diagnostic workup to create ideal gingival margin

the desired location. Figure  9.37 illustrates a patient who is seeking an aesthetic improvement. Here there is clearly asymmetry with the gingival margins of the maxillary canine (recession) and central and lateral incisors. A wax-up is created to mark the desired location of the gingival margins. Figure 9.38 illustrates the grafting completed on the maxillary canine teeth, and after healing the surgical stent is in place to not only confirm the new gingival margins of the canine teeth, but also outline the desired gingival margins of the maxillary right central and lateral incisors. Figure 9.39 does illustrate the crown lengthening completed along with 6 weeks of healing. The use of a surgical stent does help the communication between the dentist and periodontist; however, time is required by the dentist to visualize the result and create a stent.

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Fig. 9.38  Surgical stent fabricated from diagnostic workup and used to determine crown lengthening. (Courtesy of Dr. Robert Pick, DDS, MS)

Fig. 9.39  Completion of crown lengthening and grafting. Post-op healing reveals improved aesthetic outcome of gingival tissues. (Courtesy of Dr. Robert Pick, DDS, MS)

Besides these methods outlined above, digital scanning can also be used to create the ideal gingival changes and print a clear surgical stent. Although all these methods will create a predictable result, communication with the respective specialist also needs to be clarified as to which method is the most comfortable one. This discussion is not intended for the dentist to impose a method on any specialist, but to provide options for the specialist to choose from. It is important to remember that no matter which option you choose to communicate with, the restorative dentist is the responsible person of the restorative case, and this information must come from the dentist.

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Dentists and Dental Technicians

Working with the right dental laboratory technician requires trust and respect. Successful relationships with dental technicians take time and patience, but the underlying strength in this relationship is based not only on the skill levels of both dentist and technician, but primarily on communication. A simple example of communication is a “final impression.” If the margins are weak or contain voids (most common complaints of technicians) in the final impression, and the technician moves forward with providing a restoration, then the dentist will receive a restoration with very little marginal integrity. In this example, the expectations of both the dentist and technician are below the standards of care. They both accept a poor impression, but the dentist expects a perfect result. If the restoration does not fit, then ultimately there will be valuable lost chairside time (by retaking a new impression), not to mention the inconvenience of the patient. This unique relationship is much like a successful marriage. It requires great communication, respect, trust, and willingness to grow together. One way this relationship can strengthen is that both dentist and laboratory technician need to support each other by providing an exchange of valuable information for a successful restorative outcome. A dentist needs to share their respective philosophy when it comes to restorative treatment, and make sure that the technician understands this clearly. This can include either quadrant or full arch impressions, or whether the dentist wants models mounted on a semi adjustable articulator. In addition, the technician also needs to express what is expected from the dentist in order to produce a successful restoration. This can include diagnostic wax up, preparation design, and shade selection [6]. For the purpose of this chapter, we will focus on a method of communication between the dentist and laboratory technician in designing the ideal contours of anterior teeth. Remember, the dentist is responsible for the outcome of any restoration(s), and the onus is to help the technician duplicate the results for our patient. If we want our technicians to pay attention to detail, then it is the responsibility of the dentist to guide them into understanding the details and expectations. The method begins with a firm foundation of occlusion and functional design, that is, starting with a stable, repeatable joint position (centric relation) and creating anterior restorations that harmonize the anterior occlusion to provide protection to the posterior teeth during functional movements. It is a known fact that most laboratory technicians get frustrated when there is inadequate preparation. If you want to start with great communication with your technician, then begin with ideal and adequate tooth reduction. Preparation design starts with proper planning that is based on mounted models in centric relation. Figure 9.40 illustrates the beginning stages of obtaining records and mounting the models in centric relation using a semi adjustable articulator. The final wax-up needs to fulfill aesthetic and functional requirements, and Fig. 9.41 illustrates acceptable aesthetics in the maxillary and mandibular teeth. In addition, equilibrated models with anterior guidance provide ideal function. With this confirmed wax-up, preparation stents can be fabricated, and will serve as our way of knowing that adequate reduction is complete. Figure 9.42 shows how the stents are used to confirm reduction

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Fig. 9.40  Communication: Dentist and laboratory technician. Case example of patient with mounted models in centric relation

Fig. 9.41  Diagnostic occlusal treatment analysis completed. Ideal incisal edges waxed up; models equilibrated

