The purpose of this in vitro study was to evaluate the influence of different irrigation solutions on the microshear bond strength of a universal adhesive system applied in etch & rinse mode and self-etch mode to dentin-enamel junction (DEJ), coronal dentin, pulp chamber dentin, and floor of the pulp.
The specimens were randomly divided into 4 main groups according to the irrigation solutions used: Group 1-distilled water (control), Group 2-NaOCl [Sodium hypochlorite], Group 3-NaOCl combined with 17% EDTA [Ethylenediaminetetraacetic acid] and Group 4-chlorhexidin gluconate. Additionally, each main group was divided into the 2 subgroups (n = 15) according to the application mode of the Single Bond Universal Adhesive system. After applying the adhesive to the dentin, a vinyl tube was placed on the dentin-enamel junction and dentin surfaces, then Filtek Bulk Fill Posterior composite was packed into the cylinder's lumen and was light cured. The specimens were stored in water at 37 ℃ for 24 h. A universal testing machine was used for the microshear test. The data in MPa units were subjected to two-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). Scanning electron microscope analysis was performed on all tested samples.
Distilled water was found to have a statistically higher bond strength compared to the other irrigation solutions. No statistically significant differences were found (P > 0.05) when bond strength was compared between etch-and-rinse mode, and self-etch mode of adhesive systems. The mean bond strength of floor pulp dentin groups was significantly lower than that of other regions (P < 0.05).
The chemical irrigant solutions and dentin regions influenced the adhesive bond strenght.