Clinical Performance of Tooth-implant- and Tooth-supported Zirconia-based Fixed-Dental-Prostheses

Objective: This study compared the clinical survival of tooth-implant (TI-S) and tooth (T-S) supported three-unit fixed dental prostheses (FDP) with zirconia substructures and described the incidence of biological and technical complications. Methods: Forty-four patients received 27 TI-S FDP and 22 T-S FDP. Twenty seven screw implants (Screw-Line, Camlog) with diameters of 3.8, 4.3 or 5.0 mm were inserted at the dislodged position of two missing posterior teeth. All implants were provided with customized all-ceramic abutments made of zirconium dioxide Y-TZP. The preparation of all abutments was performed according to guidelines for zirconia-based restorations. Zirconia substructures were fabricated by a CAD/CAM-system (Everest, KaVo) and veneered in powder build-up technique (Initial ZR, GC). All restorations were cemented with glass-ionomer. Baseline evaluation was performed 2 weeks after cementation with recall examinations performed at 6, 12, 24 and 36 months by calibrated investigators. Scanning electron microscopy was carried out on replicas of all FDP. Survival probabilities according to Kaplan-Meier were calculated. Gingival parameters were assessed and statistically evaluated. Results: The mean service time of the FDP was 35 (± 6) months. Two technical complications (fracture of veneering porcelain) were observed. No biological complication was recorded. The Kaplan-Meier survival probability was 95.9 % for all types of complications and 100 % related to restorations in service. The type of abutment support (TI-S vs. T-S) had no significant influence on the survival probability (p = 0.412, Log-Rank-Test). No difference of the gingival parameters was detected between implants and natural teeth. Conclusion: Tooth-implant supported zirconia-based FDP showed similar clinical performance compared to tooth-supported zirconia-based FDP. Within the limitations of this study tooth-implant supported FDP with zirconia substructures seem to be a reliable treatment option.

This study was supported by KaVo and Camlog.