(facial, incisal, and lingual). Here, the mandibular anterior teeth are being prepared for veneers while the maxillary central incisors for full-coverage crown restorations. Stents are also used to fabricate ideal provisional restorations; we are also designing the prototype restorations based on the same wax-up. Figure 9.43 illustrates the steps using the provisional material (Ivoclar Vivadent-Telio BL3, Amherst, NY) and stents to create our provisional restorations. These are then

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Fig. 9.42  Silicone putty stent fabricated from waxed-up models for verification of adequate preparation and reduction

Fig. 9.43  Fabrication of provisional restorations using the stents of the diagnostic models

trimmed, and occlusion verified. Phonetics, aesthetics, and function are verified before dismissing the patient. Patient is instructed to return to the office after several days for approval of the provisional restoration. This provisional approval is based on three fundamental parts, aesthetic, phonetic, and functional. The process of the approved provisional restorations is discussed in more detail in Chap. 10 with examples of the approval process with respect to aesthetics, phonetics, and

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Fig. 9.44  Photographs of approved provisional restorations after aesthetics, phonetics, and function have been confirmed

function. The communication now continues with transferring the information of the provisional restorations to the laboratory technician. The following items are recommended for adequate communication with laboratory technician: 1 . Models of provisional prototypes mounted in centric relation. 2. Bite registration. 3. Pre-op photos. 4. Final photos of provisional restorations (same photos as pre-op, see Chap. 5). See Fig. 9.44. 5. Shade selection photos (color and black/white) including stump shades of preparations. See Fig. 9.45. 6. Prescription detailing shade, shape, texture, and translucency. It is important to note that the patient is equilibrated (equal-intensity contacts along with anterior guidance) and now has a perfected occlusion with the provisional restorations. Thus, centric relation is now the same as maximum intercuspation. Mounting the provisional models using a facebow and bite registration (with patient’s equilibrated bite) will provide an accurate record of the relationship between the temporomandibular joints and the maxillary and mandibular teeth. The technician now has all the information needed to copy the provisional prototype. Remember, by now your patient has been equilibrated and all the functional details have been worked out using a semi adjustable articulator. From here, two silicone matrices made (by the dentist or technician) are critical in helping the technician design anterior teeth. One is used to communicate the location of the incisal edge in both vertical and horizontal planes, while the other to duplicate the lingual surfaces of the anterior teeth. The first silicone matrix is made from the occlusal surfaces of

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Fig. 9.45  Shade photographs taken of pre-op, preparation, and black/white photos sent for shade “value”

the posterior teeth and is extended to include the incisal edges of all the anterior teeth. This matrix can be transferred to the preparation die and used by the technician to finish the incisal edge position. The second matrix is designed using the provisional prototypes, and the incisal guide table on the semi adjustable articulator. Chapter 10 discusses these stents in more detail along with illustrations showing the significance of these stents on preparation design as well as quality control of the final restorations. In addition, the mounted provisional models can also be used to cross mount the master die enabling the technician to have an accurate representation of the occlusion. When the restorations finally are completed, it is important for the dentist to verify that the technician has followed the incisal edge and contours of the prototype. In the next chapter, we will discuss the process of how to implement quality control with completed restorations. Figure 9.46 illustrates the completed restoration on the master die(s). The image on the right represents the same photo but with a polarized filter in place to remove glare from the flash. Here you can appreciate the translucency of the incisal edges of both maxillary and mandibular restorations. This does not become truly more apparent until the restorations are tried in the mouth. It is recommended that a water-soluble glycerin try-in paste be used to simulate the shade effect of the restorations when placing the restorations. Figure  9.47 illustrates all the restorations in place using Variolink Esthetic try-in paste (neutral shade). This try-in paste has the same optical properties as the final cement used (Variolink Esthetic LC-Neutral). This reassures that the shade seen in Fig. 9.47 will be the same once cementation is completed. Here, the shade of the restorations is complementary to the remaining dentition and this is evident in Fig. 9.47 with the photo taken using the polarized filter. Finally, there is nothing more stressful in dentistry than beginning a complex procedure and forgetting something important or overlooking something that impacts the outcome. This happens but can be avoided with more effective communication between the dentist and their respective chairside team member. One way to

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Fig. 9.46  Final restorations verified on mounted master models. (Courtesy of Nelson Rego, CDT, AAACD, Santa Fe Springs, CA)

Fig. 9.47  Final restorations inserted with try-in paste for verification of shade

improve this communication between the dentist and the respective team member is to rehearse the procedure a day before the patient is scheduled. A nice way of doing this is to create a procedure checklist. This is created by the dentist and is reviewed with the team member prior to the actual procedure. The idea for creating the procedural checklist is to avoid missing important steps and allow the procedure to flow in an orderly manner. This certainly reduces the stress and keeps both dentist and team member accountable to each other. Figures 9.48 and 9.49 illustrate the exact sequence of events that took place during the preparation phase of treatment. Each

