Effects of an endodontic auxiliary chemical substance on the bond strength of two methacrylate-based endodontic sealers to dentin.

PURPOSE: To evaluate the influence of irrigation protocols and drying procedures on the bond strength of two methacrylate-based sealers to dentin and the associated failure pattern using scanning electron microscopy (SEM).

MATERIALS AND METHODS: Fifty single-rooted human teeth were prepared with an irrigation protocol using either 5.25% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) and 17% EDTA (ethylenediaminetetraacetic acid) for smear layer removal. The following subgroups were also created based on drying of the root canal walls: paper points, the canals were blot dried with paper points with the last one appearing dry; or, ethanol, excess distilled water was removed with paper points followed by dehydration with 95% ethanol for 1 min and blotting with paper points. Each group was divided into two subgroups on the basis of the root canal sealer: EndoREZ and RealSeal SE. Bond strength was measured by the push-out test. The data were analyzed by ANOVA/Tukey HSD (α = 0.05). Failure patterns were classified as adhesive, cohesive, and mixed in the SEM analysis. The failure mode was evaluated by the chi-squared test (α = 0.05).

RESULTS: The roots irrigated with NaOCl showed significantly lower bond strength than the roots irrigated with CHX (p < .05). RealSeal SE showed higher bond strength when compared with EndoREZ (p < .05). The highest values of bond strength were in the CHX and ethanol groups with RealSeal SE (p < .05). An increase in adhesive failure was observed in the NaOCl and EDTA group.

CONCLUSIONS: The bond strength of both methacrylate-based sealers is influenced by the irrigant protocol.