CLINICAL AND RESEARCH REPORTS Tretment Strtegies in the Cse of Advnced Attchment Loss Prt 2: Extrction of Criticl Teeth nd Dentl Restortions on Movle Autments Andres Rühling In ptients with dvnced one loss, it is desirle to use tretment strtegy tht conserves criticl teeth, to void complictions during prosthetic restortion. Prt 1 discussed tretment options for teeth with horizontl one loss down to the picl third of the root, verticl one defects with poor defect morphology, furctions with lrge defect height nd comined periodontl nd endodontic inflmmtion. If tretment strtegy is followed in which criticl teeth re extrcted in cses of dvnced ttchment loss, seting prosthetic restortion on periodontlly compromised utments cnnot e voided. In ddition to periodontl tretment of the remining dentition, this strtegy should focus on periodontl risk ssessment nd the voidnce of iomechnicl nd technicl complictions when seting dentl restortions. A cse presenttion of Generlized Aggressive Periodontitis followed for 11 yers demonstrtes the implementtion of periodontl tretment nd prosthetic restortion. Key words: tretment strtegy, periodontitis, one loss, dentl restortions, tooth moility RISK ASSESSMENT BEFORE PROSTHETIC RESTORATION Decisions regrding tretment cnnot e tken solely on the sis of evidence-sed dentistry, ut must lso respect the ptient s wishes, nd tke into ccount current lws nd guidelines, s well s the dentl prctitioner s experience. The ptient s finncil circumstnces nd the periodontl nd prosthetic risks should lso e considered. P rt 1 showed tht periodontl tretment enles the conservtion of criticl teeth with dvnced ttchment loss for mny yers without pro g re s- sive one loss. This pro c e d u re is not, however, wit nd see strtegy of oservtion fter periodontl surg e ry. It is rther n ctive mintennce t h e r p y, with the im of recognizing nd tre t i n g remining periodontl pockets or re c u rring locl inflmmtion t n erly stge, s well s of cont rolling other risks such s endodontic complictions nd furction cries. If, in the cse of dvnced generlized ttchment loss, criticl teeth cnnot e treted ut need to e extrcted, this is significnt for the plnning of susequent pro s- thetic restortion; it rises the question of the prognosis of the periodontlly treted ut possily l redy moile remining utments, nd ultimtely the question of the life expectncy of the intended dentl restortion. According to Lng nd Tonetti (1997) six ptient relted risk fctors for periodontl disese were presented in risk digrmm (Fig. 1): inflmmtory condition (leeding on proing) frequency of remining periodontl pockets history of tooth loss ge-relted ttchment loss genetic nd/or systemic risk fctors lifestyle (e.g. smoking). Fig. 1 shows three different risk levels. The trnsition from low to intermedite risk occurs t 9% leeding on proing, with four remining pockets, four teeth lost, 0.5% one loss fctor nd occsionl smoking, wheres the trnsition to high risk is chrcterized y 25% leeding on proing, 213
Bleeding on proing In conclusion, decisive prognostic fctors for the long-term success of dentl restortions on periodontlly treted utments include: Smoking Syst./gen, risk remining pockets Tooth loss ensuring sence of inflmmtion y ctive mintennce therpy tking genetic, systemic or personl risk fctors into ccount voiding iomechnicl nd technicl complictions. It should e noted tht, tooth moility is not fctor in the risk digrmm. Bone loss/ Age Fig. 1 Risk digrm (ccording to Lng nd Tonetti, 2003) of 33-yer-old femle ptient with 3% leeding on proing, three pockets 5 mm nd five missing teeth. There re no systemic disorders nd the ptient is nonsmoker. The ge-relted one resorption fctor is 3.0. The clcultion is sed on the premolr or molr t which the one resorption is