Longevity of Resin Composite Restorations

Objective: The purpose of this retrospective study was to investigate the longevity of resin composite restorations. Methods: Longevity of 1107 resin composite restorations, which were placed in 123 patients by 50 dentists in Nagasaki University Hospital from 1982, was studied using the patient records. All patients (mean age at the investigation: 61.4, range: 19.4-85.9, mean DMFT: 18.9, mean age at placement: 53.3) were under charge of a principal investigator. Clinical performances of the restorations in 104 patients were examined by the investigator from May to November in 2005. If patients were not examined during this period, the fates of the restorations were considered to be censored up to the last observation. In addition, when the restorations had been replaced or lost, the history of them was also investigated. The data were statistically analyzed by the Kaplan-Meier and the log-rank test (p<0.05). Results: The estimated 10-year and 20-year survival rates were 67.8% and 58.4% for Class 1, 73.1% and 64.9% for Class 2, 78.8% and 65.3% for Class 3, 56.4%, and 42.3% for Class 5 restored with older adhesive systems, respectively. Longevity of Class 2 and 3 resin composite restorations was superior to that of Class 5 restored with older adhesive systems. In contrast, longevity of Class 5 restored with newer self-etch or 2-step total-etch systems demonstrated a significantly higher survival rate at 10 years (87.3%) compared to that of other groups. The primary reason for failure of resin composites varied with classification of restorations. Fracture, caries and loose/lost mainly related to Class 1 & 2, Class 3 and Class 5, respectively. Conclusion: Within the limits, the findings of this study suggest that approximately 60% of resin composite restorations would survive 20 years after placement. Supported by Grant-in-Aid from JSPS, Japan (C 16591918).