Long-term survival of cast-gold inlays in a specialized dental practice.

At a dental office in Münster, Germany, the majority of gold inlays incorporated between July 1969 and August 1999 (n=2,071) in 531 patients were checked with reference to the dental records and assessed retrospectively to determine their longevity. One hundred seventy-five gold inlays were rated as failures (no longer in situ); 10 abutment teeth were extracted. The 20-year Kaplan-Meier survival rate for restoration-bearing teeth was 98.9%, and the 25-year rate for all gold inlays 73.4% (+/- 4.0%; 95% confidence interval respectively in brackets). Gold inlays inserted in maxillary teeth had significantly better probabilities of survival after this period than those inserted in lower teeth (P=0.0002). Based on the number of surfaces involved, 52.0% (+/- 45.3) of one-surface inlays, 64.3 (+/- 7.5) of two-surface inlays, 75.8% (+/- 7.6) of three-surface inlays, and 84.8% (+/- 5.4) of inlays with more than three surfaces were still in situ after 25 years.

Preparation of autogenous bone grafts in two different bone mills.

The purpose of this study was to evaluate the performance of two bone mills (R Quetin Bone Mill and Micro Knochenmühle, Aesculap) for the grinding of autogenous bone (intraoral, cortical) according to the following criteria: (1) loss of bone during the grinding process, (2) particle size of the chips, (3) variability in chip size, (4) technical handling, and (5) cost-benefit ratio. The amount of material loss was determined by harvesting 30 bone cores from the mandibular symphysis of a pig. Each specimen was weighed before and after the grinding procedure on scales with an accuracy of 0.1 mg. The size and variability of the bone particles were determined histomorphometrically. Twenty-seven bone specimens from different patients were analyzed. Eight were ground with the Aesculap and 12 with the Quetin mill. Seven specimens harvested with a Brånemark implant bur served as controls. A histologic section was prepared from each specimen, and 10 bone particles per section were subjected to histomorphometric analysis. The Quetin mill was superior in all points to the Aesculap mill for the requirements of a periodontal practice.

Long-term clinical results of galvano-ceramic and glass-ceramic individual crowns.

STATEMENT OF PROBLEM: Alternatives to metal-ceramic restorations should possess clinical durability before being recommended to the dentist. Longitudinal clinical studies are required for evaluation so innovative types of restorations can meet the expectations of dentists and patients. PURPOSE: This study compared the performance of galvano-ceramic restorations (Auvo Galvano Crown [ACG]) and glass-ceramic individual crowns (Dicor) based on longitudinal clinical trials. MATERIAL AND METHODS: A total of 769 galvano-ceramic single crowns (AGC) in 322 patients and 173 glass-ceramic individual crowns (Dicor) in 88 patients were reviewed for 8 years and a maximum of 11 years, respectively, after cementation. Risk of fracture was determined with use of a survival analysis (Kaplan and Meier). RESULTS: Partial ceramic cracking was observed at the time of the last recording of data in 11 galvano-ceramic crowns, 8 of the units remained in place. Two crowns became dislodged and 1 tooth exhibited a fractured root, despite an intact crown. One restoration was removed because of hypersensitivity and 1 with partial ceramic fracture. Forty-two of the glass-ceramic crowns were completely fractured. After a comparable 7 years under risk, 96.5% (+/-3.4; 95% confidence interval) of the galvano-ceramic premolar and molar crowns and 92% (+/- 8.5) of crowns placed on incisors and canines crowns were intact. The corresponding data for the glass-ceramic restorations were only 70% (+/- 10.6) in posterior and 82.7% (+/- 8. 1) in anterior quadrants. CONCLUSION: Long-term results of electroformed individual crown restorations were superior to glass-ceramic restorations.

Distal movement of premolars to provide posterior abutments for missing molars.

In 24 patients with missing molar teeth in the upper and/or in the lower jaw, 32 premolars were distalized. The mean orthodontic distalizing distance was 9.4 mm (SD 2.6). After distalization all these teeth served as posterior abutments for fixed restorations. The investigation period ranged between 2.5 to 14.1 years, average 9.6 years (SD 3.2). The clinical examination criteria were sensitivity, mobility, probing depth, sulcus bleeding index; the radiologic criteria were root resorption (lateral and apical) marginal bone level and axial position. None of the 32 premolar abutments were lost during investigation period. All the teeth maintained their vitality. The measured probing depths and sulcus bleeding indices were low. Of the teeth tested 40.6% revealed localized lateral root resorption on the pressure side; the average postorthodontic depth of root resorption was 0.7 mm (SD 0.3), and the length 2.3 mm (SD 0.6). The follow-up examination revealed a partial repair of the lateral root lesions. The extent of apical root resorption amounted to 0.9 mm (SD 1.1). The marginal bone level showed a bone loss of 0.5 mm mesially and 0.2 mm distally. The findings confirm that the distalized premolar functioning as a posterior bridge abutment represents a prognostically favorable alternative to an implant.

[Teamwork in the dental practice with special regard to periodontology]. / Teamarbeit in der zahnärztlichen Praxis unter besonderer Berücksichtigung der Parodontologie.