frthest dvnced. In the cse of this ptient, loclized one resorption extending to the root tip (100%) ws oserved, which t n ge of 33 yers, denotes fctor of 3.0. The overll risk of disese progression is clssed s intermedite, s three prmeters re low risk, one prmeter is intermedite risk nd only one is in the high-risk sector. eight remining pockets, eight teeth lost, 1.0% one loss fctor nd fewer thn 20 cigrettes smoked per dy. Risk of disese is considered to e low s long s not more thn one prmeter is t the intermedite level. Intermedite risk exists when two prmeters re situted t the intermedite level nd high risk occurs when t lest two prmeters re t high level. In ddition, prosthetic risks must lso e tken into ccount (Nymn nd Lindhe, 1979; Nymn nd Ericsson, 1982; Lndolt nd Lng, 1988; Hämmerle, 1994). Nymn nd Ericsson concluded tht the size of the remining ligment re on the utment teeth ws not s vitl for long term success of fixed ridge restortions, ut tht endodontic, iomechnicl nd technicl prolems cn led to the loss of fixed ridge restortions. These include root nd sustructure frctures s well s frctures of solder res nd retention loss of cemented utment crowns. TOOTH MOBILITY AND PERIODONTAL TRAU- MA ON PROSTHETIC ABUTMENTS A loose tooth is something tht cuses the ptient g ret unesiness, nd when perceptily incre s e d moility persists, despite successful periodontl t retment, the dentist is fced with the question of whether the tooth cn e mintined on longt e rm sis s prosthetic utment. Lng (1982), nd Hrrel (2003) hve discussed the significnce of moility nd the consequences this hs for prosthetic restortion on the sis of studies concluded minly in the 1970s y Ericson nd Lindhe, 1977; Lindhe nd Nymn, 1997; Lindhe nd Svnerg, 1974; Svnerg, 1974. A c c o rding to these studies, incresed moility cn e seen s logicl consequence of dvnced one loss nd the ltered lever effect in the cro w n - root reltionship. The extent of moility is dditionlly determined y the inflmmtory condition of the periodontl tissue, nd cn e intensified y the effect of n occlusl periodontl trum. In u n t reted periodontitis, ttchment loss cn e p ro g ressively ccelerted y periodontl trum. The primry cuse of the oserved ttchment loss is periodontl inflmmtion, wheres periodontl trum cn e re g rded merely s co-fctor. It is remrkle tht, fter successful periodontl tre t- ment, periodontl trum cn led to incre s e d m o i l i t y, ut does not necessrily result in further ttchment loss in the cse of inflmmtion-free periodontl conditions (Ericsson nd Lindhe, 1977; Lindhe nd Svnerg, 1974; Svnerg, 1974). On the sis of their results (Nymn nd Ericsson, 1982; Nymn nd Lindhe, 1979) fixed restortions were seted in periodontlly treted ptients 214
Fig. 2 Teeth with dvnced one resorption nd incresed moility cn e retined over mny yers provided tht inflmmtion cn e prevented y periodontl tretment. () At teeth 12, 11 nd 21, one resorption down to picl third hd occurred. () The cuse of the grde III moility cn e seen not only in the height loss of the supporting one, ut lso in periodontl trum resulting from premture contcts on the existing ridge restortion in the mndile. Rdiologiclly no further cliniclly relevnt one resorption could e oserved 13 yers lter (c). c without resulting in progressive one loss, despite the fct tht the conditions postulted y Ante were not fulfilled (Ante, 1926). In histologicl cse re p o rt it ws demonstrted tht the clmp nchoring of prosthesis to moile utment with dvnced one loss ut inflmmtion free tissues led to periodontl trum nd n increse in moility, ut tht histologiclly detectle remodelling procedures hd occurred in the ligment re without further loss of ttchment (Rühling nd Plgmnn, 2003). In this instnce, incresed moility coupled with lck of inflmmtion in the 215
