| Summary: | Objective: to evaluate the bond strength of composite resin to bovine enamel after bleached surfaces were treated with two different reducing substances. Material and Methods: bovine teeth were embedded, had their buccal face planed and were divided into 4 groups (n=10). Group 1 (control) was not subjected to bleaching, acid etched and restored with adhesive and composite resin. Groups 2 to 4 were bleached with 35% hydrogen peroxide during 4 consecutive days for 40 min/session and subjected or not to the proposed surface treatments before being restored. Group 2 was bleached and restored, while Groups 3 and 4 were bleached and immersed in sodium thiosulfate or sodium ascorbate solution, respectively, before being restored. Samples were stored for 24 hours and then submitted to a microshear strength test. Results: according to the statistical tests, the bond strength results using reducing agents were similar to those of the control group and statistically different from those of the only-bleached group. Conclusion: the reducing solutions were capable of recovering the bond strength of freshly bleached teeth without statistically significant difference between them.
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