Effect of a bleaching agent on abrasion of resin-based restoratives.

Purpose: To evaluate the effect of a 10% carbamide peroxide-containing bleaching agent on brushing abrasion of esthetic restorative materials.
Methods: Using a randomized complete block design, 150 specimens (n = 15) measuring 3 x 3 x 2 mm were fabricated into acrylic resin cylinders, using one of the restorative materials: a microfilled resin composite (Al), a hybrid resin composite (Ch), a flowable resin composite (Wa), a resin-modified glass-ionomer cement (Fj) and a polyacid-modified resin composite (Dy). The bleaching agent or artificial saliva (control) was applied for 2 hours/day. After that, 120 brushing strokes were simulated automatically and the samples were kept in artificial saliva. Such bleaching/brushing cycle was performed daily for 21 days. Wear depth was assessed using profilometry.
Results: Bleaching did not show significant effect on wear depth. There was a significant difference among the restorative materials. Tukey's test showed that (Al = Ch) < (Wa) < (Fj) and that Dy was only different from Fj.