Microtensile bond strength of direct and indirect composite resin restorations

Abstract

The aim of this study was to evaluate the microtensile bond strength to dentin of direct and indirect composite resin restorations. Thirty sound human molars had their occlusal surfaces cut 2 mm below the cusps, resulting in flat dentin surfaces. The teeth were divided into two groups: G1 (indirect) the dentine was isolated and the plateaus made from resin composite dislocated, treated with aluminum oxide and cemented with adhesive system and resin cement; G2 (direct) the composite restoration confectioned directly on the dentin surface with the same adhesive system. The teeth were cut to provide three hourglass-shape specimens per tooth (n = 45). The specimens were submitted to a microtensile test at 0.5 mm/min. Data were analyzed by Student t test (p > 0.01). Mean and standard deviation values (in MPa) were: G1 = 22.02 (± 12.47); G2 = 23.35 (± 9.82). There was no statistical differences in the mean microtensile bonding strength values between direct and indirect resin composite restorations. Key words: Bond strength. Microtensile test. Adhesive system. Resinous cement.