Advanced Removable Partial Dentures [1 ed.] 9780867153514, 0867153512

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Advanced Removable Partial Dentures

James S. Brudvik, DDS, FACI' Professor Emeritus of Prosthodontics Unive rsity of\Vashingt on School of De ntistry Seattle, \ Vashington

Quintessence )lublishing Co, In c ClJicago, Berl in. Loudon , Tokyo, Paris, Barcelona, Sao Pau lo, ｾ ｴ ｯ ｓ ｃ ＨＩ ｗ Ｌ Pragu e, and \ Varsaw

l.ihntl)"of ｃ ｯｮ ｾ

Ｇｾ

C;t lalogi ng-in-P uh lic:; tlion D a t a

Bru(hik. [ nmes s. Advanced re movahlc part ial dentures I [anu-s S. Brudvik. p. e m. Includes index. IS BN O-1i67 15 -.3.'31 -2 (hard cov r-r} L f'urnal dentuu-s, Homovable. I. Tltk-. Il ) XL.\l : I . Deutu n-, Partial. Hemovnhlr-. WU .515 USfiSa I!/!)!)] Il Km'5 .R78 ＱＹＡ ｾ ｊ fil i .(i'lJ2- for this cast, b UI ca n you ln-lp me with a design?"' Thc preliminary impression a mi rcsultaut cast shou ld he of the same quality as the final imp ression as far as ext enslous, hard and son ussuc details, and integrity of the occlusal surface are concerne- d. Thi s Imp re ssion shollld 1)(' l'()I1sidered as a tri al impression for tile filial. Tray size is cvaluated. patient compliance with ill...tmct ions noted . ease of placement disco vered . and the patient's ability In sit still during Ihe set of the alginate evaluated. EWI)1 hillg that can he learned Fr om th is impression will aid the clinician in making an accurutc flnal im p ression. Sometime s Ill) stock tray will adequately 111 the mou th , ind k :iting tha t a custom t ray wtll have to he iucluded in preparation for the final Impression. Modtficatiou of tlu> stock tray wi th wax or co mpound lIlay hp m-cessary to allow the impwssion of horder tissues or high palatal vault. All tlll'SI' issues must be e"alilait'd whe n the prcltuunury impression is made so that the clinician « Ill concentra te 0 11 accuracv o f the ha rd tisS1U'S ill the final impression. Alginate can ht' expected to give ovcrextended borders due 10 its co nststency wln-n properly mixed. Und er JlO cir cumstances shoul d the powder-water ratio ｨＨ ｾ cbanged the mix. ltat he r; to reduce the viscosity the a moun t of algina to required 10 make a ' Iuality impression should be ca refully cstimated and only thai amo unt placed ill the tril)'. Alginate 1I111sl Ill:>placed into thr- critical a reas: rest seats , guid ing planes, soft tisSlit' unde rcu ts, etc. One ca nno t count on the mate rial llm\i llg 10 these a re as of its own accord . The mate rial call he placed

or

with the finger or inje-cted IIsing a syriuJ?:e. but ill 110 Instance should the trav Ill:' placed in the mouth unti l all critica l arr-as are wi ped wi th alginate, Borders should be filled IIsing a syri nJ?:e , A plastic 3.') ce Monojct syringe wn h 10 to 1.5 cc of ｡ｬｾ Ｎ nate will work well in mos t situations, The critical areas a re buccal 10 the tuberosit ies and the ret romyloh yold space, places where voids are ofte n found ill the complf'kl l impres sion . AnIJII I('r ad van tage ' If placing alginate in the 1I10u th before seating the tray is that Ie-ss man-rial (the total mix minus the 10 to 1.'5 ( 'I: ) 1J("t'(1 be place d in the tray. re sultin g in increased visibility for tray placement. \ \ l lt'lle vpr possible. th(> stock tray is modifk-d by adding wax or compo und to allow a minimum of 0.2.'5 inch of alginate around all cri tical structures . A C'()l1ln IOl I problem with alginate is ovt>rseati ng or tho tray, rpsllltillg in less th an the re-quire-d 0.2,'5 Inch of mute- ria] ove-r the' occ lusal sur faces . Stops can he placed in ｴｨ ｬ ｾ tray Ilsing hard \\,LX or de ntal co mpo und to restrid till' m·('TS(·;Itinr;. Unfortunately; the area of till' stop will often be distorted due to the minimal alginate present. The required occlus al spacing may he obtained hy placing the empty Iray ill the mouth. scaling it 10 CO IItact with the occlusal surfaces, and evaluating the relative l X)SI!i Oll of the handle to the lips whe-n the tray is lifted the 0.2.5 inch . 111 making the impression , the tray is seatedt o that lifted position and lu-kl in place unti l the imp n-ssion is set. \\1wll the imp ression is removed from the mou th. it must he rinsed and light ly dried. then inspected for h ';I TS and any cvidcncc of the material Im'aking Free from the rimlock or retentive holes. \\11e n using a rtmlock ｴ ｦｩｴ Ｉ ｾ excess alginate- should be cut from 1111' borders with a sha rp knife so that J