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Figs. 9.48 and 9.49  Communication: Dentist and chairside. Procedure checklist created to keep the procedures moving without overlooking any steps

step is meaningful and follows a logical process. Please review the steps to follow the process from start to finish. This process described above is at the heart of what predictable dentistry is all about. Careful planning and effective communication lead to restorations that fit within the boundaries of the masticatory system while providing optimal function and aesthetics. The dentist is the guiding force in providing enough information to the laboratory technician so that restorations produced stay within these boundaries while giving optimal aesthetics and function. This level of communication between the dentist and laboratory technician is crucial to the completion and success of the treatment (Fig. 9.50).

References

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Fig. 9.50  Final photos taken of restorations

References 1. Preston JD (1982) Communication, alienation, or confusion. J Prosthet Dent 48(5):599–606. 2. Schabel RW (1969) Dentist-patient communication—a major factor in treatment prognosis. J Prosthet Dent 21(1):3–5. 3. Anders PL, Scherer YK, Hatton M, Antonson D, Austin-Ketch T, Campbell-Heider N (2016) Using standardized patients to teach interprofessional competencies to dental students. J Dent Educ 80(1):65–72. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/26729686 4. Roth S (2008) No stones unturned: essential skills of facilitation. Prosynergy Corporation, Brooksville, Florida. USA 5. Kee JWY, Khoo HS, Lim I, Koh MYH (2017) Communication skills in patient-doctor interactions: learning from patient complaints. Health Prof Educ 4(2):97–106. https://doi. org/10.1016/j.hpe.2017.03.006 6. Mamaly R, Domenico C, Pascal M (2008) Diagnostic mock-ups as an objective tool for predictable outcomes with porcelain laminate veneers in esthetically demanding patients: a clinical report. J Prosthet Dent 99(5):333–339. https://doi.org/10.1111/jerd.12333

Preparation, Planning, and Quality Control

10

“The only person you are destined to become is the person you decide to be.” Ralph Waldo Emerson

Contents 10.1  S  trategy: Treatment Planning, Presentation, and Acceptance 10.2  Execution: Teeth Preparation, Provisionals, Communication with Dental Labs 10.3  Finish Line: Quality Control, Delivery of Restorations

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The practice of dentistry has been and still is one of the most stressful among all other healthcare professionals. There are more than a few reasons for this, but one of the most frustrating events in our profession is when a procedure does not go as planned. Dr. Peter Dawson has an amazing statement: “Failing to plan, is planning to fail.” This is most profound and true. We work in a small environment, and the teeth we treat usually involves millimeters of preparation. The successful art of dentistry involves many skills such as being an “architect,” “engineer,” and an “artist,” just to name a few. However, being a successful architect or engineer requires a vision, careful planning, collaboration, and predictable execution. If the practice of dentistry is much like these other professions, then why do we not practice with a vision, careful planning, and execution? The answer lies with the type of dentist you are! A “tooth-by-­tooth” dentist is just that: a dentist that only treats teeth, and nothing else. This type of dentist performs with limited or narrow vision, basic planning, little or no collaboration, and little or no predictability. On the other hand, a “complete comprehensive” dentist is a visionary (can “see” a final outcome during an examination), who carefully plans (diagnostic occlusal treatment assessment),

© Springer Nature Switzerland AG 2020 N. Khanna, Functional Aesthetic Dentistry, https://doi.org/10.1007/978-3-030-39115-7_10

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collaborates (with other specialists), and executes treatment (predictable preparations, provisional restorations, and final results). Why is there such a contrast between these two types of dentists? One reason may be related to the mindset and attitude of each type of dentist. The same thing can be said for any professional athlete. What separates great athletes from average ones is the mindset and attitude. There are many similarities between this mindset (of the complete comprehensive dentist) and that of a professional track-and-field athlete. Both have similar goals in how they complete the track (process of complete treatment) and eventually how they come to the finish line. Both require sound discipline and a dedication to excellence (Fig.  10.1). Table  10.1 provides a summary of the similarities of both the comprehensive dentist and the athlete. The preparation, planning, and quality control of the final treatment outcome stem from having discipline in all five “similarities” as outlined in Table 10.1. This continuity of discipline is critical for each of the five parts as they are all connected to and dependent on each other. The success of each “similarity” is dependent on the previous one. If the final outcome did not result in a predictable result, then a lack of discipline occurred somewhere between “training” and “execution” sections in Table  10.1. For example, if the diagnostic records were not accurately taken in “training” then working through the “strategy” process will create an inaccurate outcome on the diagnostic models. Transferring the information from the completed Fig. 10.1 Mindset comparison of complete dentist and professional track-and-field athlete

