The effect of concentration and application time of hydrogen peroxide on the microtensile bond strength of resin restorations to the dentin at different depths

Abstract

The purpose of this study was to examine the effect of hydrogen peroxide at different application time and concentrations on the microtensile bond strength of resin restorations to the deep and the pulp chamber dentin.A conventional endodontic access cavity was prepared in each tooth, and then the teeth were randomly divided into 1 control group and 4 experimental groups as follows: Group 1, non treated; Group 2, with 20% Hydrogen peroxide(H2O2); Group 3, with 10% H2O2; Group 4, with 5% H2O2; Group 5, with 2.5% H 2O2; the teeth of all groups except group 1 were treated for 20, 10, and 5min. The treated teeth were filled using a Superbond C&B (Sun medical Co., Shiga, Japan). Thereafter, the specimens were stored in distilled water at 37℃ for 24-hours and then sectioned into the deep and the chamber dentin. The microtensile bond strength values of each group were analyzed by 3-way ANOVA and Tukey post hoc test(p < 0.05).In this study, the microtensile bond strength of the deep dentin (D1) was significantly greater than that of the pulp chamber dentin (D2) in the all groups tested. The average of microtensile bond strength was decreased as the concentration and the application time of H2O2 were increased. Analysis showed significant correlation effect not only between the depth of the dentin and the concentration of H2O2 but also between the concentration of H2O2 and the application time(p < 0.05), while no significant difference existed among these three variables(p > 0.05). The higher H 2 O 2 concentration, the more opened dentinal tubules under a scanning electron microscope(SEM) examination.[J Kor Acad Cons Dent 34(5): [406][407][408][409][410][411][412][413][414] 2009]