Advanced Remova ble Partial Dent ure s

the edge of the tray can be seen and the re tention of tile alginate verified. Alginate is clearly an abused impre ssion material, hut it is the material of choice fo r both preliminary and fina l impre ssions for the removable partial denture . Seldom is th e alginat e mixed fo r the manufactu rer's recomm ended time. Likewise , it is ofte n not allowed time /;J!" a comple te set befo re removal from the mouth. Many Inaccurate impress ions can he traced to the pati e nt's inuhility to remain motio nless d uring the sett ing phase. \Vhcn th e t ime in th e month has been alte red hy using ve ry co ld water or not mixing for t he usual flO seco nds , the patient is forced to re main mo tion less for lon ger than ne cessary. Since alginate docs not set all at once hut in scattered islands, any move ment hy clinician or pati e nt du ring the selling pe riod rUJl S the ris k of reorienting the partially set material and p roduc ing a d istorted imp ression. Ideally, the set shou ld begi n promptly afte r the tray is in its prope r pos itio n and any border molding has occurred. Algina te mixed with the proper mcasuru of rOOl n-te mpe rature (65°F to 70°F) water will allow roughly a minute for loading the tray and placing it in the mo uth be for e the se t hegins . Optimal gelation time shou ld be between :3 and 4 minutes using 68°F wat er. The pa tien t is instru cted to remain motionless during this time . The initial imp ression gives the clinician the op po rtun ity to test the patient's ab ility in th is regilrd to increase the prohabtltty that the fina l impressio n will he accurat e. Should the patien t move du ring the fina l imp ression, it must he remade and the pati e nt informed again of his or he r pa rt ill this procedure. If the mixing of the alginate is inc o mplete, a reduction of up to :5W7rJ in th e str ength of the ge l can be expected. On the 4

ot her ham!' alginate mixed beyo nd the manufacturer's sta ted tim e will have a redu ced gel stre ngth since t he fo rm ing gels will he broken. Mech anical mixing devices, including vacuum mixing, are w ore apt to provide consiste ncy and thereby accu racy, and sho uld be cons idered as essential instrumentation . H and mixing for the full minute requi red by most manufacturers is no t that e asily accomplished awl. as a result, the n lixing time is seldom fully utilizcd. Alginat e ad hesives mus t be cons idered essential for all final impressio ns, h ut since th ey are not ｬＧｩｌｾｹ to remove from the tray, they are not required for the d iagnostic impression. w hen a stock rimlock tray is used, howeve r, ca re must he taken to force the alginat e into the rimlock with the spatula when loading the tray. O nce this has be en doric, the algina te is not likely to pop free of the lock. Nevert heless , the im pression should he ca refu lly inspect ed befo re pouring so that if a separation has occurred, the set algina te can he r 10 nun will require an 18-gauge wire . At th ese dist an ces an d these gauges, th e wires will give ap p roximately

• Removable Parti al De nture Des ign Height of conto ur There will be no ..-------buccal clas p arm

\

ｾｪＺ［Ｑ

Ｍ

o.oto- ircn undercut

o c Fig 2-16 Lingual rete ntive wire clasp above lingual plate.

