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CLINICAL AND RESEARCH REPORTS

RISK ASSESSMENT BEFORE PROSTHETICRESTORATION

Decisions regarding treatment cannot be takensolely on the basis of evidence-based dentistry, butmust also respect the patient’s wishes, and take in-to account current laws and guidelines, as well asthe dental practitioner’s experience. The patient’sfinancial circumstances and the periodontal andprosthetic risks should also be considered.P a rt 1 showed that periodontal treatment enablesthe conservation of critical teeth with advancedattachment loss for many years without pro g re s-sive bone loss. This pro c e d u re is not, however, a“wait and see” strategy of observation after peri-odontal surg e ry. It is rather an active maintenancet h e r a p y, with the aim of recognizing and tre a t i n gremaining periodontal pockets or re c u rring localinflammation at an early stage, as well as of con-t rolling other risks such as endodontic complica-tions and furcation caries. If, in the case of ad-vanced generalized attachment loss, critical teethcannot be treated but need to be extracted, this is

significant for the planning of subsequent pro s-thetic restoration; it raises the question of the pro-gnosis of the periodontally treated – but possiblya l ready mobile – remaining abutments, and ulti-mately the question of the life expectancy of theintended dental restoration. According to Langand Tonetti (1997) six patient related risk factorsfor periodontal disease were presented in a riskdiagramm (Fig. 1):

• inflammatory condition (bleeding on probing)• frequency of remaining periodontal pockets• history of tooth loss• age-related attachment loss• genetic and/or systemic risk factors• lifestyle (e.g. smoking).

Fig. 1 shows three different risk levels. The transi-tion from low to intermediate risk occurs at 9%bleeding on probing, with four remaining pockets,four teeth lost, a 0.5% bone loss factor and occa-sional smoking, whereas the transition to high riskis characterized by 25% bleeding on probing,

Treatment Strategies in the Case of AdvancedAttachment LossPart 2: Extraction of Critical Teeth and DentalRestorations on Movable Abutments

Andreas Rühling

In patients with advanced bone loss, it is desirable to use a treatment strategy that conserves crit-ical teeth, to avoid complications during prosthetic restoration. Part 1 discussed treatment op-tions for teeth with horizontal bone loss down to the apical third of the root, vertical bone de-fects with poor defect morphology, furcations with a large defect height and combined peri-odontal and endodontic inflammation. If a treatment strategy is followed in which critical teethare extracted in cases of advanced attachment loss, seating a prosthetic restoration on peri-odontally compromised abutments cannot be avoided. In addition to periodontal treatment of theremaining dentition, this strategy should focus on periodontal risk assessment and the avoidanceof biomechanical and technical complications when seating dental restorations. A case presen-tation of Generalized Aggressive Periodontitis followed for 11 years demonstrates the imple-mentation of periodontal treatment and prosthetic restoration.

Key words: treatment strategy, periodontitis, bone loss, dental restorations, tooth mobility

eight remaining pockets, eight teeth lost, a 1.0%bone loss factor and fewer than 20 cigarettessmoked per day. Risk of disease is considered tobe low as long as not more than one parameter isat the intermediate level. Intermediate risk existswhen two parameters are situated at the interme-diate level and high risk occurs when at least twoparameters are at high level.In addition, prosthetic risks must also be taken in-to account (Nyman and Lindhe, 1979; Nymanand Ericsson, 1982; Landolt and Lang, 1988;Hämmerle, 1994). Nyman and Ericsson conclud-ed that the size of the remaining ligament area onthe abutment teeth was not as vital for long termsuccess of fixed bridge restorations, but that en-dodontic, biomechanical and technical problemscan lead to the loss of fixed bridge restorations.These include root and substructure fractures aswell as fractures of solder areas and retention lossof cemented abutment crowns.

In conclusion, decisive prognostic factors for thelong-term success of dental restorations on peri-odontally treated abutments include:

• ensuring absence of inflammation by activemaintenance therapy

• taking genetic, systemic or personal risk factorsinto account

• avoiding biomechanical and technical compli-cations.