TRAINING PREPARATION STRATEGY + + +-

EXECUTION FINISH LINE START

FINISH

Table 10.1  Similarities between complete dentist and an athlete Similarities Training

Complete dentist Complete examination Diagnostic records

Preparation

DOTA

Strategy

Treatment planning Treatment presentation Treatment acceptance Tooth/teeth preparation Provisional restorations Communication with lab Quality control Deliver restorations Predictable results

Execution Finish line

Track-and-field athlete Practice Exercise Diet Mental Physical Weather Starting position Other athletes Timing of start Pace Sprint Successful finish

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diagnostic models to the mouth will also be inaccurate. The created design is based on inaccurate diagnostic records and will have a profound impact on how teeth were prepared (execution phase—amount of reduction, etc.), along with the design of the provisional restorations (execution phase). To correct these inaccuracies in the mouth, the provisional restorations will have to be modified to create an ideal occlusal scheme before the final restorations can be fabricated. Sometimes modifying the inaccurate provisional restoration leads to perforations (on the lingual surfaces on the maxillary anterior teeth and/or facial/incisal surfaces of the mandibular anterior teeth). To correct this, the dentist will have no choice but to modify the preparation so that a provisional restoration will have adequate thickness which in turn provides the laboratory technician enough space to create the final restoration(s). Similarly, with the athlete, if there is a lack of discipline in the “training” (practice, exercise, diet), then the final outcome at the “finish line” will most likely be less desirable. The last three “similarities” from Table 10.1 (strategy, execution, and finish line) will be discussed in more detail.

10.1 S  trategy: Treatment Planning, Presentation, and Acceptance The treatment planning process begins with a complete comprehensive examination. This examination involves 12 steps and completing the first 10 will determine whether your patient has stability with structure and/or function. Remember, we define instability in the structure of teeth as observing signs of breakdown such as wear, cracks, abfractions, and mobility. Instability in function shows signs such as temporomandibular joint disorders, tenderness to any of the muscles of mastication, centric relation to maximum intercuspation differences, and poor occlusal relationships during excursive movements. Any instability with structure and/or function will require the completion of the final two steps in the comprehensive examination, diagnostic records (perfect impressions, centric relation bite records, facebow transfer) and digital photography. Once models are mounted in centric relation onto a semi adjustable articulator, the diagnostic occlusal treatment assessment (DOTA) can be completed. This consists of completing both occlusal analysis (see Table 10.2) and treatment assessment (see Table 10.3). Here, modifications to any teeth to create Table 10.2  Occlusal analysis 1 2 3 4 5 6 7 8

Assessment Verify first point of contact in CR on models Pin setting between CR and MI Mark lower and upper incisal edges R-working//L-balancing interferences

Analysis Teeth #: Discrepancy (yes/no) __mm Thin/normal/wide Yes/no  R—W teeth #:       L—B teeth #: L-working//R-balancing interferences Yes/no  L—W teeth #:       R—B teeth #: Protrusive interferences Yes/no  Teeth #: Evaluate maxillary and mandibular archform anterior/posterior Narrow/normal/widea Evaluate maxillary and mandibular anterior crowding Slight/moderate/severea or none

Consider orthodontics as an option

a

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Table 10.3  Treatment assessment Assessment

Photography reference

1 Correct mandibular arch form

Mand. occlusal

2 Correct mandibular incisal edgesd

Mand. occlusal Mand. anterior

3 Correct Maxillary arch form

Max. occlusal Smile view

4 Correct Maxillary incisal edgese

Max. occlusal Max. anterior

(Yes/No)

Recontour and/or waxing

Treatment recommendationa,b,c

5 Equilibration (CR = MI) Reductive Additive 6 Equilibration (excursive) Reductive Additive

Teeth #3.3–4.3, #22–27 Teeth #1.3–2.3, #6–11 c Correction of facial and/or incisal surface = veneer restoration (composite or all porcelain) d Correction of facial/incisal/occlusal/ buccal and lingual surfaces = crown restoration (PFM, gold, or all porcelain) e Correction of cusp (one or two) = onlay restoration (composite, gold, or all porcelain) a