th e sallie amount of re tent ion aIHI re mai n below their proporttonalltmtt . \Vhile it may

he possible 10 place some wires into un der cuts > 0.15 inch and still have th em function wit hout dist ortion , t here is n o clinical evid e nce th at th ts increase in undercut

depth is of any value. The wire clasp can he used successfully on the lingual surface of must mandibular premolars, in conju ncti on with a di stal gu ide pla te tha t exte nds slightly beyond the distal facial line angle an d a mes ial rest , to provide n-tenfinu without any display of buccal metal. In th ese situations, th e clasp an n will be very short and must therefore be of 20-gauge or finer wire. The major connector must be a lingual or sublingual bar, at least in the area of th is clasp, so that the requirement for :l nun of space at th e superior margin of the bar is essential In the maxilla. the major connector is open ed to the lingual as a matter of cou rse whe neve r possible, so that finding a lingual surface for the wire retentive clasp an n is not norm ally a problem if

the tooth contours provide any retentive areas of 0.010 inch or greate r. Ther e is no need fix a buccal bracing arm in these situations. When the major connector cannot be opened for any reaso n, it is still possible to utilize only a lingual clasp arm if suffid ent too th height exists to permit th e wire to sit on the occlusal border of the lingual plate and enter the proper un dercut. The only disadvantage to this design is the sligh t ope ning of the major connect or beneath the clasp tip (Fig 2-lG). Unlike cast clasp arms that can be expected to break if th ey are deformed and the n recontoured more than a few tim es, wire clasps (especially th ose of high-gold alloys) will withstan d repeated rcadap tation withou t any change in their retentive properties. Since these clasps are mo re flexible , they have th e disadvantage of being far easier for th e patient to deform if theyarc used as han dles to remove the partial from the mouth. Patients must be warned tha t defor mation of a properly 19

Advanced Removable Partial Dentures

0.0 1()'-inch unde rcut

F ig 2·17 Short w ire I-ba r to distobuccal retentive are a.

placed wire clasp can only occur if the wire is loaded heyond its pro portional [i III it and that this call happen on ly if tho clasp is distorted by the patie nt. SOllie putieuts insist 011 hiting their partials to place rathe r than placing the m wi th the finge rs of both hands. Patients mu st he shown that they can U S(' the flanges of th e denture base as a purchase point for rf"lll m l llg the rk-ntun'. Somet imes the placement of a simulated Class \' cavity o n a denture toot h wil l gin" the pat ient a purchase po int to apply a dislodging force .

Inf"bulge Clasps Illfrallilige clasps have Imlg 11('(' I I advocated as all ultemattve to the wire ctrcmnfcrcr rtial clasp for Class I and II situa tions. They have been proposed as a more esthet ic alte rnative to the cast ci rcmufeu-ntlal clasp as well. These clasps call come ill a num ber of forms and can be eithe r cast or wrought. The most co mmonly used iufr abulge clasp has been the l-bar; wh ich is to he placed at the greatpst convexity of the tooth meslodistally ,LS seen From the h0 I17.o 11tal. \\llell combined with a proximal guide plate at the edentulous side of the prim e abu tment

20

and a rest at the othe r e nd of the occlusal surface. 110 b racing arm is required . This is becaus e the tootll cannot be displaced by the action or th e re tentive clasp an n. Depending 0 11 the contact of the gllide plate, stres s relief ca n be created wi th this syste m for the Class I situation. \\'ht'll til(' l-bnr clasp is made of a suit able length and gauge of wire, additional advan tages are possible. Since the wire is added to th.. casting hy so ldering afte r the frame h:LS ｨ ｾＧ Ｇ Ｑ finished and po lished , it is possible to plan ' the clasp arm n"'ry close to tilt> buccal exte nsion of the guide pla te (Fig 2-17). \\'itll this distal posit ioning. the clasp ur tu become s shorte r an d mus t therefore 1)(' of a highe r gauge 10 retain flexibility (normally a 20-gauge wire wtll be chosen ). T hl' guiding plane and plat e mu st exte nd fully to the line anglo, ami a positive rest O il th e opposite side of tlie abutment urust he used to provide rc-ciprocation if till" distally placed l -bar is 0 11 a te rm ilia] abutment . I r this I)pe of clasping is used o n the ant erio r abutment of a Class 111 partial dr-uture. th e need for precise recip rocation is not as grea t because the po ste rior abutment will restrict d ist al movem e nt o f th e partial.

• Rem ovab le Partial Den ture Des ign

Height of contour

ｾ ｦｉＮｾＺ［Ｌ｜ＷＧ Fig 2- 18 Tooth-bar clasp re la-

.... 0.0 1O-inch undercut Cast

W ire

t ionship.