periodontl tissue cn lso e interpreted s physiologicl dpttion under high functionl lodi n g. A study y König et l. (2002) demonstrted tht it is possile to retin 90% of teeth with third degree moility over 8 yers in function. This is illustrted in ptient in which one loss hd occurre d t teeth down to the picl third (Fig. 2).Tretment consisted of preventing inflmmtion, eliminting premture contcts nd splinting with retiner wire. Despite the degree III moility no further cliniclly relevnt one loss ws detected fter 13 yers (Fig. 2c). In conclusion, the role of periodontl trum nd incresed moility should not e overestimted with regrd to its prognostic vlue. In the cse of prosthetic utments with incresed moility, periodontl trum should e treted nd/or voided s fr s is possile. The min issue, however, is the prevention of inflmmtion. Attention should e focused on the incresed moility, s this cn led to technicl nd iomechnicl complictions fter the seting of prosthetic restortions. BIOMECHANICAL AND TECHNICAL COMPLI- CATIONS IN PROSTHETIC RESTORATION Regrding the mnufcture nd seting of dentl restortions on moile utments, certin fctors should e tken into ccount y the dentist nd dentl technicin, to void iomechnicl nd technicl prolems. Retention Loss nd Root Frcture The im of utment preprtion is to crete secure form of retention with smll preprtion ngles, to prevent the loss of retention of cemented utment crowns (Hämmerle, 1994). Good conditions cn exist in cses of dvnced one loss when the prepred utments re very long. Suprgingivl positioning of the crown mrgins is helpful, s this voids plcing overcontured mrgins of the restortion close to mrginl gingiv nd fcilittes impression-tking. Owing to the l e n g t h of the utments, however, proper shoulder preprtion is often not possile without endngering their vitlity. The sme pplies when, for esthetic resons, the preprtion mrgins must e positioned sugingivlly. A further compliction is tht, in dvnced periodontitis, tooth migrtion my hve occurred, which mkes the preprtion of common pth of insertion impossile. The root frcture is compliction tht cn led to the loss of dentl restortions (Hämmerle, 1994; Hämmerle et l, 2000) (Figs 3 nd ). According to results otined y Nymn nd Lindhe (1979), 2.4% of the utment teeth frctured, nd in the cse of Lndolt nd Lng (1988), 3% of the vitl nd 35% of the endodonticlly treted utments were ffected y frctures. This is confirmed y further reserch results, ccording to which endodonticlly treted teeth frctured more frequently, prticulrly in the cse of cntilever utments (Rndow nd Glntz, 1986). In the cse of exggerte teeth-clening technique nd regulr professionl root plning, suprgingivl preprtion cn result in tooth sustnce loss t the exposed cervicl re, which my in turn led to n utment frcture (Figs 3c nd 3d). Endodonticlly treted utments re usully reinforced with posts or post core constructions. To void root frctures, the focus should e not only on the selection of suitle post system, ut lso on the conservtion of nturl tooth sustnce. The preprtion width of the root cnl nd the dimension of the root cnl post must e selected in such wy tht the structurl strength of the tooth is not unnecessrily wekened. When prepring the root stump for definitive crown, ferrule preprtion y 2 to 3 mm should e pplied, so tht the risk of frcture is reduced considerly (Glntz nd Nymn, 1982; Mezzomo et l, 2003; Zhi-Yue nd Xu-Xing, 2003). Prolems Occurring during Impression-tking nd Frmework Mnufcture Becuse of incresed moility, undesirle movement of the utment cn hppen when using rigid mterils during impression-tking. For the sme resons, difficulties cn lso occur during the removl of the impression, prticulrly in pronounced undercuts of the tpering of the root elow suprgingivl preprtion limit, s well s not enough locking out of the wide open interproximl spces. The ccidentl extrction of tooth rrely occurs, s tooth with helthy remining ligments, even with ttchment loss of two thirds of the root length, 216