It should be noted that, tooth mobility is not a fac-tor in the risk diagramm.

TOOTH MOBILITY AND PERIODONTAL TRAU-MA ON PROSTHETIC ABUTMENTS

A “loose tooth” is something that causes the patientg reat uneasiness, and when perceptibly incre a s e dmobility persists, despite successful periodontalt reatment, the dentist is faced with the question ofwhether the tooth can be maintained on a long-t e rm basis as a prosthetic abutment.Lang (1982), and Harrel (2003) have discussedthe significance of mobility and the consequencesthis has for prosthetic restoration on the basis ofstudies concluded mainly in the 1970s by Ericsonand Lindhe, 1977; Lindhe and Nyman, 1997;Lindhe and Svanberg, 1974; Svanberg, 1974.A c c o rding to these studies, increased mobility canbe seen as a logical consequence of advancedbone loss and the altered lever effect in the cro w n -root relationship. The extent of mobility is addition-ally determined by the inflammatory condition ofthe periodontal tissue, and can be intensified bythe effect of an occlusal periodontal trauma.In u n t reated periodontitis, attachment loss can bep ro g ressively accelerated by periodontal trauma.The primary cause of the observed attachment lossis periodontal inflammation, whereas periodontaltrauma can be re g a rded merely as a co-factor. It isremarkable that, after successful periodontal tre a t-ment, periodontal trauma can lead to incre a s e dm o b i l i t y, but does not necessarily result in further at-tachment loss in the case of inflammation-free peri-odontal conditions (Ericsson and Lindhe, 1977;Lindhe and Svanberg, 1974; Svanberg, 1974).On the basis of their results (Nyman and Ericsson,1982; Nyman and Lindhe, 1979) fixed restora-tions were seated in periodontally treated patients

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Fig. 1 Risk diagram (according to Lang and Tonetti,2003) of a 33-year-old female patient with 3% bleedingon probing, three pockets � 5 mm and five missing teeth.There are no systemic disorders and the patient is a non-smoker. The age-related bone resorption factor is 3.0.The calculation is based on the premolar or molar atwhich the bone resorption is farthest advanced. In the ca-se of this patient, localized bone resorption extending tothe root tip (100%) was observed, which at an age of33 years, denotes a factor of 3.0. The overall risk of di-sease progression is classed as intermediate, as three pa-rameters are low risk, one parameter is intermediate riskand only one is in the high-risk sector.

Bleeding on probing

Bone loss/ Age

Tooth loss

remaining pockets

Syst./gen,risk

Smoking

without resulting in progressive bone loss, despitethe fact that the conditions postulated by Antewere not fulfilled (Ante, 1926). In a histologicalcase re p o rt it was demonstrated that the clampa nchoring of a prosthesis to a mobile abutmentwith advanced bone loss but inflammation free tis-

sues led to periodontal trauma and an increase inmobility, but that histologically detectable remod-elling procedures had occurred in the ligamentarea without further loss of attachment (Rühlingand Plagmann, 2003). In this instance, increasedmobility coupled with lack of inflammation in the

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Fig. 2 Teeth with advanced bo-ne resorption and increased mobili-ty can be retained over manyyears provided that inflammationcan be prevented by periodontaltreatment. (a) At teeth 12, 11 and21, bone resorption down to api-cal third had occurred. (b) Thecause of the grade III mobility canbe seen not only in the height lossof the supporting bone, but also inperiodontal trauma resulting frompremature contacts on the existingbridge restoration in the mandible.Radiologically no further clinicallyrelevant bone resorption could beobserved 13 years later (c).