Hei ght of contou r

is ld t for the e mbrasure clasp, fracture of the retent ive clasp arm can be expected . Th e ph sttc pattern uSl't1 tu wax the clasp has a c ross-sed ional urcasureuu-nt of approximatr-ly L") 11 1In; should any reduction be Ilcce ssary on the occlusal po rtio n of the clasp, all area of stress concent ration will occur ami fractu re call be expect ed afte r repe ate d flexure . Repair of a broke n chesP ann in the embrasure a rea is d ifficu lt ami cannot bo depe-nde-d OJ1. ClI iding pla nes are usually 1101 prepared on anterior teeth lx-causc n ·shap illg of th e proxima l surfaces alters the shape of the too th 10 the po int where esthetics is ('OIIl · promised. Occasionally, a minor j:!;uiding plane call he crea ted O il lingu al surface s whe-re gingival recession or crown lengt h. l:ning leaves the full unatonuc been extracted and initial healing has tukr-u place or, and this is often the p rp-

bonding age nts ca n he used to add a toot h to the metal fram ewo rk. Fracture s of major connecto rs can ｉ ｉＨ ｾ rcpaired by IIsing 800 fine solde r and tlu- rcstst ancc hrazillg device. O b viously, t he mandibular bar will be the eastcst majo r co nnect o r to weld. since it offers eilsy access ove r a limited d istan ce. vlaxlllarv majo r connecto r repairs are seldo m wo rth the effo rt. The need for a major connector repair results more ofte n fro m distort ion rat her tha n fro m outright fract ure of lite metal. Th e pat ient who d rops it part ial and then step s 0 11 it can expect it not to fit all that w ell [rom then on . In an e mergency situation. tl](· maj or connector call he Sq);l rated \\11 11 a th in disk at the point or t ilt' perceived bend . if bo th segme n ts fit t ilt, mou th in all acce pta ble manner, it is worth makin g till' pick-up imp ression and selldiug the case off to the laboratory for wplding. Beyo nd this. major connector repair is not practical.

Icrn-d way, as an Immediate replacement followed by the extraction. In ei ther caw, the l'xistin g framework must hi' c..rpable of snppo rting the addition. As discussed ea r-

Her;

011 1'

indication for a lingual plate is

wln-n the po tential for toot h loss exists. \\111'11 a lingu al plate is prese nt, tilt' best results a re ob tained by ､ ｲｩ ｬｩ ｬ ｾ Iwo sma ll holes ill the plate and solde ring a smallloop of wire, usually one o r M , Cr, .md Co, into the holes so that th e loop is internal to the replacement denture tooth (Fi g cS-6). This fonu or retention will he as stro ng as one that is part of a new pa rtial fnuncwork \ \1lt'1I110 lingual plate exists and the re is insufficien t adjoining re sin to retain the de ntu re tooth , a cas t additio n is indicated (F ig 8-7). As in the replacement of the broken embrasur e clasp. the cost o r a quality repair Illay ap proach th at of a new c..lstiu g. Again. and O il a tl'lIlpomry basis, the -1 -:\1ETA

98

Rep airs, Add itions , and Relines

Restorations Under Existing RPDs It i s Hot unco m mon for abutment tee-th to req uire some form of restoration du ring the life of the- partia l denture, The two- or th ree-surface alloy restoratio n tha t [raetures at the isthmus is difficult to place under an existing partial and maintain positivc co ntact with the rest. III t hese illstances, the tooth usually requires repre paration of the box form 10 wid en. or deepen. Of some combination of the two, to ensure t hat all adequate bulk or amalgam is presPll1. These re storat ion s may also he mad e in composite if th e cltnfcfun is (' 0 111fortahle with its lise in th e poste rior. Since the composi te filling call he lay(·n·1! into the cavity; the final co ntact with the rest or o the r COlllpolIl'n ls of the part ial c..m be mad ", aft er the R 'III O\ ,tl o r the r nblx-r da m and mat rix. Ligh t activation or tln- c:ompos tte is usually po ssible in a ｴ ｜Ｂ ｯ Ｍ ｳ ｴ ｡ ｾ ＨＧ pnx't-ss where the material is first adi\·alt'C.l with the partial in place . T h is will usually set the material sufflcie ntlv to allow n-mov't 11 o r the parti al d e nture wit ho u t d isto rting the res to ration. Additionallight C ll ri llg with IIre pa rtial o ut o f the mou th completes the re sto ration . For 11105(' situuttons in which a complete composite restorati on is not indicnt cd. a combiruu lou of alloy and composite can 1)(' used to support an occlusal rest. Afte r the additional mou th preparation, the alloy is packed in the usual manner am i then a dovetailed bo x in the are a of the rest is formed (Fig 8-8). Chem ically curing CO IIIposite is placed ill the box. and the partial is fully seated iu the mou th until completely cured. This combination of restorativ e ma terials will allow the creation of a positive res t