b

a stable occlusion are documented (see modification description in Fig. 10.2). The complete treatment planning process now combines what was documented during the clinical examination (each tooth) to the DOTA to create the definitive treatment. This is illustrated in Fig. 10.2 with the first three columns (charting, DOTA, and definitive treatment). In Fig. 10.2, the mandibular and maxillary arches are broken down into sextants. The anterior teeth are highlighted (yellow) as they are critical in providing a stable occlusion through anterior guidance. The treatment analysis (Table 10.3) begins with the anterior teeth, regardless of the amount of treatment required to create a stable occlusion. This is important. Combining definitive treatment for each sextant condenses treatment items (column 4) and finally summarizes with complete treatment for both maxillary and mandibular arches (column 5). This would complete the restorative plan needed to create a stable occlusion while addressing the patient’s aesthetic and/or functional concerns. Complete treatment plans may consist of a few or many dental procedures needed to create stability (structure and function). Sequencing (the order of treatment) the treatment plan items generated in Fig. 10.2 (column 4) is just as important as the plan itself. The determining factors of why treatment plans are sequenced can be related to the amount of treatment needed, patients’ priorities, and budget. The latter (patients’ budget) is the most common reason that affects the sequencing of the ideal treatment. Regardless of the patient’s priorities

10.1 Strategy: Treatment Planning, Presentation, and Acceptance TOOTH # 1 (1.8) 2 (1.7) 3 (1.6) 4 (1.5) 5 (1.4) 6 (1.3) 7 (1.2) 8 (1.1) 9 (2.1) 10 (2.2) 11 (2.3) 12 (2.4) 13 (2.5) 14 (2.6) 15 (2.7) 16 (2.8)

CHARTING

D.O.T.A.

DEFINATIVE TX

SEXTANT TREATMENT

233 FULL ARCH TREATMENT

17 (3.8) 18 (3.7) 19 (3.6) 20 (3.5) 21 (3.4) 22 (3.3) 23 (3.2) 24 (3.1) 25 (4.1) 26 (4.2) 27 (4.3) 28 (4.4) 29 (4.5) 30 (4.6) 31 (4.7) 32 (4.8)

*1-Correction of Facial and/or incisal surface = Veneer Restoration (composite or all porcelain) **2-Correction of Facial/Incisal/Occlusal/ Buccal & Lingual surfaces= Crown Restoration (PFM, Gold, or All porcelain) ***3-Correction of Cusp (one or two) = Onlay Restoration (Composite, Gold, or All porcelain)

Fig. 10.2  Comprehensive treatment planning of both arches, sextants, and full arch treatment

and/or budget, the stability of the anterior teeth takes precedence, and this may also affect the sequencing of the complete treatment plan. For example, a patient may want to extend treatment over a number of years based on budget, and thus the challenge is to create stability in the occlusion over the period of time until the definitive treatment is completed. Composite is a great way to create stability when sequencing treatment over time. Composite is more cost effective (as compared to more definitive treatment like a veneer), but can change or need replacement over time. This provides your patient with an option and appreciation of a stable occlusion. Over time, we maintain this stable occlusion as treatment is sequenced over time. In our patient’s case, the DOTA revealed that the lower anterior teeth were modified to provide better function, but the patient could not afford to restore these teeth with definitive restorations. As a result, composite restorations were an acceptable way to create stability for now. This clinical case was sequenced as follows: 1 . Composite restorations on mandibular anterior teeth 2. Full-mouth equilibration 3. Restore maxillary anterior teeth

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A procedure checklist is a great way to help sequence the actual appointment time as a way of being thorough by not skipping steps. This was discussed in Chap. 9 with examples of procedure checklists. At this point the dentist has worked through the analysis process and has a great understanding of the problems as well as the solutions. I call this process “owning the treatment plan.” What this means is that the dentist takes ownership of the treatment plan as a way of being so thorough that any objections and/or questions can be easily addressed with the patient. The knowledge of treatment planning creates ownership by the dentist perfectly suited for the next step, presenting the treatment to your patient. The case presentation is an important time for both the dentist and patient. The dentist has dedicated both time and effort into creating a comprehensive treatment plan while the patient anticipates the dentist recommendations. This is the time where the dentist has full confidence and control of the treatment plan. It is recommended that the following be present during the treatment presentation: 1 . Two sets of mounted models—one untouched and the other modified 2. Printed Tx plan with fees 3. Computer with access to digital photos 4. Power point presentation (optional) Two sets of mounted models (on semi adjustable articulators) are recommended as a way to show your patient that the analysis has been completed to solve the occlusal/aesthetic problem(s). This is a great way to support the predictable method used to solve occlusal and aesthetic challenges. Both sets of models must be clean, and neatly presented. The use of a computer during the case presentations can be helpful when reviewing patient photos and radiographs. Aesthetic imaging is a great way to show a patient the potential outcome of treatment based on the DOTA It is recommended to use a power point format to present aesthetic imaging. This elevates the presentation experience for the patient. Begin the case presentation by reviewing why the patient came to see you in the first place, and mention any specific issues they had addressed during the initial interview. Remind patient of the boundaries or priorities that they mentioned during the initial interview and/or during the comprehensive examination. Briefly summarize the examination by addressing both structure and function, and be sure to make the connection with the initial reason as to why they came to see you in the first place. This is powerful as it tells the patient that you paid attention and listened to their initial concern(s). During the consultation, prior to moving on to another subject, always ask the patient if they have any questions or concerns before discussing the next item. Summarize for the patient the overall treatment plan, then present the fees, and discuss any issues or concerns before the financial arrangements are finalized. The financial arrangements can be handled by another team member. Treatment acceptance has little to do about the technical components of the treatment plan, but has everything to do with the emotional experience of the patient. This experience is related to how the patient feels about the office experience

