Long-Term Survival of Complete Crowns, Fixed Dental Prostheses, and Cantilever Fixed Dental Prostheses with Posts and Cores on Root Canal-Treated Teeth

Purpose: This study investigated the long-term survival of posts and cores on root canal-treated (RCT) teeth restored with complete crowns, fixed dental prostheses (FDPs), 3-unit FDPs, and cantilever FDPs (C-FDPs) made over a period of 16 to 20 years in an undergraduate clinic. Materials and Methods: Complete treatment and follow-up records of 1,037 complete crowns, 134 three-unit FDPs, 322 FDPs, and 168 C-FDPs were available for analysis. All RCT teeth studied had a post-and-core buildup. Kaplan-Meier survival curves were used to evaluate the different types of fixed restorations. Results: For complete crowns, the estimated survival rates at year 18 were 74.9% for the vital group and 79.4% for the RCT group (P = .602). For 3-unit FDPs, the survival rate at year 20 was 83.2% for the vital group and 60.5% for the RCT group (P = .108). For the FDPs, the survival rate at year 20 was 77.4% for the vital group, while for the RCT group with at least 1 RCT abutment, the survival rate was 56.7% (P = .002). For C-FDPs with vital abutments, the survival rate was 73.5% at year 16, while for the RCT group with at least 1 RCT abutment, the survival rate was 52.3% at year 18 (P .01). Conclusions: There was no statistically significant difference in the long-term survival of complete crowns on vital abutments versus post-and-core complete crowns or in the survival of 3-unit FDPs on vital abutments versus those with at least 1 RCT abutment. For FDPs with more than 3 units and C-FDPs, the use of a post-and-core abutment led to significantly more failures.