Influence of in vitro irrigation protocols on root canal treatment for bond strength to enamel and coronary dentin

Abstract

Introduction: The purpose of this study was to evaluate the effects of different concentrations of chitosan solution used as a final rinse after root canal treatment on the shear bond strength of composite resin to enamel and coronary dentin. Materials and Methods: Sixty-four enamel/dentin fragments were taken from the cervical-third of bovine teeth. The specimens were randomly divided into four groups according to the irrigation protocol (0.2% chitosan, 0.5% chitosan, 1% chitosan, and 17% ethylenediaminetetraacetic acid [EDTA]-control) and in two subgroups according to the substrate (enamel or dentin). Each specimen was fixed in a metallic clamping device and composite resin (Single Bond/z350) was inserted in two increments and polymerized for 20s. The microshear bond strength was performed, and the adhesive interface was analyzed by three-dimensional laser confocal scanning microscopy. The data were analyzed using a two-way ANOVA and Tukey's test (α = 5%). Results: For the irrigation protocol, bond strength was significantly higher for all chitosan solutions compared to the 17% EDTA-control solution. All chitosan solutions, 0.2%, 0.5% and 1.0%, were statistically similar to each other (P > 0.05). For the substrate, enamel showed greater bond strength and was significantly different from dentin (P < 0.05). For interaction factor, 1% chitosan solution presented bond strength values statistically superior to the 17% EDTA control solution (P < 0.05) in dentin. The adhesive fracture was the most prevalent for all groups. Conclusion: The irrigation protocol on the root canal treatment does not affect the enamel bond strength and 1% chitosan solution improved dentin bond strength. Bond strength was higher for enamel than for coronary dentin.

Keywords

• chitosan
• composite resin
• dentin
• enamel
• root number
• shear strength