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including the team members and environment. In addition, the confidence of the dentist has a profound impact on treatment acceptance. Having the dentist “own” the treatment plan creates or gives the patient the impression that the dentist is not only competent but also confident in the proposed treatment plan. Any hesitation or reluctance by the dentist can be perceived as less confidence.

10.2 E  xecution: Teeth Preparation, Provisionals, Communication with Dental Labs The completion of the treatment planning process provides valuable information to share with the patient. Figure 10.3 illustrates the workflow from the comprehensive examination to the eventual treatment acceptance. Once the patient has accepted the treatment plan, the next step is to execute preparation design in a predictable way. This is the planning phase and is critical because it will dictate the design of your preparations and provisional restorations. Figure 10.4 outlines the flow and sequence from treatment acceptance to laboratory communication. Upon treatment acceptance, the modified models (final outcome with stable occlusion, etc.) that were presented to the patient can be finalized by improving the detail and anatomy (Fig. 10.5). This can be completed by a dental laboratory technician or the dentist. Figure  10.6 shows an example of models completed by the author and then sent along with photographs to the laboratory (CMR Dental Laboratory—wax-up was completed by Pasha CDT, AAACD) for final wax-up. In this case, the wax-up was done digitally on the scanned master cast. The completed mockup is a representation of the final restorative outcome, and now becomes the template. We use this template to create a custom impression tray, and three different silicone putty stents.

Fig. 10.3  Comprehensive examination including DOTA as well as treatment planning, presentation, and acceptance

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Fig. 10.4  Illustrating flowchart on preparation, previsualization, and laboratory communication

Fig. 10.5  Two sets of models used in patient communication. Pre-op and completed analysis model outlining which allows the dentist to explain the steps involved in stabilizing the occlusion

They are incisal, facial/lingual reduction stents (see Fig. 10.7), and a provisional matrix (see Fig. 10.8). Figure 10.9 illustrates how both the incisal and facial/lingual reduction stents are used to verify proper reduction. The inside of the provisional matrix also contains light-body material for added detail of anatomy of the wax-up. You will notice that the provisional matrix stent was also made with the opposing arch in articulation. Figure 10.8 illustrates the fabrication of the provisional matrix. Note that when making this silicone putty matrix the opposing arch does not need

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Fig. 10.6  Dentist initial diagnostic workup. Laboratory digital wax-up (courtesy of CMR Dental Lab, Great Falls, Idaho)

Fig. 10.7  Fabrication of silicone putty reduction stents

to fully engage into the material. Simply make sure that the incisal edges and the buccal cusps are visible in the putty. When seating the filled matrix, the opposing arch can close into the provisional matrix, and allows the patient to apply even occlusal pressure while the material is setting. Figure 10.10 illustrates the dispensing of the provisional material into the provisional matrix, and having the patient

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Fig. 10.8  Steps in making silicone putty matrix for fabrication of provisional restorations

Fig. 10.9  Reduction stents used to confirm adequate preparation design

bite to keep it stable. The provisional restorations are adjusted to remove excess material as well as for contour. The occlusal contacts are confirmed, equilibrated to provide a stable occlusion and function (equal-intensity contacts in centric relation, and disclusion of posterior teeth during excursive movements). Finally, the provisional restorations are verified for phonetics by having the patient count out loud (“51–55,” “31–35,” and “61–66”). The patient is asked to return for final adjustments and confirming the aesthetics, function, and phonetics. Impressions of the provisional restorations are taken and mounted on a semi adjustable articulator. Upon the patient’s approval of the provisional restorations along with the approval

