Effect of Bleaching and Ca(OH) (2) Dressing on the Bond Strength of Fiberglass Posts to Root Dentine

Objective The purpose of this study was to evaluate the effect of the intracoronary bleaching and calcium hydroxide (Ca(OH) (2) ) dressing use, on the bond strength (BS) of fiberglass posts to root dentine. Materials and Methods After root canal filling of 40 bovine incisors, a 2-mm thick cervical plug was fabricated 2 mm below the cementum–enamel junction. Seven days later, teeth were randomly distributed into four groups ( n = 10), as follows: G1 no bleaching, followed by immediate post cementation; G2 bleaching and immediate post cementation; G3 bleaching, dressing with Ca(OH) (2) for 7 days, and post cementation; and G4 bleaching, no dressing, and post cementation after 7 days. The roots were transversally cut into 1-mm thick slices to perform the push-out test (0.5 mm/min). Failure modes were assessed under scanning electron microscopy. Statistical Analysis The analysis of variance (two-way ANOVA) was performed, followed by the supplementary Tukey multiple comparison test ( a = 5%). Results No significant difference for BS was observed among groups. Considering the different root thirds, G1 had higher BS values for the cervical third in comparison with the apical one ( p < 0.05). The most frequent failure modes were adhesive between cement/dentine (G1); cohesive at the post (G2 and G3), and mixed (G4). Conclusions The BS of the fiberglass posts to root dentine was not affected by the intracoronary bleaching and the use of Ca(OH) (2) dressing.