Methods: Clinical studies on posterior composite exceeding 5 year observation time and investigating class II restorations were selected. Authors were invited to deliver the raw data of their class II restored teeth for the specific study. For 12 studies, these data could be retrieved and transformed into one database. Included were brands of used composite, bonding and base materials, number of restored surfaces, tooth number, patients age and gender, date of placement, date of censoring or failure including reason for failure and the caries risk of patients. Statistical analysis: Kaplan Meier statistics were applied and log-rank tests at p<0.05 were used to define differences between groups.
Results: Data for 2816 class II restorations extracted from 12 clinical studies were analyzed. The annual failure rate of class II composite restorations was 2,35% over a 10 year period. Patients with a medium or high caries risk had significantly more risk for failure (p<0.001). No differences in longevity between restorations placed with highly filled and medium filled hybrid composites could be found (P>0.05).
Conclusions: In this meta analysis on 12 studies, class II posterior composite restorations exhibited annual failure rates between 2 and 3 percent. Increased failure rate for patients with high caries risk was found