c d Fig. 3 Technicl nd iomechnicl complictions threten the long-term success of tretment. () In 1985 the ridge utment of 17 ws root-mputted nd ridge seted; () 18 yers lter no progressive loss of ttechment ws oserved, longitudinl frcture of the utment 15 hd occurred. In nother ptient, (c) removle restortion with suprgingivl mrgins ws seted in 1985. The telescope rdiogrph from 2003 shows tht fter 18 yers of ctive mintennce therpy with rushing technique nd regulr scling, tooth sustnce loss to the exposed tooth necks hd occurred, which hd in turn led to the trnsverse frcture of utment 45 nd the mesil root 46. still possesses sufficient stility despite incres e d m o il i t y, provided tht undercuts re cre f u l l y locked out. For dditionl sfety, n crylic imp ression try, e.g. stle replic of pre f r i c t- ed try cn e used, which cn, if necessry, should cut prt. When removing impressions of very long prepred teeth, the dentl technicin should e informed so tht prepred roots do not rek off during the mking of the plster model. It is etter to cut the individul impression try prt efore removing the impression. If occlusl splints do not fit perfectly when mounting the models in the rticultor, it is possile tht, not only while mking the impression ut lso during ite registrtion, deflections nd hence inccurcies occur ecuse of incresed utment moility. When seting rigid, locked crowns or ridge sustructures on utments with different degrees of moility, high degree of tension cn result in the sustructures s result of norml occlusl function, leding to n incresed risk of ftigue frcture in the metl sustructure. For this reson, stle sustructures mnufctured with distortionresistnt lloy nd voiding soldering prticulrly furnce soldering re recommended. Tooth migrtion mens it is not lwys possile to chieve common pth of insertion (Fig. 4). To n extent, this prolem cn e compensted ecuse of the moility of the utments themselves. Fig 4 shows tht only very rief deflection of the nterior teeth is required to insert the sustructure (Fig. 4c). At the moment in which the crown mrgins 217
c d Fig. 4 () Tooth moility s result of dvnced periodontitis mde it impossile to prepre common pth of insertion. On mnufcturing the sustructure () the non-xil position of the prepred utments cn e seen. (c) A rief deflection of the nteriors is required to set the sustructure. (d) At the moment in which the crown mrgins rech the preprtion limit, the utments in the lveolr ridge re once gin stress free. rech the preprtion limit, the utments emedded in the lveolr ridge re once gin free from tension (Fig. 4d). During the mnufcture of telescopic restortions on moile utments, considertion should e given to the dhesive force of conus crowns; if too gret, this cn led not only to periodontl trum resulting in further increse in moility, ut lso in frcture of the tooth root (Figs 3c nd d) if the suprconstruction cn only e removed y the ptient y pplying lrge mount of forc e. Prticulr cre is required to void this prolem. Whether the outer prt of the telescope will ecome detched from the inner prt is not solely dependent on defined dhesive force, ut lso on the strength of the utment itself. For this reson, in the cse of utments with incresed moility, it my e good lterntive solution to im for fixed restortions with primry splinting of the utment teeth (Bölle-Müller, 1994; Nymn nd Lng, 1994). 218
