Survival Rate of 3-unit Fixed Partial Dentures Replacing First Molars: A Retrospective Cohort Study

Bull Tokyo Dent Coll . 2022 Nov 15. doi: 10.2209/tdcpublication.2022-0009. Online ahead of print. Abstract Fixed partial dentures (FPDs) made of 12% Au-Pd alloy are covered under Japan's national health insurance system. The survival rate of such 3-unit fixed FPDs remains unknown, however. The purpose of this retrospective study was to assess their survival rate in the replacement of first molars. A total of 140 FPDs were included, and the endpoint was removal of an FPD. During the observation period, 43 FPDs were removed. The FPD survival rate was 70.2% at 10 yr, 58.2% at 15 yr, and 42.1% at 20 yr according to the Kaplan-Meier method. The estimated mean survival period was 19.4 yr. The main reasons for FPD loss were dental caries (27.9%), separation from the abutment tooth (18.6%), and pulpitis (18.6%). Single factor analysis using the log-rank test showed that two factors influenced FPD survival: a smaller gonial angle and deep pockets around the abutment teeth. This effect was not statistically significant in either case, however (p>0.05). The present results suggest that the prevention of caries and of the separation of the dentures from the abutment teeth are important factors in the long-term survival of FPDs.

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