b

a

c

periodontal tissue can also be interpreted as phys-iological adaptation under high functional load-i n g .A study by König et al. (2002) demonstrated thatit is possible to retain 90% of teeth with third de-gree mobility over 8 years in function. This is illus-trated in a patient in which bone loss had occurre dat teeth down to the apical third (Fig. 2a).Treatmentconsisted of preventing inflammation, eliminatingpremature contacts and splinting with a retainerwire. Despite the degree III mobility no further clin-ically relevant bone loss was detected after 13years (Fig. 2c). In conclusion, the role of periodontal trauma andincreased mobility should not be overestimatedwith regard to its prognostic value. In the case ofprosthetic abutments with increased mobility, peri-odontal trauma should be treated and/or avoidedas far as is possible. The main issue, however, isthe prevention of inflammation. Attention should befocused on the increased mobility, as this can leadto technical and biomechanical complications af-ter the seating of prosthetic restorations.

BIOMECHANICAL AND TECHNICAL COMPLI-CATIONS IN PROSTHETIC RESTORATION

Regarding the manufacture and seating of dentalrestorations on mobile abutments, certain factorsshould be taken into account by the dentist anddental technician, to avoid biomechanical andtechnical problems.

Retention Loss and Root Fracture

The aim of abutment preparation is to create a se-cure form of retention with small preparation an-gles, to prevent the loss of retention of cementedabutment crowns (Hämmerle, 1994). Good con-ditions can exist in cases of advanced bone losswhen the prepared abutments are very long.Supragingival positioning of the crown margins ishelpful, as this avoids placing overcontured mar-gins of the restoration close to marginal gingivaand facilitates impression-taking. Owing to thel e n g t h of the abutments, however, a proper shoul-der preparation is often not possible without en-dangering their vitality. The same applies when,for aesthetic reasons, the preparation margins mustbe positioned subgingivally. A further complication

is that, in advanced periodontitis, tooth migrationmay have occurred, which makes the preparationof a common path of insertion impossible. The root fracture is a complication that can lead tothe loss of dental restorations (Hämmerle, 1994;Hämmerle et al, 2000) (Figs 3a and b).According to results obtained by Nyman andLindhe (1979), 2.4% of the abutment teeth frac-tured, and in the case of Landolt and Lang(1988), 3% of the vital and 35% of the endodon-tically treated abutments were affected by frac-tures. This is confirmed by further research results,according to which endodontically treated teethfractured more frequently, particularly in the caseof cantilever abutments (Randow and Glantz,1986). In the case of a exaggerate teeth-cleaningtechnique and regular professional root planing,supragingival preparation can result in tooth sub-stance loss at the exposed cervical area, whichmay in turn lead to an abutment fracture (Figs 3cand 3d).Endodontically treated abutments are usually rein-forced with posts or post core constructions. Toavoid root fractures, the focus should be not onlyon the selection of a suitable post system, but alsoon the conservation of natural tooth substance.The preparation width of the root canal and the di-mension of the root canal post must be selected insuch a way that the structural strength of the toothis not unnecessarily weakened. When preparingthe root stump for a definitive crown, a ferrulepreparation by 2 to 3 mm should be applied, sothat the risk of fracture is reduced considerably(Glantz and Nyman, 1982; Mezzomo et al,2003; Zhi-Yue and Xu-Xing, 2003).

Problems Occurring during Impression-takingand Framework Manufacture

Because of increased mobility, undesirable move-ment of the abutment can happen when usingrigid materials during impression-taking. For thesame reasons, difficulties can also occur duringthe removal of the impression, particularly in pro-nounced undercuts of the tapering of the root be-low a supragingival preparation limit, as well asnot enough blocking out of the wide open inter-proximal spaces.The accidental extraction of a tooth rarely occurs,as a tooth with healthy remaining ligaments, evenwith attachment loss of two thirds of the root length,

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still possesses sufficient stability despite increas e dm o b il i t y, provided that undercuts are care f u l l yblocked out. For additional safety, an acrylic im-p ression tray, e.g. a stable replica of a pre f a b r i c a t-ed tray can be used, which can, if necessary, shouldcut apart. When removing impressions of verylong prepared teeth, the dental technician shouldbe informed so that prepared roots do not breakoff during the making of the plaster model. It is bet-ter to cut the individual impression tray apart be-fore removing the impression. If occlusal splints donot fit perfectly when mounting the models in thearticulator, it is possible that, not only while mak-ing the impression but also during bite registration,deflections – and hence inaccuracies – occur be-cause of increased abutment mobility.

