Evaluation of the effect of gallic acid dentin treatment on the shear bond strength of the composite resin by using universal adhesive, in self-etch and total-etch strategies.

Abstract

Background: Gallic acid (GA), as a material with potentially beneficial effects in dentistry, was used in this study to investigate whether it affects the shear bond strength of composite to the dentin via self-etch and total-etch strategies of a universal adhesive.

Material and methods: Sixty intact molars with sectioned flat occlusal surfaces were treated with 1 wt.% and 2 wt.% GA solution before applying the universal adhesive in self-etch and total-etch modes. They were randomly divided into six groups (n=10): 1) self-etch control, 2) total-etch control, 3) 1% GA + self-etch, 4) 2% GA + self-etch, 5) 1% GA + total-etch, and 6) 2% GA + total-etch. Teflon molds were fixed on the prepared dentin surface, and then the composite was inserted into the molds and light cured. After spending 24 hours in a storage condition with 100% humidity at room temperature, specimens underwent the SBS test. The SBS values calculated by the universal testing machine were analyzed using ANOVA and Tukey's post hoc tests (p< 0.05).

Results: The application of 1% and 2% GA before using the universal adhesive revealed a significant increase in the mean SBS values compared to respective control groups (p< 0.001, p< 0.001), and the mean values for 1% GA were significantly higher than 2% GA in both etching strategies (p< 0.001, p< 0.001). The groups that utilized the universal adhesive with the total-etch method exhibited statistically higher SBS values than those using the self-etch approach, irrespective of applying GA and its concentration (p< 0.001).

Conclusions: Applying 1% and 2% GA improved the shear bond strength of composite resin to the dentin in both self-etch and total-etch approaches with the universal adhesive. These findings indicate that GA holds great potential for expanded clinical applications. Key words:Gallic acid, shear bond strength, universal adhesive.