In a recent clinical retrospective study evaluating 515 metal-ceramic FPDs, Walton calculated that the cumulative survival rate of metal-ceramic FPDs was 96% for 5 years, 87% for 10 years, and 85% for 15 years of service.
49 This cumulative survival rate was not related to the number of units restored by an FPD. Of the evaluated
metal-ceramic FPDs, 299 were 3-unit metalceramic FPDs. In light of these current findings demonstrating the expected survival rate of the current standard of care, all-ceramic FPDs should demonstrate at least a similar survival rate in clinical studies to be considered a predictable restorative alternative. Walton also reported that modes of failure for metal-ceramic FPDs included tooth fracture, 38%; periodontal breakdown, 27%; loss of retention, 13%; and caries, 11%.50 An earlier study showed that the primary cause of failure was dental caries (38%). Other modes of failure included delamination of the veneering porcelain, cement dissolution, defective margins, abutment fracture, dowel and core/root fracture, periodontal disease/abutment mobility,and periapical lesion resulting from pulpal involvment.51
The scientific clinical data available regarding the success of some of the all-ceramic systems for FPDs is limited in terms of the follow-up period because these restorations are relatively new