Influence of intracoronal bleaching agents on the bond strength of MTA cements to composite resin and their surface morphology

The objective of the present in vitro study was to evaluate micro-tensile bond strength (µSBS) of MTA cements to composite resin using a universal adhesive after internal bleaching procedure, and to examine surface characteristics of MTA cements exposed to bleaching agents. MTA specimens were divided into three subgroups according to the bleaching agent used which were, 37% carbamide peroxide (CP), 35% hydrogen peroxide (HP), and no exposure as a control group ( n = 12). After exposure to bleaching agent, composite resins were applied to MTA surfaces using a universal adhesive in self-etch mode. The specimens were exposed to a shear force until failure to evaluate bond strength. MTA surfaces were investigated using scanning electron microscopy (SEM) to observe the effects of the bleaching agents. Differences between groups were analyzed using two-way ANOVA test and intergroup comparisons were assessed with Tukey test ( p