Fig. 5 In the cse of 33-yer-old ptient with generlized ggressive periodontitis, periodontl tretment with susequent prosthetic restortion ws performed in 1992. () The nterior gingiv ws more or less unremrkle. (, c) Posteriorly, severe inflmmtion with loclized exuding pus ws oserved. c CASE PRESENTATION: PERIODONTAL TREAT- MENT AND PROSTHETIC RESTORATION IN ADVANCED GENERALIZED AGGRESSIVE PERIODONTITIS Cse History This 33-yer-old womn ws referred to us y her dentist in 1992. She hs een suffering from recurring pocket scesses since 1990. She ws non-smoker nd hd no systemic diseses. Dignosis The ptient s dentition ws in good condition in t e rms of conservtive nd prosthetic dentistry nd testified to good orl hygiene. The nterior gingiv ws unremrkle (Fig. 5), ut the molrs showed, severe inflmmtion with loclized exsudtion (Figs. 5 nd c) nd proing depths of 6 to 12 mm with furction involvement, detectle y proing. Rdiologicl Exmintion The rdiogrphs of the mxill nd mndile showed no severe one loss nteriorly. Advnced one loss with deep, verticl defects nd mrg i n- l/picl confluent rdiolucencies s well s osteolytic grnuloms were oserved t teeth 25 28, 34 nd 44 48. Tooth 13 showed profound cries. Incomplete root-cnl fillings were seen in teeth 16, 35 nd 44 (Figs. 6, 7). A vitlity check of tooth 34 reveled wek positive rection (Fig. 10). Dignosis Generlized Aggressive Periodontitis, cries on tooth 13 nd suspected endo-perio lesion on tooth 34 were dignosed. 219
Fig. 6 The rdiogrph from 1992 shows severe dvnced one resorption in ll four qudrnts, with deep verticl defects, mrginl/picl confluent lightening nd notly lrge osteolytic centres on teeth 25, 27 nd 28. Tretment Strtegy The tretment gol ws to extrct hopeless teeth, crry out periodontl tretment with root resections on the furction involved molrs nd if possile, set fixed temporry prosthetic restortion consisting of metl-reinforced ridges. Becuse of the remrkly lrge osteolytic grnuloms, iopsy w s perf o rmed to rule out Lngerhns Cell H i s t i o c y t osis. Therpy The initil tretment session in 1992 comprised the immedite extrction nd/or resection of more l e s s teeth or single roots. A smple of grnultion tissue ws tken t tooth 26 for pthohistologicl sure the sence of exmintion to Lngerhns Cell Histiocytosis. The result ws negtive. In the mxill, resection of the distouccl root nd revision of the root cnl filling of tooth 16, root cnl fillings of 13 (Figs. 7 nd ), rdectomy of the mesiouccl nd distouccl roots of 26 with root cnl filling in the pltl root (Figs. 8 nd ) nd extrction of 18, 25, 27 nd 28 were performed. In the mndile, teeth 44, 45 nd 48 were extrcted, the mesil root of 46 nd the distl root of 47 resected nd the remining roots of 46 nd 47 treted endodonticlly (Figs. 9). In the 3rd qudrnt root cnl filling ws crried out on 35 with closed root deridement (Figs. 10 nd ). Susequently metl-re i n f o rced, long-term tempor ry restortion ws seted from 24 to 26, with the pltl root of 26 s ridge utment, nd ridge from 43 to 46/47 with the distl root of 46 nd the mesil root of 47 s ridge utments. Prosthetic Restortion The temporry ridges were replced with permnent ones two yers fter the strt of tre t m e n t y the ptient s regulr dentist (Fig. 11). The ridge in the fourth qudrnt ws connected y n ttchment distlly of tooth 43. Mintennce Tretment (1992 2004) The ptient hs een receiving mintennce tre t- ment for 11 yers. The verge plque index is 11%; the proing depth is generlly 2 3 mm nd, t tooth 35, up to 5 mm without leeding on pro - i n g. The rdiogrph of the ridge utment 46/47 showed no further cliniclly relevnt one loss in 1995, ut good osseous regenrtion mesilly 220