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Fig. 10.10  Fabrication of provisional restorations using the silicone matrix

Fig. 10.11  Digital photographs of approved provisional restorations

of the dentist (phonetics, occlusion, and aesthetics), the following will need to be sent to the dental laboratory: 1 . Mounted models of provisional restorations in centric relation 2. Full series of photographs of the provisional restorations (see Fig.  10.11— approved provisional photographic series) 3. Full series of preoperative photographs (from DOTA) 4. Photographs of shade tabs for both stump and final shade 5. Final impression(s) 6. Bite registration (to cross mount prepped model to opposing)

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Fig. 10.12  Laboratory communication with written instructions

7. Silicon putty matrix duplicating incisal edge and lingual contour of the provisional restorations 8. Articulator (if needed) 9. Prescription outlining the goals of the restorations along with any specific instructions that will increase the success (see Fig. 10.12—letter written to laboratory technician outlining any concerns) The nine items listed above will give the technician all the information needed to fabricate restorations that will feel very comfortable to the patient. In addition, since the teeth preparations were verified, the technician will not have any issues with inadequate space to fabricate restorations.

10.3 Finish Line: Quality Control, Delivery of Restorations Before delivery of the final restorations, proper quality control is essential especially when anterior restorations are involved. The quality control assures the dentist that the technician is following the prescription. It is advisable to do quality control immediately upon receiving the restorations. Should there be any issues noted, the technician can modify the restorations in time before the patient’s scheduled time for final delivery. There should be five points of interest when checking for quality control: 1 . Incisal edge position 2. Lingual contours

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3 . Anterior teeth symmetry between the right and left sides 4. Color match 5. Proximal contacts The maxillary central incisal edge position has both a vertical and horizontal component. This position has been worked out in the provisional restoration. Using the incisal index from the provisional model, it can be placed against the restorations on the master cast. Figures 10.13 and 10.14 illustrate how the mounted master cases can be used to verify the incisal edges. Here the incisal edges of the maxillary anterior restorations fit exactly into the silicon putty incisal index. To

Fig. 10.13  Final restorations completed (CMR Dental Laboratory, Idaho Falls, Idaho)

Fig. 10.14  Quality control: verifying incisal edges of maxillary anterior teeth

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verify the lingual contours (cingulum to incisal edge) of the maxillary central incisors, the same incisal edge index can be cut in a sagittal plane, placed onto the anterior restorations. Figure 10.15 illustrates the cross-sectional view of this relationship of the index to the lingual contour of the restoration. Again, when final restorations are completed correctly by a skilled laboratory technician, lingual contour of the restorations should fit into the silicone index. Verifying the incisal edge position and contours of the lingual side will provide a much more comfortable transition from the provisional stage to the final restoration stage. Symmetry is broken down into three categories: axial inclination, incisal embrasures, and width and height of corresponding restorations. Figures 10.16 and 10.17 illustrate

Fig. 10.15  Quality control: verifying the lingual contours of maxillary anterior teeth

Fig. 10.16  Quality control: verifying symmetry in the axial inclination and incisal embrasure spaces

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Fig. 10.17 Quality control: verifying symmetry with the width and height of anterior restorations

how beautiful restorations (including texture, translucency, and contours) can look when the axial inclinations, incisal embrasures, and dimensions are symmetrical to the respective teeth. Color matching and proximal contacts are best confirmed in the mouth. The above method of verifying your final anterior restorations should be implemented routinely. Do not compromise on any of the five quality control items so that your integrity to provide your patients with the best possible outcome is paramount. Once the quality control has been verified, the next step to complete the treatment is to permanently delivery the final restorations. The process of final cementation of aesthetic restorations is one of the most important and stressful (for the dentist and assistant) procedures in the practice of dentistry. One would explain this as getting only one chance to get it “right”; that is, the cementation process must absolutely be error free. Both the assistant and dentist need to be on same level of communication during this process, and attention to detail is paramount. Too many cases finish poorly due to errors in the cementation of anterior restorations (Figs. 10.18 and 10.19). The author recommends the following steps when delivering final anterior restorations (metal-free restorations): 1. Achieve adequate isolation, and insert anterior restorations with “try-in” cement. 2. Verify marginal integrity. 3. Verify proximal contacts. 4. Obtain appropriate radiographs to confirm marginal fit. 5. Verify shade. 6. Verify incisal edge position (“E smile,” “repose,” “lateral smile view”) + photographs. 7. Verify phonetics. 8. Obtain patient approval (recommend written approval by patient). 9. Clean and prepare porcelain restorations per manufacturer’s instructions. 10. Isolate, clean, and prepare teeth (total etch technique). 11. Cement restorations in the same order as the try in, light cure, or self-cure.