Composite

Amalgam

Fig 8·8 Composite and amalgam combination to retrofit rest.

seat contact . SO llie limn of mtcrofillcd re sin is Ind tcuted in these l"t' ll possible when wo rking 0 1] a stone replica of the C ro\\11, due to th(· probable fracturing of thin p mjt>e1iolls of stom-. It also a llows the maste r cast to 1)1' IIs('(1 as a mill ing ca st to provide a stable platform for m illing metal surfaces of ti lt' fixed l 1 )111ponents. This procedure will req uire d eci sion as to w llt' m lx-st 10 joi n ti lt' attach men ts to the framework is dependent O il m any factors am i t he w is no one correct way. It must he remembered. II00n 'n ' r, t hai in every ins t ance th e fruuuvuttachment relationship mu st be iden tica l fro m th e mo uth to the master east befo re the co nstructio n ca n co ntinue . Most Intmco roual attachments will he joined to the fn uncwork by solderi ng because spaee is like ly to he a cr itical factor. T he Ilt of the fram ewo rk must he rever Hied after the soldering; openn ion ill cvc ry lustnuco. O nly when the tooth/ frame relatio n mcctx the highest standards can other procedures he undertaken, it ', altered cast impressions allcl jaw relation records. The com pk-tton of the cas e . once the-se ste ps are d one . is rel ative ly stand ard as fa r as posltlonlng o f the denture teeth a m i ｜ ｜ ｾ ｬｸ ｩ ｮｧ Ｎ p n x:t 'ssin g. a nd finishing of the base are conccnn-rl. An are a of special cousldcratlon is ｴ ｨｴ ｾ p ro tection of the patrix conm-rtion when the amoun t of resin over or around this un-a is m in im al (less tha n 2 111111 o f tooth str uct ure o r base resin). In these instances . metal occl usal surfaces a re 10 he coustructr-d. usually ill ＡＩ ｬｸ ｾ IV gold . a nd added to the denture teeth to ensure that suhse'l ue llt wear wtll not brea k th roll/-;ll to t he p atnx. At inse rtion of the intracoronal at tachmcnt partial den ture, any undercuts to the path o f fusert ton/re m oval wil l [ruvu to be carefully idl'lIti fled aIHI rccont ourcd to fnlly scat ti ll' part ial. Since the path of inse rt ion " i ll he so precise, the finished partlal mus t neve r he forced to place on initial seating until all possible un de-rcuts in re sin have lx-en ide ntified and adjusted, The soft tissues uf the mouth occlusal to areas of slight undercut Illay -J1:l

gllilli ng planes nn ･｡ｳ

ｬｩ ｬｾ

;lJld.

4i . 4S Illic n lj.,fTO" \'P p rqmTatio ll of "astillgs am i, 47, lkf vs bonded resincontours, ·I IJ-."')(l w as ·np ,111l! sprniu g,lH, ,I i'll' Bomh '(l n-sin oontours ｾ ｵｩ ､ ｩ ｬ ｧ

plane-s f'x , ·19 rr-st st·"ts for; -19. ·19 f

Bml'illg a rlJl. I6-17 , 17 f ｈ ｮ ｾ ｬ Ｎ ｉ ｉ ｬＩ［ ｬ ｡ｴ ｡ ｬ strap . 10, IOf in c lass II BPI), 2Hf

Hurl(·ws

1) 1)' Foil.

fnr ,.tI(l", Il l\'-

N agt', 123

c ('..a.sl H'uMn'able partia l l lt' u illn' ( HP O), conversion of ('\isling 10 pro\i sio na l re -si n BPI).