When seating rigid, blocked crowns or bridgesubstructures on abutments with different degreesof mobility, a high degree of tension can result inthe substructures as a result of normal occlusalfunction, leading to an increased risk of fatiguefracture in the metal substructure. For this reason,stable substructures manufactured with a distortion-resistant alloy and avoiding soldering – particular-ly furnace soldering – are recommended.Tooth migration means it is not always possible toachieve a common path of insertion (Fig. 4). To anextent, this problem can be compensated becauseof the mobility of the abutments themselves. Fig 4bshows that only a very brief deflection of the ante-rior teeth is required to insert the substructure (Fig.4c). At the moment in which the crown margins

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Fig. 3 Technical and biomechanical complications threaten the long-term success of treatment. (a) In 1985 the bridgeabutment of 17 was root-amputated and a bridge seated; (b) 18 years later no progressive loss of attechment was ob-served, a longitudinal fracture of the abutment 15 had occurred. In another patient, (c) a removable restoration with su-pragingival margins was seated in 1985. The telescope radiograph from 2003 shows that after 18 years of activemaintenance therapy with a brushing technique and regular scaling, tooth substance loss to the exposed tooth necks hadoccurred, which had in turn led to the transverse fracture of abutment 45 and the mesial root 46.

a b

c d

reach the preparation limit, the abutments embed-ded in the alveolar ridge are once again free fromtension (Fig. 4d).During the manufacture of telescopic restorationson mobile abutments, consideration should be giv-en to the adhesive force of conus crowns; if toogreat, this can lead not only to a periodontal trau-ma resulting in a further increase in mobility, but al-so in fracture of the tooth root (Figs 3c and d) if thesupraconstruction can only be removed by the pa-tient by applying a large amount of forc e .Particular care is required to avoid this problem.Whether the outer part of the telescope will be-come detached from the inner part is not solely de-pendent on a defined adhesive force, but also on

the strength of the abutment itself. For this reason,in the case of abutments with increased mobility, itmay be a good alternative solution to aim for fixedrestorations with primary splinting of the abutmentteeth (Bölle-Müller, 1994; Nyman and Lang,1994).

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Fig. 4 (a) Tooth mobility as a result of advanced periodontitis made it impossible to prepare a common path of insertion.On manufacturing the substructure (b) the non-axial position of the prepared abutments can be seen. (c) A brief deflection ofthe anteriors is required to seat the substructure. (d) At the moment in which the crown margins reach the preparation limit,the abutments in the alveolar ridge are once again stress free.

a b

c d

CASE PRESENTATION: PERIODONTAL TREAT-MENT AND PROSTHETIC RESTORATION IN ADVANCED GENERALIZED AGGRESSIVE PERIODONTITIS

Case History

This 33-year-old woman was referred to us by herdentist in 1992. She has been suffering from re-curring pocket abscesses since 1990. She was anon-smoker and had no systemic diseases.

Diagnosis

The patient’s dentition was in good condition int e rms of conservative and prosthetic dentistry andtestified to good oral hygiene. The anterior gingi-va was unremarkable (Fig. 5a), but the molarsshowed, severe inflammation with localized exsu-dation (Figs. 5b and c) and probing depths of

6 to 12 mm with furcation involvement, detectableby probing.

Radiological Examination

The radiographs of the maxilla and mandibleshowed no severe bone loss anteriorly. Advancedbone loss with deep, vertical defects and marg i n-al/apical confluent radiolucencies as well as oste-olytic granulomas were observed at teeth 25–28,34 and 44–48. Tooth 13 showed profound caries.Incomplete root-canal fillings were seen in teeth 16,35 and 44 (Figs. 6, 7a). A vitality check of tooth34 revealed a weak positive reaction (Fig. 10a).

