Micro-shear bond strength of resin-bonding systems to cervical enamel

Purpose: To evaluate the micro-shear bond strength of current adhesive systems to cervical and mid-coronal enamel. Materials and Methods: Two commercially available resin adhesives were investigated; a self-etching primer system (Clearfil SE Bond) and a one-bottle adhesive system (Single Bond) intended for use with the total-etch wet-bonding technique were employed. Two regions of enamel, cervical and mid-coronal regions, were chosen from the buccal surface of extracted molars and were then bonded with each adhesive system and submitted to the micro-shear bond test. In addition, the conditioned enamel surfaces without any bond and the enamel-resin adhesive interfaces were studied morphologically using scanning electron microscopy (SEM). Results: No significant differences were found between the adhesive systems used (P> 0.05). However, for both bonding systems, cervical enamel showed significantly lower bonding than mid-coronal enamel (P< 0.05). The relatively lower bond strengths obtained from cervical enamel probably resulted from its aprismatic structure, which appears to be more resistant to dissolving in acids than prismatic mid-coronal enamel.