Fig. 7 () The 1992 rdiogrph shows furction involvement of tooth 16 with n incomplete endodontic filling nd picl lightening on ll three roots. () After correction of the root cnl fillings the distouccl root ws root-mputted, therey conserving the crown. Fig. 8 The 1992 rdiogrph shows() the extent of the extremely dvnced ggressive periodontitis in the second qudrnt. Only tooth 14 nd the pltl root of 16 re not ffected y complete ttchment loss. ()The uccl roots of tooth 16 were root-mputted nd teeth 15, 17 nd 18 extrcted. of tooth 46 nd distlly of tooth 47 (see Fig. 9c). At tooth 34 connective tissue-like heling, ut no progressive one resorption, ws oserved in the distl one defect (Fig. 10). There ws no disese progression in the rdiogrphs in 1996, 1999 nd 2003 (Fig. 12)compred with 1994 (Fig. 6). Compliction (2003) The rdiogrph imge from 2003 (Fig. 12) showed peripicl lesion of endodontic orgin on the rdectomied utments 46/47 nd verticl defect distlly of tooth 47. Epicrisis In 1992 the 33-yer-old ptient presented for tre t- ment of generlized ggressive periodontitis. R d i o l o g i c l l y, severe dvnced one re s o r p t i o n with remrkly lrge, mrginl/picl confluent osteolytic grnuloms ws oserved. A Lngerh n s Cell Histiocytosis ws dignosticlly ruled out. The primry im of tretment ws to rrest the progression of the periodontitis nd to tret the ptient prostheticlly in the interim with metl-reinforced ridges. Owing to the ggressive chrcter of the periodontitis, solely therpeutic considertions with regrd to the possiilities of periodontl tret- 221
Fig. 9 () The 1992 rdiogrph shows deep verticl defects lso ffecting the pex, prticulrly mesilly of tooth 46 nd distlly of tooth 47 (see Fig. 6). () Teeth 44, 45 nd 48 were extrcted nd the mesil root of 46 nd the distl root of 47 mputted. (c) Rdiologicl exmintion five yers lter showed no indiction of n ggressive progression of the disese, ut rther dense osseous stiliztion t 46/47. c Fig. 10 () In the 3rd qudrnt only strictly loclized defect t tooth 34 could e oserved. The rdiogrph shows tht mesilly of 34 rdiolucent one wll structure is still present, while distlly the ttchment loss hs reched the pex. A comined periodontlendodontic lesion ws suspected. After endodontic tretment, the picl inflmmtion ws first llowed to hel nd the remining pocket treted with root deridement. () A rdiologicl exmintion 12 yers lter lter reveled no signs of osseous regenertion ut no progressive one loss despite of the ggressive type of disese. ment were mde; specultive discussion regrding the definitive prosthetic restortion in prticulr concerning the long-term prognosis of implnts ws deliertely voided. Teeth tht could not e mintined were immeditely extrcted nd strtegiclly importnt molrs rdectomied or endodonticlly treted. Since the initil tretment resulted in compliction-free heling, ntiiotics were not required. The periodontl tretment ws crried out without regenertive pproch s none of the verticl one crters nd furction involved molrs wrrnted the use of regenertive methods. Furctions on the molrs were successfully eliminted y root re s e c t i o n s. 222
c d Fig. 11 Two yers fter strting tretment, the metl-reinforced provisionl restortions were replced y permnent ridges. Figs. nd c show the ridge from tooth 24 to the pltl root 26. In the mndile the criticl tooth 35 ws treted to conserve the ridge from 35 to 37 ( nd d). In the upper jw, the crown of 16 ws conserved fter rdectomy ( nd c). In the mndile seting of ridge of tooth 43 on the distl root of 46 nd the mesil root of 47. The ridge ws divided y precision ttchment distlly of tooth 43 ( nd d). A comined periodontl/endodontic lesion ws suspected in the isolted defect distlly of tooth 34 lthough the tooth showed wekly sensitive rection. Since the ridge from 35 to 37 ws to e conserved, 34 ws now of strtegic importnce. The preopertive proing depth ws 12 mm. Endodontic tretment nd root deridement to depth of only 6 mm to llow heling of the