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Fig. 10.18  Quality control: verifying proximal contact points

Fig. 10.19  Cementation materials

1 2. Adjust any occlusal interferences, smooth and polish. 13. Obtain appropriate radiographs to confirm complete removal of cement. 14. Final check, digital photos. Schedule post-cementation follow-up. The 14 steps listed above are in a specific order to eliminate any chance of error. For example, in step #4, if the marginal integrity is compromised, then there is no need to proceed unless a solution is in place (for example; if the proximal

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contacts are too tight—adjusting them may result in improved marginal integrity). If there is no solution to the lack of marginal integrity, then there is no need to move forward to step 5 as this becomes irrelevant. Nevertheless, once the restorations are confirmed (steps 1–7), it is extremely important to have the patient’s approval, verbally and most importantly in writing. Too many times a patient will go home and call back a few days later with concerns about how the restorations appear. Sometimes, these concerns can be easily corrected (contours and occlusion), but issues related to shade and position can be more challenging, such as remaking restorations that costs the dentist time and money. Having an approval in writing helps create patient ownership of the final results. Steps 9–14 outline the final delivery of the final restorations. The illustrations associated with steps 9–14 are examples of the procedures used by the author. It is recommended that no matter what products you use to cement all-porcelain restorations, instructions should be followed strictly as directed by the product. Restorations are cleaned, rinsed, and treated with a silane agent to improve the bond strength. Figures 10.20 and 10.21 illustrate this process as outlined in step 9. While the assistant is preparing the restorations (step 9), the dentist can begin step 10 by cleaning the preparations with plane fine pumice. Figures 10.22 and 10.23 illustrate the preparation of the teeth prior to cementation. When cementing restorations, it is important to place the restorations in the same order as in step 1 above. This ensures adequate seating and keeps the flow consistent during this step. Figures 10.24 and 10.25 illustrate the final cementation from placement to checking the occlusion. Step 13 assures that any remaining cement is removed by taking appropriate radiographs—see Fig. 10.26. Earlier in this chapter, quality control was discussed by using a reference from the provisional restorations to the final restorations. Upon

Fig. 10.20  Cementation: clean restorations after try in with Ivoclean

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Fig. 10.21  Cementation: prepare restorations after cleaning with Mono Bond Plus

Fig. 10.22  Cementation: steps 1 and 2—pumice and acid etch all preparations

delivery of the final restorations, the consistency in the quality control is evident by comparing the restorations intraorally to the working model. Figures 10.27 and 10.28 illustrate the consistency and precision of the restorations in relation to axial inclination, embrasure space, and proportions. This also confirms the skill level of the laboratory technician in creating restorations that not only look natural, but also fit beautifully and support good tissue health. These final restorations are fully illustrated in Figs. 10.29, 10.30, and 10.31, while Figs. 10.32 and 10.33

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Fig. 10.23  Cementation: steps 3 and 4—apply bonding material and light cure

Fig. 10.24  Cementation: steps 5–9—fill restorations with cement, insert restorations in the same order as the try in

provide side-by-­side comparisons of pre-op and post-op results. Figures  10.32 and 10.33 provide proof that from start to finish, the process of complete dentistry begins with a complete comprehensive examination. Using appropriate diagnostic records on a semi adjustable articulator, the treatment planning process becomes very predictable. This provides the patient with results that enhance the smile due to comfort and stability. It is very apparent in the post-op photos that the patient’s smile has become larger as a result of providing the best results.

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Fig. 10.25  Cementation: steps 10–15—final removal of cement, and final occlusal adjustments

Fig. 10.26  Cementation: final radiographs confirming all cement sealed and removed

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Fig. 10.27  Comparison of axial inclination and embrasures of restorations on the master models and intraorally

Fig. 10.28  Comparison of width to gingival margins of restorations on the master models and intraorally

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Fig. 10.29  Final delivery of restorations: retracted views

Fig. 10.30  Final delivery of restorations: smile views

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Fig. 10.31  Final delivery of restorations: repose, tip-down smile, and profile smile views

Fig. 10.32  Comparison of pre- and post-restorative digital photos (smile, E smile, tip down, and repose)

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Fig. 10.33  Comparison of pre- and post-restorative digital photos (left and right smile, profile smile)