Secondary caries susceptibility of teeth with long-term performing composite restorations

The aim of this study was to assess retrospectively the caries susceptibility of posterior teeth with composite restorations after 18 and 20 years. The sample was selected out of the recall of a dental office. Sixteen restorations were reassessed after 18 and 20 years. All findings have been rated according to the C criteria of the CPM index. For the micromorphological evaluation with SEM, replicas were made using a two-step impression technique. All restorations demonstrated marginal imperfections and a predominant rough surface. At the 18 year-evaluation two restorations exhibited secondary caries. Despite of extended marginal gap formations none of the 12 restorations reexamined at 20 years showed secondary caries. Direct composite restorations can serve over a long period of time despite of poor qualitative parameters. Micromorphological marginal deterioration and clinical gap formation do not necessarily result in a higher risk for secondary caries.