periodontitis piclis ws performed. The rdiogrph showed neither one-dense filling nor ny signs of progressive one resorption 12 yers postopertively, ut the tooth ws cliniclly unremrkle nd the proing depth ws 4 5 mm without leeding on proing. The ptient decided in fvor of the replcement of the metl-re i n f o rced temporry ridges y definitive ridges from 24 to 26 nd 43 to 46/47, with the option of n implnt in the fourth qudrnt t lter dte. Owing to the incresed risk of root frcture, the rdectomied utments were supported y thin root posts nd dhesively supported, nd the ridge ws divided y stress rking ttchment distlly of 43 to counterct possile technicl complictions. A postopertive rdiologicl exmintion of utment 46/47 fter 5 yers showed no signs of progressive one resorption, ut did show osseous regenertion mesilly nd distlly. Eleven yers postopertively (2003) compliction ecme evident t 46/47. Rdiologiclly exmintion reveled peripicl lesions nd one defect distlly of root 47. This is suspected to e n endodontic origin or n in- 223
Fig. 12 The rdiogrphs imge from 2003 shows tht, 11 yers fter tretment, there ws no signs of progressive periodontitis. However, peripikl lesion t the distl root 46 nd the mesil root 47 s well s distl one defect hd occurred. Since n endodontic origin or n incomplete longitudinl root frcture is suspected, the extrction of the utment cn not e voided. complete frcture of the roots. A loclized pro i n g depth of 7 mm ws mesure d. The primry im of tretment nmely to rrest the progression of the ggressive periodontitis ws chieved; the loss of the ridge in the fourth qudrnt, however, cn not e voided. Should the suspected dignosis of root frcture of this ridge utment e confirmed, this would represent typicl iomechnicl compliction, s descried. After extrction, osseous implnts in the regions 44, 45 nd 46 re plnned s n option with good prognosis. The risk profile of the ptient c c o rding to Lng nd Tonetti (see Fig. 1) shows tht t the eginning of mintennce therpy (1992), the pro p o rtion of leeding on proing ws only 3%, with three remining pockets ( 5 mm) nd five missing teeth, ut the ge-relted one resorption fctor ws very high (3.0). The ptient hd reported no systemic diseses nd ws non-smoker. This represents n intermedite risk for p ro g ressive ttchment loss, since three fctors re in the low-risk nd one fctor (one loss) in the highrisk segment. Becuse of the ggressive nture of the disese, discussion out implnt re s t o r t i o n hs een voided t the outset of tretment. Even if the risk profile hs not ltered significntly in the course of the susequent 11 yers, prognosis cn e descried s good on the sis of the overll positive results of the tretment to dte, so tht there re no contrindictions to implnt re s t o r t i o n s. 224
CONCLUSIONS When it is necessry to set dentl restortions of ptients with dvnced ttchment loss, the min focus of tretment fter the periodontl tretment of the prosthetic utments is in preventing inflmmtion y ctive mintennce therpy nd the voidnce of iomechnicl nd technicl complictions. An individul risk nlysis ccording to Lng nd Tonetti cn help in the ssessment of the periodontologicl prognosis. The prognostic vlue of incresed tooth moility nd the role of periodontl trum should not e overestimted. A periodontl trum cn increse moility y occlusion or the nchoring of prosthetic restortions, ut given inflmmtion-free periodontl tissues, does not utomticlly led to pro g ressive ttchment loss. With re g rd to the mnufcture of dentl re s t o r t i o n s, whether from the point of view of the dentist or dentl technicin, the nture of the individul sitution must e tken into ccount to void typicl complictions such s root frctures, sustru c t u re frcture s, f r c t u re of solder res nd