Kaus, Thomas

Objective: The technique of resin-bonded fixed partial dentures (RBFPD) is a well-accepted clinical technique to replace missing teeth. The survival rates reported in the literature vary widely, and the conclusions are sometimes conflicting. This study presents the clinical long-term performance of silicoated RBFPDs and also determines the main cause of failure. Method and materials: Sixty-one patients with a total of 74 RBFPDs were either examined or requested to complete a questionnaire regarding their fixed partial dentures. Sixty-four were placed in the anterior region, and 10 in the posterior region. No more than one missing tooth in the posterior area and two missing teeth in the anterior region were replaced with RBFPDs. A retentive preparation was made on the abutment teeth. All the RBFPDs were adhesively seated. Results: Eighteen RBFPDs failed after a mean observation time of 7.8 years (nine retention losses of one or more retainers, six carious lesions, and three veneer fractures occurred). Seven RBFPDs were rebonded, whereas the remaining 11 failures had to be replaced with conventional FPDs. Fifty-six RBFPDs were primary restorations, and seven secondary RBFPDs were used after the loss of the primary restoration. A mean survival rate better than 69% after a 13-year observation period was calculated. Including the rebonded restorations, a mean functional survival rate of 83% was estimated. A total of 18 failures (24.3%) of all restorations were observed, the main cause being loss of retention. Conclusion: Silicoated RBFPDs are a viable treatment means with an acceptable success expectancy.

The aim of the current ongoing study is to evaluate the long-term results of endosseous implants placed into autogenous bone grafts from intraoral donor sites. Patient selection for the correction of bone deficiencies was based on biomechanical and esthetic needs. Donor site selection was dependent upon the type of deficiency and the graft shape needed. Two-stage implants were placed after a healing period of 3 to 6 months, based on an assessment of the graft viability with radiographic and clinical parameters. Thus far, 118 implants have been placed in 60 patients whose alveolar ridges were deficient in height, width, or both height and width and were augmented. The patients were observed for up to 77 months. Two implant failures were encountered before implant exposure (1.7%). No further implants have been lost in function.

A total of 2,261 2-stage implants was placed in 467 patients in combination with angled abutments ranging from 0 to 45 degrees. These were observed over a period of up to 96 months, with a mean observation time of 28.8 months. Single and multiple teeth were replaced and restored using angled abutments. For patients who contributed multiple survival data, the data were considered dependent. Therefore, a mean survival estimation was performed. With a certainty of 95%, an estimated mean survival rate better than 98.6% after a 5-year observation period was calculated. The statistical comparison of 2 independent, randomized implant groups (with abutments angled between 0 and 15 degrees and between 20 and 45 degrees) by means of a log-rank test showed a probability of 0.84 (P value) that the survival functions are the same for both groups. Good esthetic and functional outcomes were observed. Keywords: dental abutments, osseointegrated dental implants, survival analysis

With the technique of maxillary ridge expansion, 449 implants were placed in 150 patients and observed over a period of up to 93 months. Thin maxillary ridges of adequate height and comprising 2 separate cortical plates with intervening cancellous bone were selected for maxillary ridge expansion and simultaneous implant placement. Two-stage implants were used and allowed to heal in a closed environment for 6 months prior to loading. Single and multiple teeth were replaced using this technique, and an estimated mean survival rate better than 97% after a 5-year observation period was calculated (95% confidence interval of the mean survival estimation: 98% ± 1%). Good esthetic and functional outcomes were observed. Keywords: alveolar ridge augmentation, dental implants, endosseous dental implantation, osteotomes, ridge expansion

74 resin-bonded fixed partial dentures (RBFPD's) were placed with 61 patients consecutively, since 1986. Increased mechanical retention of the FPD's was achieved by preparation of horizontal ledges and vertical grooves. 52 were 3-unit anterior, 4 4-unit anterior, 8 6-unit anterior, 1 7-unit anterior, 8 3-unit posterior and 1 4-unit posterior restoration. 60 were cast in a NiCr-alloy (Wiron88, Bego Co.), and 13 in a CoCr-alloy (Remanium CD, Dentaurum Co.) and veneered with Vita VMK68 ceramics. All restorations were seated with Microfill pontic (Kulzer Co.) bis-GMA resin cement after silicoating with the Silicoater (Kulzer) and silane treaetment (Silicoup, Kulzer). Patients were monitored at least once a year. 29 patients were rated as drop-out, as they did not appear for recall for more than one year within the observation period. Results: 14 primary failures (19% of all retorations), i.e. retention loss of one or more retainers, were observed after a mean function time of 4.15 years. Survival rate with regard to primary failures was 0.76 after 120 months (determined by Kaplan-Meier method). 6 failed FPD's were rebonded, thus a survival rate of 0.87 after 120 months of functioning restorations was calculated. With 4 restorations veneer fractures occurred, however, the veneer could be repaired. It is concluded, that silicoated resin-bonded FPD's with a preparation design for increased mechanical retention are a viable treatment means with an acceptable success expectancy. Keywords: resin-bonded fixed partial dentures, bridgework, adhesives, clinical study