Diagnosis

Generalized Aggressive Periodontitis, caries ontooth 13 and a suspected endo-perio lesion ontooth 34 were diagnosed.

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Fig. 5 In the case of a 33-year-old patient with gene-ralized aggressive periodontitis, periodontal treatmentwith subsequent prosthetic restoration was performed in1992. (a) The anterior gingiva was more or less unre-markable. (b, c) Posteriorly, severe inflammation with lo-calized exuding pus was observed.

a b

c

Treatment Strategy

The treatment goal was to extract hopeless teeth,carry out periodontal treatment with root resectionson the furcation involved molars and if possible,seat a fixed temporary prosthetic restoration con-sisting of metal-reinforced bridges. Because of theremarkably large osteolytic granulomas, a biopsyw as perf o rmed to rule out Langerhans CellH i s t i o c y t osis.

Therapy

The initial treatment session in 1992 comprised theimmediate extraction and/or resection of more l e s steeth or single roots. A sample of granulation tissuewas taken at tooth 26 for pathohistological asurethe absence of examination to Langerhans CellHistiocytosis. The result was negative.In the maxilla, resection of the distobuccal rootand revision of the root canal filling of tooth 16,root canal fillings of 13 (Figs. 7a and b), radec-tomy of the mesiobuccal and distobuccal roots of26 with a root canal filling in the palatal root(Figs. 8a and b) and extraction of 18, 25, 27and 28 were performed.In the mandible, teeth 44, 45 and 48 were ex-tracted, the mesial root of 46 and the distal root

of 47 resected and the remaining roots of 46 and47 treated endodontically (Figs. 9). In the 3rdquadrant a root canal filling was carried out on 35with closed root debridement (Figs. 10a and b).Subsequently a metal-re i n f o rced, long-term tempo-r a ry restoration was seated from 24 to 26, with thepalatal root of 26 as a bridge abutment, and abridge from 43 to 46/47 with the distal root of46 and the mesial root of 47 as bridge abutments.

Prosthetic Restoration

The temporary bridges were replaced with per-manent ones two years after the start of tre a t m e n tby the patient’s regular dentist (Fig. 11). The bridgein the fourth quadrant was connected by an at-tachment distally of tooth 43.

Maintenance Treatment (1992–2004)

The patient has been receiving maintenance tre a t-ment for 11 years. The average plaque index is11%; the probing depth is generally 2–3 mm and,at tooth 35, up to 5 mm without bleeding on pro b-i n g .The radiograph of the bridge abutment 46/47showed no further clinically relevant bone loss in1995, but a good osseous regenaration mesially

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Fig. 6 The radiograph from 1992 shows severe advanced bone resorption in all four quadrants, with deep verticaldefects, marginal/apical confluent lightening and notably large osteolytic centres on teeth 25, 27 and 28.

of tooth 46 and distally of tooth 47 (see Fig. 9c).At tooth 34 a connective tissue-like healing, but noprogressive bone resorption, was observed in thedistal bone defect (Fig. 10). There was no diseaseprogression in the radiographs in 1996, 1999and 2003 (Fig. 12)compared with 1994 (Fig. 6).

Complication (2003)

The radiograph image from 2003 (Fig. 12) showed aperiapical lesion of endodontic orgin on the radec-tomied abutments 46/47 and a vertical defect distallyof tooth 47.

Epicrisis

In 1992 the 33-year-old patient presented for tre a t-ment of a generalized aggressive periodontitis.R a d i o l o g i c a l l y, severe advanced bone re s o r p t i o nwith remarkably large, marginal/apical confluentosteolytic granulomas was observed. A Langerh a n sCell Histiocytosis was diagnostically ruled out.The primary aim of treatment was to arrest the pro-gression of the periodontitis and to treat the patientprosthetically in the interim with metal-reinforcedbridges. Owing to the aggressive character of theperiodontitis, solely therapeutic considerationswith regard to the possibilities of periodontal treat-

