Micro-tensile and micro-shear bond strengths of current self-etch adhesives to enamel and dentin

Purpose: To evaluate the micro-tensile and micro-shear bond strengths of self-etch adhesives to enamel and dentin. Methods: Extracted human molars were ground to expose flat enamel or dentin surfaces using wet #600 grit SiC paper. The enamel and dentin surfaces were assigned to four groups of four adhesives: three one-step self-etch adhesives (Clearfil S3 Bond; AQ Bond Plus, G-Bond) and a two-step self-etch adhesive (Clearfil SE Bond). Each of the adhesives were applied to the ename or dentin surfaces in accordance with the manufacturers' instructions and restored with resin composite (Clearfil AP-X). The bonded teeth were then prepared for either micro-tensile or micro-shear bond strength tests. After storage in saline at 37°C for 24 hours, specimens were stressed at a crosshead speed of 1 mm/minute. Mean bond strengths and modes of failure were analyzed using one-way ANOVA followed by Scheffe's F test and the Chi-square test, respectively, at a 95% level of confidence. Results: SE Bond produced significantly higher values than the one-step adhesives in the micro-shear bond test to enamel (P< 0.05), while no significant differences were found among the adhesives in the micro-tensile bond test (P> 0.05). For dentin, SE Bond showed the highest bond strengths in both micro-tensile and micro-shear bond tests; values were significantly higher than both AQ Bond Plus and G-Bond (P< 0.05).