Effect of root canal sealers on bond strength of fibreglass posts cemented with self‐adhesive resin cements

Abstract

This study evaluated the effects of different root canal sealers on the bond strength of a fibreglass post cemented with self-adhesive resin cements. The root canals of 50 extracted maxillary single-rooted canine teeth were prepared with the crown-down technique and randomly divided into five groups according to the sealer used: group 1: control group, gutta-percha points only (no sealer); group 2: AH Plus (resin-based sealer); group 3: self-etch Epiphany (resin-based sealer); group 4: Sealer 26 (calcium hydroxide-based sealer); and group 5: Endomethasone (zinc oxide eugenol-based sealer). The root canals were filled with gutta-percha, the cold lateral compaction technique, except for group 3 where Resilon was used. Post spaces were prepared, and fibreglass posts were cemented with the self-adhesive cement RelyX Unicem. Bonded specimens were sectioned into 1-mm-thick slabs, and a push-out test was performed in a universal machine. Failure modes were observed and classified into five types: (i) adhesive between the post and resin cement; (ii) mixed, with resin cement covering 0-50% of the post diameter; (iii) mixed, with resin cement covering 50-100% of the post surface; (iv) adhesive between resin cement and root canal; and (v) cohesive in dentine. Data of bond strength were submitted to anova and Tukey test (α = 0.05). No significant difference was detected between control group, AH Plus, Epiphany and Sealer 26 (P > 0.05). The Endomethasone group had significantly lower bond strength values than the other sealers (P < 0.05). The prevalence of mixed fractures and adhesive cement-dentine failure was verified in the eugenol-containing sealer group; in the control group, the resin-based and calcium hydroxide-based sealer groups, the predominant mode of failure was the mixed type. Endomethasone interfered negatively with the bond to root dentine; however, AH Plus, Epiphany and Sealer 26 did not interfere in the bond strength of a fibreglass post cemented with self-adhesive resin cements.