The effects of anti-oxidant agents as neutralizers of bleaching agents on enamel bond strength

The aim of this study was to investigate the neutralizer effect of antioxidant agents on the bond strength of bleached enamel. Buccal enamel surfaces of 80 bovine incisors were divided into eight groups. The negative control group (NC) received no bleaching treatment and the other groups were bleached with 35% hydrogen peroxide gel for 30min., activated with a photocuring unit. Ten specimens were selected for the positive control group (PC) and received no anti-oxidant agents. The remaining bleached specimens received one of the six anti-oxidant agents, for 20min (10% Sodium Ascorbate–SA; Catalase–CA; Glutathione Peroxidase–GP; Acetone–AC; Ethanol–ET; 7% Sodium Bicarbonate– SB). Bonds were formed and shear bond test was carried out after 24h. The data were analyzed by one-way ANOVA and Tukey’s tests (α =5%). The PC group showed significantly lower bond strength mean than the NC group. All of the experimental groups showed bond strength means significantly lower than the NC group. The CA group showed significantly higher bond strength mean than the bleached PC group and the groups SA, GP, AC, ET and SB showed no significant differences compared to PC group. It was concluded that only the Catalase application resulted in significant increase of bond strengths in relation to the PC group and that none of the treatments was able to completely neutralize the deleterious effects of bleaching on bond strength