A 20-year retrospective survival study of fixed partial dentures.

PURPOSE: This study of fixed partial dentures (FPDs) evaluated the long-term efficacy and determined frequencies and causes of failures. MATERIALS AND METHODS: A total of 322 FPDs in 193 patients, fabricated at an undergraduate university clinic, were evaluated over a 20-year period. All patients were invited to participate in a supportive maintenance program. Failures of the FPDs were divided into irreversible complications (loss of FPD/abutment) and reversible complications (FPD intact after conservative treatment) and into biologic and technical/patient-related failures. RESULTS: The Kaplan-Meier survival rate after 20 years was 66.2%. Statistically significant differences in survival rates were found between FPDs without post-and-core abutment teeth as compared to FPDs with at least one post-and-core abutment tooth (P = .002) and for vital abutments versus post-and-core abutments (P = .001), but significant differences were not found between restorations in the maxilla and mandible (P = .27). Caries and loss of retention were the main reasons for failure and accounted for 61% of the failures. CONCLUSION: The survival of FPDs by undergraduate students at a university clinic during a 20-year period was comparable to the results published by university departments or general practitioners. Occurrence of a previously reversible complication is a predictive factor for an irreversible complication later on. A reversible complication within the first 2 years will probably lead to an early irreversible complication.