RESUMO
OBJECTIVES: This study examined the effect of 2% chlorhexidine on the microTBS of a direct composite restoration using one-step self-etch adhesives on human dentin. MATERIALS AND METHODS: Twenty-four extracted permanent molars were used. The teeth were assigned randomly to six groups (n = 10), according to the adhesive system and application of chlorhexidine. With or without the application of chlorhexidine, each adhesive system was applied to the dentin surface. After the bonding procedure, light-cure composite resin buildups were produced. The restored teeth were stored in distilled water at room temperature for 24 hours, and then cut and glued to the jig of the microtensile testing machine. A tensile load was applied until the specimen failed. The failure mode was examined using an operating microscope. The data was analyzed statistically using one-way ANOVA, Student's t-test (p < 0.05) and Scheffe's test. RESULTS: Regardless of the application of chlorhexidine, the Clearfil S3 Bond showed the highest microTBS, followed by G-Bond and Xeno V. Adhesive failure was the main failure mode of the dentin bonding agents tested with some samples showing cohesive failure. CONCLUSIONS: The application of 2% chlorhexidine did not affect the microTBS of the resin composite to the dentin using a one-step self-etch adhesive.