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Fig. 7 (a) The 1992 radiograph shows furcation involvement of tooth 16 with an incomplete endodontic filling andapical lightening on all three roots. (b) After correction of the root canal fillings the distobuccal root was root-amputated,thereby conserving the crown.

a b

Fig. 8 The 1992 radiograph shows(a) the extent of the extremely advanced aggressive periodontitis in the secondquadrant. Only tooth 14 and the palatal root of 16 are not affected by complete attachment loss. (b)The buccal roots oftooth 16 were root-amputated and teeth 15, 17 and 18 extracted.

a b

ment were made; a speculative discussion re-garding the definitive prosthetic restoration – inparticular concerning the long-term prognosis ofimplants – was deliberately avoided.Teeth that could not be maintained were immedi-ately extracted and strategically important molarsradectomied or endodontically treated. Since the

initial treatment resulted in complication-free heal-ing, antibiotics were not required. The periodontaltreatment was carried out without a regenerativeapproach as none of the vertical bone craters andfurcation involved molars warranted the use of re-generative methods. Furcations on the molars weresuccessfully eliminated by root re s e c t i o n s .

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Fig. 9 (a) The 1992 radiograph shows deep verticaldefects also affecting the apex, particularly mesially oftooth 46 and distally of tooth 47 (see Fig. 6). (b) Teeth44, 45 and 48 were extracted and the mesial root of46 and the distal root of 47 amputated. (c) Radiologi-cal examination five years later showed no indication ofan aggressive progression of the disease, but rather adense osseous stabilization at 46/47.

a b

c

Fig. 10 (a) In the 3rd quadrant only a strictly locali-zed defect at tooth 34 could be observed. The radio-graph shows that mesially of 34 a radiolucent bonewall structure is still present, while distally the attachmentloss has reached the apex. A combined periodontal-endodontic lesion was suspected. After endodontic treat-ment, the apical inflammation was first allowed to healand the remaining pocket treated with root debridement.(b) A radiological examination 12 years later later reve-aled no signs of osseous regeneration but no progres-sive bone loss despite of the aggressive type of disease.

a b

A combined periodontal/endodontic lesion wassuspected in the isolated defect distally of tooth 34although the tooth showed a weakly sensitive re-action. Since the bridge from 35 to 37 was to beconserved, 34 was now of strategic importance.The preoperative probing depth was 12 mm.Endodontic treatment and a root debridement to adepth of only 6 mm to allow healing of the peri-odontitis apicalis was performed. The radiographshowed neither bone-dense filling nor any signs ofprogressive bone resorption 12 years postopera-tively, but the tooth was clinically unremarkableand the probing depth was 4–5 mm withoutbleeding on probing.The patient decided in favor of the replacement ofthe metal-re i n f o rced temporary bridges by defini-

tive bridges from 24 to 26 and 43 to 46/47, withthe option of an implant in the fourth quadrant at alater date. Owing to the increased risk of root frac-ture, the radectomied abutments were supportedby thin root posts and adhesively supported, andthe bridge was divided by a stress braking at-tachment distally of 43 to counteract possible tech-nical complications. A postoperative radiologicalexamination of abutment 46/47 after 5 yearsshowed no signs of progressive bone resorption,but did show osseous regeneration mesially anddistally. Eleven years postoperatively (2003) acomplication became evident at 46/47.Radiologically examination revealed periapical le-sions and a bone defect distally of root 47. This issuspected to be an endodontic origin or an in-

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Fig. 11 Two years after starting treatment, the metal-reinforced provisional restorations were replaced by permanentbridges. Figs.a and c show the bridge from tooth 24 to the palatal root 26. In the mandible the critical tooth 35 was trea-ted to conserve the bridge from 35 to 37 (a and d). In the upper jaw, the crown of 16 was conserved after radectomy (band c). In the mandible seating of a bridge of tooth 43 on the distal root of 46 and the mesial root of 47. The bridge wasdivided by a precision attachment distally of tooth 43 (b and d).

