Shear bond strength of resin composite to enamel and dentin submitted to a carbamide peroxide dentifrice

To assess the shear bond strength of resin composite to human enamel and dentin after using a whitening dentifrice containing carbamide peroxide for 21 days.

Thirty enamel and 30 dentin slabs were embedded, flattened and randomly divided into three groups (n=10) that received different treatments: carbamide peroxide containing dentifrice (Rembrandt Plus), fluoride containing dentifrice (Close Up with fluoride), and immersion in artificial saliva as the control group. Applications were made for a 15-minute period daily, immersing the slabs in a suspension with distilled water and dentifrice in the ratio of 3:1 (weight) for 21 days. For the rest of the time, the slabs were kept in an artificial saliva solution. After the last application, an adhesive system (Single Bond) was used to bond resin-based composite cylinders (Z100) to the enamel and dentin surfaces for the shear bond strength tests. These tests were carried out in a universal testing machine at a speed of 0.5 mm/minute.

ANOVA and the Tukey test for enamel and Kruskal-Wallis and the Dunn Method for dentin, showed significant differences between slabs treated with Rembrandt Plus (REM) and the artificial saliva control group, with higher values for REM (P < 0.05). There were no differences in mean bond strengths of enamel and dentin treated with Close Up with fluoride (CLO) and REM, nor were any differences shown between CLO and the artificial saliva control group. A whitening dentifrice containing carbamide peroxide increased the bond strength of restorative systems.