Effects of attrition, prior acid-etching, and cyclic loading on the bond strength of a self-etching adhesive system to dentin

The purpose of this study was to evaluate the effects of dentin attrition, phosphoric acid etching, and cyclic loading on the microtensile bond strength (μTBS) of a self-etching adhesive system to dentin. Flat dentin surfaces of human molars were assigned to eight experimental groups based on those with or without attrition, prior acid-etching, and cyclic loading. Resin composite paste was placed and polymerized after the bonding procedure according to manufacturer's instructions. The specimens were subjected to μTBS testing at a crosshead speed of 0.5 mm/min. Results showed that the minimum mean value of μTBS was 14.9 MPa in the group without attrition and acid-etching but with loading, while the maximum mean value of μTBS was 40.0 MPa in the group without attrition and loading but with acid etching. Therefore, the value of μTBS to dentin without attrition was significantly decreased by cyclic loading but that to dentin with attrition was not affected.