Effect of intracanal irrigants on the bond strength of epoxy resin‐based and methacrylate resin‐based sealers to root canal walls

AIM: To assess the bond strength of Epiphany and AH Plus sealers to root canal walls using a push-out test after use of several endodontic irrigants. METHODOLOGY: Roots of 100 maxillary canines were sectioned horizontally 5 mm below the cemento-enamel junction to provide 4-mm-thick dentine disks that were embedded in acrylic resin and had their root canals prepared with a tapered bur (larger diameter=2.70 mm; smaller diameter=2.30 mm; length = 4 mm). The specimens were randomly assigned to five groups (n=20) according to the dentine surface treatment: I - 1% NaOCl (30 min); II - 1% NaOCl (30 min) + 17% EDTA (5 min); III - 17% EDTA (30 min); IV - 24% EDTA gel (30 min); V - 2% chlorhexidine gluconate (CHX) gel (30 min). In each group, two specimens were prepared for scanning electron microscopy to examine the surface of root canal dentine after use of each irrigant. The other 18 specimens were filled with AH plus (n = 9) or Epiphany (n=9) and subjected to a push-out test in an Instron machine. Data (in MPa) were subjected to statistical analysis by two-way anova and post-hoc Tukey-Kramer test (P < 0.05). RESULTS: AH Plus had a significantly higher bond strength (8.74 ± 2.75) than Epiphany (6.74 ± 3.97) (P < 0.05). One per cent NaOCl/17% EDTA was associated with significantly higher bond strength values (10.88 ± 3.05) than the other irrigants (P < 0.05). Seventeen per cent EDTA (8.75 ± 1.75), 24% EDTA gel (7.48 ± 3.48) and 2% CHX gel (7.89 ± 3.41) had intermediate values that were not significantly different from each other (P > 0.05). One per cent NaOCl was associated with the lowest mean values (3.70 ± 0.86) (P < 0.05). The interaction between surface treatment and sealer revealed significantly higher bond strength for 24% EDTA gel with AH Plus, 2% CHX gel with AH Plus and 1%NaOCl/17%EDTA with Epiphany (P < 0.05). CONCLUSION: Except for 1% NaOCl, the removal of smear layer with the other irrigants increased the bond strength of AH Plus to intracanal dentine. The use of 1% NaOCl for 30 min with 17% EDTA as final irrigant for 5 min increased the bond strength of Epiphany.