a b

c d

complete fracture of the roots. A localized pro b i n gdepth of 7 mm was measure d .The primary aim of treatment – namely to arrest theprogression of the aggressive periodontitis – wasachieved; the loss of the bridge in the fourth quad-rant, however, can not be avoided. Should thesuspected diagnosis of a root fracture of thisbridge abutment be confirmed, this would repre-sent a typical biomechanical complication, as de-scribed. After extraction, osseous implants in theregions 44, 45 and 46 are planned as an optionwith good prognosis. The risk profile of the patienta c c o rding to Lang and Tonetti (see Fig. 1) showsthat at the beginning of maintenance therapy(1992), the pro p o rtion of bleeding on probing was

only 3%, with three remaining pockets (� 5 mm)and five missing teeth, but the age-related bone re-sorption factor was very high (3.0). The patienthad reported no systemic diseases and was anon-smoker. This represents an intermediate risk forp ro g ressive attachment loss, since three factors arein the low-risk and one factor (bone loss) in the high-risk segment. Because of the aggressive nature ofthe disease, discussion about implant re s t o r a t i o nhas been avoided at the outset of treatment. Even ifthe risk profile has not altered significantly in thecourse of the subsequent 11 years, prognosis canbe described as good on the basis of the overallpositive results of the treatment to date, so that therea re no contraindications to implant re s t o r a t i o n s .

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Fig. 12 The radiographs image from 2003 shows that, 11 years after treatment, there was no signs of progressive peri-odontitis. However, a periapikal lesion at the distal root 46 and the mesial root 47 as well as a distal bone defect had oc-curred. Since an endodontic origin or an incomplete longitudinal root fracture is suspected, the extraction of the abutmentcan not be avoided.

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Rühling, A., Plagmann, H.C.: Der überbelastete prothetischePfeiler nach PAR-Behandlung. Trauma oder physiologischeAdaptation? Ein klinisch-histologischer Fallbericht. Parodontologie 2003; 14: 389-395.

Svanberg, G.: Influence of trauma from occlusion on the peri-odontium of dogs with normal or inflamed gingivae.Odontol Revy 1974; 25: 165-178.

Zhi-Yue, L., Yu-Xing, Z.: Effects of post-core design and ferruleon fracture resistance of endodontically treated maxillarycentral incisors. J Prosthet Dent 2003; 89: 368-373.

Reprint requests:Senior Physician, Dr. med. dent. Andreas RühlingDepartment of PeriodontologyClinic for Conservative Dentistry and PeriodontologyUniversitätsklinikum Schleswig-Holstein, Campus KielArnold-Heller-Straße 16, D-24105 Kiel, Germanye-mail: ruehling@konspar.uni-kiel.de

225Perio 2004; Vol 1, Issue 3: 213–225

Rühling · Treatment Straegies in Advanced Attachment Loss. Part II – Extraction of critical teeth and dental restorations

CONCLUSIONS

When it is necessary to seat dental restorations of patients with advanced attachment loss, the mainfocus of treatment – after the periodontal treatment of the prosthetic abutments – is in preventing in-flammation by active maintenance therapy and the avoidance of biomechanical and technical com-plications. An individual risk analysis according to Lang and Tonetti can help in the assessment of theperiodontological prognosis. The prognostic value of increased tooth mobility and the role of peri-odontal trauma should not be overestimated. A periodontal trauma can increase mobility by occlusionor the anchoring of prosthetic restorations, but given inflammation-free periodontal tissues, does not au-tomatically lead to pro g ressive attachment loss. With re g a rd to the manufacture of dental re s t o r a t i o n s ,whether from the point of view of the dentist or dental technician, the nature of the individual situationmust be taken into account to avoid typical complications such as root fractures, substru c t u re fracture s ,f r a c t u re of solder areas and retention loss of cemented abutment crowns. In the case of patients witha g g ressive periodontitis, the success of the periodontal treatment should first be ensured to fulfil the cri-teria for an implant re s t o r a t i o n .