LAUSR

The aim of this study was to evaluate the effect of chlorhexidine (CHX) dentin treatment on microtensile bond strength ( μTBS) of adhesive systems in different storage times. Occlusal enamel was removed from ninety third-molars and flat surfaces of middle dentin were exposed. Teeth were randomly divided in 6 groups according to adhesive system (etch-and-rinse : Adper Sco tchbond 1XT ASB ; self-etch: Adper Prompt L-Pop – APP; and universal: Single Bond Universal SBU) and chlorhexidine (CHX) dentin treatment (2 % CHX application for 20 s prior Primer). After resin composite build up, teeth were sectioned to obtain beam spec imens and divided in 3 subgroups (n=5): 72h, 3 and 6 months storage times. After the storage times, teeth were tested in tension unti l failure (0.5 mm/min). SEM was performed to observe hybrid layer of adhesive systems. Data were analyzed using one-way ANOVA and Tukey tests. At 72 h, all equivalent groups (same adhesive system, different dentin treatments) maintained their μTBS when compared CHXtreatment. At 3 and 6 months, non-treated CHX groups showed less μTBS than CHX-treated ones. Six months storage time did not significantly decrease μTBS, except for G2-ASB. The effect of CHX on dentin μTBS depends on storage times and adhesive systems. While immediate μTBS was not affected by CHX treatment, CHX improved dentin μTBS after 3 and 6 months.