119---12.1 . 12()f o b H sn n ·p)in g, .18 Diast cmas , ill ｈＮｐ ｄｾ Ｌ 8.5 Double r-mhrasnrc clasp, 16, 161' 1) llp licatio ll ｡ ｧ｡ｲｾ for, 67 flask for; 6 7 liquid-powder ratio for ｮｾｦｬ｣ ﾭ tory cast, 67

E Embras ure clusp ill Class \I HI'\), 2S( 2S-2}) re-pair 01; 97, 97f subt ractive 1ll00 1t!J preparation for, 4.'5, 4fif

Endodontic cousultatiou prt-prosthc-tic, 6 Ex t racorun..rl pre cis ion attach ment (s),14.1-1.31 alt ered eas t fo r Class 1 or Class II, ]41) Ceka Hevax , 144--14!), 14,')[ EKA ove n lplltll w matrix, ] 471' 111t-

FUlld ional fit of frame 10 rk-utun- It't>j1J. , 6--77 o f fr.lI IM' to nuturnl tl't 'l h, 77 n·t rufitting of Il'"" Is ill. 77 mtation of fram.'\mrk in . ,6-77 ｾｴｮﾷｳＮ｜

rehefiu,

regislra ti" lllTJah-rials for. 79---1;U.

sof for HP J) upp•.>M-d ｾ Ｎ l'()mpld" (k '1lhm', MJ--t)l verfical d im. ' nSK)l1 o f oc ...·lns i(MI

IlK'll t tooth, 15S

1t·11K'll of. l5-i .M·i-t" l'ilig fo r implant silld

,6

in, S if, 8 1--82

attachment , 15, . l.:i' f ｉ ｘ ｾ ｩｬ

G

ｬＩ Ｑｬ

for. I ,) (j

K

pusl,' rior ex te nsion of 01'"

l)(",llIHI. 1.55, I,).')f posh'rior support of Class I 111'1), 154 , L'5.'5f as rt-tentive abunnout, lSi

( ; ui(l" platt'o\ us minor connectors, 12 fo r positivp rests , 9, ｾｊ ｦ

C;,Jid illg planes for bonded un-ta] contours. 47, 41'; ·12f ill c la,. 23--Z.'5. 2-tf. 25f ill sn h tmd in' lI KJllth pn"pararion. -11. -11 f, -1Z, -1Zf. -16

H 11i1l1.!;....l lIlajorO)lllK't"tOf)l. 10, - 110 do uble cas ting coustr uction of. lOS. 109f fr ontal view nf, Illi . ｛Ｈｾ Ｇｩ ｦ I,illg" (Iesign for. Wi indicntio!lS for, lilil prohli'Il IS with, IOH- l l 0 rr-st preparatiolls li,l'. 1Oil- l 09 W'JI( '('f{'(l lahia l phil., ill. 107, 1081"

l-har clasp, 20f. 20--21 ill Clasp II RPD. 3 1 ch\.I. II 1Il'1'li lla. 32 ill CUs s I HI' D , 2(" tI_Jllt-ba r rt'laliollship with, 21.

2Jf I-ha l' \\;1"\'" ehsp

cla-p

r{" -

placement. H·I--!).'), 95f

clasp urtns for. 12:J- 12·j l -bar \li re c h\ps ill , 12"3

matr-rials for. 123 prt' p'lratioll for. 121 Im plant-partial illkrh n ' . " IIl-

st n ldion of, 1.51i--157 Implallts ill c lass I ;Uld c h ...ｾ I I HPD s.

1.5.1--I.'i':l ahullllc n i CIll\\1ISOtl sill,.,-tt.. ＱＺ［Ｇｾ ahllt mclll for. 154, 1.54f

162

I ｾｬ ｨｯｲ

｡ｴ＼ＬｲＮ

Ｇ

construction o f fra lll, '_

work '

st ud-type attachments Oil , I,'> i Ch,,\ III and 1\ ' situa tio ns. 1,').3--1.59

hloekoHI ill. b')f. 6.'>--67. tiM eastiui-: ill ,

,n

ill

design lrall sf"r from master 10 l1·frad '"Y cast. 6.') dt-sigll Irallsfl or in. 64--fi.5

Impn ·ssiulIs _ ｾ Final im pn'ss io ll; l'i