Effect of resin composite adhesion on marginal degradation.

Inappropriate bonding treatment tends to result in marginal fractures or microleakage caused by masticatory loading. The purpose of this study was to investigate the effect of adhesion of resin composites on marginal degradation. Five posterior resin composites were inserted into Class I preparations with and without etching or bonding treatment. These restored teeth were subjected to a three-body wear test for 400,000 cycles, and the exposed enamel height at the tooth/restoration interface was determined by profilometer and scanning electron micrography (SEM). It was found that use of appropriate etching and bonding agents reduced the exposed enamel height and maintained marginal integrity after repeated loading.