A prophylactically oriented concept of periodontal treatment is inconceivable without purpose-trained personnel. This fact led to the new profession of dental hygienist, being introduced into many countries more than 15 years ago. In Germany, attempts were made to close the gap with the profession of dental assistant (ZMF). This model has, however, proved a failure because--besides the advanced training curriculum not being sufficiently specialized--the demand for dental assistants is far greater than the supply. Many dentists, therefore, employ assistants with relevant training in the form of updating courses. Apart from the fact that this frequently results in legal misgivings, it also fails to meet the demand. For this reason, it is absolutely essential that personnel structures be adapted nationwide to a prophylactically oriented concept of periodontal treatment. Account is being taken of experience already gained abroad, as well as current opportunities for training and advanced training in Germany, including the legal principles valid in this country.

[Fracture rate of Dicor crowns under clinical conditions]. / Frakturrate von Dicor -Kronen unter klinischen Bedingungen.

Failure-time analysis of Dicor single crown restorations: Statistical methods of survival-analysis according to Kaplan-Meier were applied to investigate the effects of the fracture of 159 Dicor-restorations in 82 patients in a private dental office. After 33 months of service 77% (+/- 15%; 95% Conf. Int. for the mean) of the crowns were still under risk. Fractures were very high in molar crowns.

The role of the prosthodontist in the treatment of periodontal disease.

The inter-relationships between the periodontal situation of a patient and a prosthetic appliance should be regarded in particular from the aspect of oral hygiene. Creating or maintaining a high standard of oral hygiene is thus the joint objective characterizing cooperation between the periodontist and the prosthodontist. The tasks falling to the prosthodontist during initial therapy are: removal and temporary replacement of restorations that are not conducive to good oral hygiene, temporary replacement of teeth with hopeless prognoses, and temporary prosthetic planning in conjunction with the periodontist. In the phase of surgical periodontal treatment, the creation of new attachments should be accompanied by morphologic corrections; these are essential to the oral hygiene of patients with prosthetic appliances. The prosthodontist has therefore to advise the periodontist on what corrections are desirable and where. This applies firstly to gingival corrections at abutment teeth and secondly to mucosal corrections on the edentulous alveolar ridge. On conclusion of the periodontal treatment, the prosthodontist will have to come to terms with three problems: the indication for prosthetic treatment, the decision between fixed bridges and removable partial dentures, and the periodontal problem zones occurring with crowns and bridgework. The indications for prosthetic treatment can now be more restricted, following recent findings on oral function with shortened dental arches. When deciding between fixed bridges and removable partial dentures, it is the oral hygiene aspect that is decisive. In existing or threatened free-end situations preference should be given to bridgework. This can be implemented with: cantilever bridges, bridges abutted at each end by the distal movement of a premolar, and bridges abutted at each end by hemisectioning of a periodontally damaged molar. With crowns and bridges, prospects for oral hygiene are determined by the following: the position of the crown margin, the contour of the crown in the marginal area, and the contour of the under-surface of the pontic. If optimum prospects for oral hygiene have been created by good coordination between the periodontist and the prosthodontist, the prognosis in the maintenance phase is considerably improved.

Periodontal and prosthetic treatment in patients with oral lichen planus.

The problems of periodontal and prosthetic treatment are demonstrated with a typical case of oral erosive lichen planus with gingival involvement. The results attained suggest that oral lichen can be improved by optimum plaque control and periodontal treatment. Prosthetic treatment should be based on bridgework and not on removable partial dentures owing to the isomorphous irritant effect that characterizes lichen planus. Once the plaque situation is firmly under control, even teeth with advanced destruction of the supporting tissues may be used as abutments. In the event of all molars being absent, cantilever bridges should be fitted. In this case it is not essential to replace all the molars provided that the masticatory function is subjectively adequate.

A 3-year study of hemisectioned molars.

Over a period of 1-7 (average 2.9) years, 34 hemisectioned molars were examined clinically and radiographically. All patients were kept on a 3-6 month recall system. The indications for hemisectioning were periodontal in 9 cases and endodontic in 20 cases. In 4 cases extensive carious destruction, and in 1 case an external granuloma led to hemisectioning. Mainly mandibular molars were treated (27). Root resectioning was carried out on only 7 maxillary molars, 22 of the treated teeth were used as distal abutments for small fixed bridges. For a further 3 the same was planned. The remaining treated teeth were singly crowned. Of the 34 treated molars, 7 were considered failures, 6 for endodontic reasons (apical periodontitis) and only 1 for periodontal reasons. No correlation between failure and the length of the follow-up period was found. With 17 of the 34 molars a significant reduction in periodontal pocket depths was recorded between commencement of treatment and the final examination. No difference in periodontal pocket depth or in the height of the alveolar crest was found between hemisectioned and non-hemisectioned surfaces. The mobility of hemisectioned molars was difficult to judge because 22 of the 31 crowned teeth were used as abutments for bridges. 17 of the 22 bridges were firm, 4 showed mobility of 1 degree, and 1 mobility of 11 degrees. Of the singly crowned teeth, only 1 exhibited mobility of 111 degrees. This study indicates that the prognosis for hemisectioned teeth is favourable. Failures were primarily endodontic in origin rather than periodontal. Periodontal damage can be kept to a minimum by regularly reviewing oral hygiene standards. Treated teeth may be used as abutments for small bridges if attention is paid to achieving optimal articulation.