Comparative evaluation of the effects of sodium ascorbate, alcohol, and calcium hydroxide on the bond strength of composite resin to dentin in non-vital teeth bleaching

Abstract

Aim: The aim of this in vitro study was to investigate the effects of sodium ascorbate, alcohol, and calcium hydroxide as a buffering agent on composite resin-dentin bond strength of non-vital teeth bleaching.

Methodology: For our study, we used 80 human upper central teeth. An endodontic access cavity was opened on the palatal surface of the teeth. The root portion of the teeth was removed 2-3 mm below the enamel-cementum junction. Sodium perborate was used for the nonvital bleaching of all teeth. Following bleaching, four experimental groups were created: sodium ascorbate, alcohol, calcium hydroxide, and a control group. 1x1 mm specimens were obtained using a precision cutting device in all four experimental groups restored with bond and composite resin. The specimens were then subjected to tension tests in a microtensile device, and the resulting data were compared in terms of composite resin-dentin bond strength.

Results: The study data were analyzed using the Kruskal-Wallis H test due to non-normal distributions of variables to compare groups. If the Kruskal-Wallis test indicated significant differences, a post-hoc multiple-comparison test was used to identify which groups differed. The Shapiro-Wilk test was used to determine whether the variables followed a normal distribution, based on the number of units. A statistically significant difference in binding strength was found between the study groups (p<0.05). Specifically, the binding strength value of the sodium ascorbate group was significantly higher than that of the calcium hydroxide and control groups (p<0.05). However, no statistically significant difference was observed between the other groups.

Conclusion: After non-vital bleaching, sodium ascorbate can be used to improve the bond strength between composite resin and dentin. Further studies are needed to support the effect of alcohol and calcium hydroxide applications on bond strength.