Factors associated with the longevity of resin composite restorations.

This study investigated factors associated with the longevity of resin composite restorations, which were placed in 97 patients (mean age of 58 years) by 24 dentists in Nagasaki University Hospital between 1995 and 2005. All patients were under the charge of the principal investigator (SK) and most of them had been regularly checked up for up to 11 years. A total of 503 resin composite restorations (433 by SK and 70 by the other dentists) were analyzed by the Kaplan-Meier and the Cox proportional hazards model. Ten-year survival rates were 84.2% for SK and 71.8% for the others, showing a significant difference. Although the retreatment risk had a great influence on the survival time, gender and age at placement did not have. There were no significant differences in survival between conventional 2-step etch-and-rinse, 2-step self-etch adhesives with and without prior enamel etching. Cavity type had a significant influence, whereas tooth type had no effect.