Ion release from a composite resin after exposure to different 10% carbamide peroxide bleaching agents

objective: this in vitro study evaluated the influence of two 10% carbamide peroxide bleaching agents - a commercial product (opalescence pf; ultradent products, inc.) and a bleaching agent prepared in a compounding pharmacy - on the chemical degradation of a light-activated composite resin by determining its release of ions before and after exposure to the agents. material and methods: thirty composite resin (filtek z250; 3m/espe) samples were divided into three groups: group i (exposed to opalescence pf commercial bleaching agent), group ii (exposed to a compounded bleaching agent) and group iii (control - milli-q water). after 14 days of exposure, with a protocol of 8 h of daily exposure to the bleaching agents and 16 h of immersion in milli-q water, the analysis of ion release was carried out using a hp 8453 spectrophotometer. the values were analyzed statistically by anova, tukey's test and the paired t-tests. the significance level was set at 5%. results: after 14 days of the experiment, statistically significant difference was found between group ii and groups i and iii, with greater ion release from the composite resin in group ii. conclusions: the compounded bleaching agent had a more aggressive effect on the composite resin after 14 days of exposure than the commercial product and the control (no bleaching).