Changes in the Outcome of Metal-Ceramic Tooth-Supported Single Crowns and FDPs Following the Introduction of Osseointegrated Implant Dentistry into a Prosthodontic Practice

Purpose: The aim of this study was to prospectively analyze the effect that the incorporation of osseointegrated implant dentistry had on the outcome of metalceramic tooth-supported prostheses that had been in situ for 5 to 10 years. Materials and Methods: The 10-year estimated (Kaplan-Meier) cumulative survival of metalceramic tooth-supported single crowns (TSCs) and metal-ceramic tooth-supported fixed dental prostheses (TFDPs) provided for all patients treated at two time periods was determined and statistically compared (log-rank test). Prostheses in group 1 (404 TSCs and 433 TFDP abutments in 189 TFDPs) were cemented between January 1989 and December 1993, with the outcome determined in 1998. Prostheses in group 2 (539 TSCs and 354 TFDP abutments in 142 TFDPs) were cemented between January 1997 and December 2001, with the outcome determined in 2006. A 500% increase in implants restored occurred between the end of group 1 and group 2 time periods. Results: For TSCs, comparison between groups showed a significantly better survival in group 2 than in group 1 for nonvital TSCs (P = .001), nonvital maxillary anterior teeth (P = .003), nonvital maxillary lateral incisors (P = .008), and nonvital premolars (P = .013). Comparison within groups showed nonvital TSCs had a significantly decreased survival compared to vital TSCs in group 1 (P .001), but not in group 2 (P = .48). Overall, the estimated cumulative 10-year survival of TSCs in group 2 was 94% ± 3%. For TFDPs, comparison between groups showed a significantly better survival for nonvital abutments in group 2 than in group 1 (P = .049). Comparison within groups showed nonvital TFDP abutments had a significantly decreased survival compared to vital TFDP abutments in group 1 (P = .001), but not in group 2 (P = .377). Overall, group 2's estimated cumulative 10-year survival for all TFDPs was 90% ± 6% and for three-unit TFDPs was 97% ± 2%. Teeth in group 2 failed less through fracture and periodontal disease than those in group 1. Conclusions: The incorporation of osseointegrated implant dentistry has resulted in a significant improvement in the survival of TSCs and TFDP abutments, nonvital and vital teeth having equivalent survivals for TSCs and TFDPs, and a decrease in supporting-tooth failure through fracture and periodontal disease.