retention loss of cemented utment crowns. In the cse of ptients with g g ressive periodontitis, the success of the periodontl tretment should first e ensured to fulfil the criteri for n implnt re s t o r t i o n. REFERENCES Ante, I.C.H.: The fundmentl principles of utments. Mich Stte Dent Soc Bull 1926; 8: 14-23. Bölle-Müller, K., Hürzeler, M. B., Schönenerger, J.R., Röhrich, J.: Festsitzender Zhnerstz im prodontl strk reduzierten Geiß. Prodontologie 1994; 5: 21-35. Ericsson, I., Lindhe, J.: Lck of effect of trum from occlusion on the recurrence of experimentl periodontitis. J Clin Periodontol 1977; 4: 115-127. Glntz, P.O., Nymn, S.: Technicl nd iophysicl spects of fixed prtil dentures for ptients with reduced periodontl support. J Prosthet Dent 1982; 47: 47-51. Hämmerle, C.H.: Success nd filure of fixed ridgework. Periodontol 2000 1994; 4: 41-51. Hämmerle, C.H., Ungerer, M.C., Fntoni, P.C., Brägger, U., Burgin, W., Lng, N.P.: Long-term nlysis of iologic nd technicl spects of fixed prtil dentures with cntilevers. Int J Prosthodont 2000; 13: 409-415. Hrrel, S.K.: Occlusl forces s risk fctor for periodontl disese. Periodontol 2000 2003; 32: 111-117. König, J., Plgmnn, H.C., Rühling, A., Kocher, T.: Tooth loss nd pocket proing depths in complint periodontlly treted ptients: retrospective nlysis. J Clin Periodontol 2002; 29: 1092-1100. Lndolt, A., Lng, N.P.: Erfolg und Misserfolg ei Extensionsrücken. Schweiz Montsschr Zhnmed 1988; 98: 2 3 9-2 4 4. Lng, N.P.: Ws heisst funktionelle Rekonstruktion im prodontl reduzierten Geiss? Act Prodontol 1982; 2: 4 1-7 6. Lng, N.P., Tonetti, M.S.: Prodontle Risikonlyse ls Bestndteil der Betreuung nch ktiver Prodontltherpie. Prodontologie 2003; 14: 357-365. Lindhe, J., Nymn, S.: The role of occlusion in periodontl disese nd the iologicl rtionle for splinting in tretment of periodontitis. Orl Sci Rev 1997; 10: 11-43. Lindhe, J., Svnerg, G.: Influence of trum from occlusion on progression of experimentl periodontitis in the egle dog. J Clin Periodontol 1974; 1: 3-14. Mezzomo, E., Mss, F., Lier, S.D.: Frcture resistnce of teeth restored with two different post-nd-core designs cemented with two different cements: n in vitro study. Prt I. Quintessence Int 2003; 34: 301-306. Nymn, S., Ericsson, I.: The cpcity of reduced periodontl tissues to support fixed ridgework. J Clin Periodontol 1982; 9: 409-414. Nymn, S.R., Lng, N.P.: Tooth moility nd the iologicl rtionle for splinting teeth. Periodontol 2000 1994; 4: 1 5-2 2. Nymn, S., Lindhe, J.: A longitudinl study of comined periodontl nd prosthetic tretment of ptients with dvnced periodontl disese. J Periodontol 1979; 50: 1 6 3-1 6 9. Rndow, K., Glntz, P.O.: On cntilever loding of vitl nd non-vitl teeth. An experimentl clinicl study. Act Odontol Scnd 1986; 44: 271-277. Rndow, K., Glntz, P.O., Zöger, B.: Technicl filures nd some relted clinicl complictions in extensive fixed prosthodontics. An epidemiologicl study of long-term clinicl qulity. Act Odontol Scnd 1986; 44: 241-255. Rühling, A., Plgmnn, H.C.: Der üerelstete prothetische Pfeiler nch PAR-Behndlung. Trum oder physiologische Adpttion? Ein klinisch-histologischer Fllericht. Prodontologie 2003; 14: 389-395. Svnerg, G.: Influence of trum from occlusion on the periodontium of dogs with norml or inflmed gingive. Odontol Revy 1974; 25: 165-178. Zhi-Yue, L., Yu-Xing, Z.: Effects of post-core design nd ferrule on frcture resistnce of endodonticlly treted mxillry centrl incisors. J Prosthet Dent 2003; 89: 368-373. Reprint requests: Senior Physicin, Dr. med. dent. Andres Rühling Deprtment of Periodontology Clinic for Conservtive Dentistry nd Periodontology Universitätsklinikum Schleswig-Holstein, Cmpus Kiel Arnold-Heller-Strße 16, D-24105 Kiel, Germny e-mil: ruehling@konspr.uni-kiel.de 225