The aim of this study is to analyze the effects of different endodontic irrigants and adhesive systems on the resin bond strength of fiber post cementation. In total, 144 single-rooted, unrestored human teeth were endodontically treated and randomly divided into 12 groups according to four endodontic irrigants (distilled water as control; EDTA 17%; NaOCl 5%; chlorhexidine digluconate 2%) and three different adhesive/resin cement systems (etch-and-rinse: orthophosphoric acid, Parabond® A+B/Paracore®; self-etch: ParaBond® Non-Rinse Conditioner, Parabond® A+B/Paracore®; Universal: ClearfilTM Universal Bond/ClearfilTM DC Core Plus). Forty-eight hours after post cementation, ten teeth from each group were cross-sectioned into three discs (cervical, middle and apical regions). Thirty specimens of each group (n = 30) were submitted to a push-out test at a crosshead speed of 1 mm/min. The remaining two teeth of each group were sectioned in the same manner, and the resin-dentin interface was evaluated using scanning electron microscopy (SEM). The results were statistically analyzed with the ANOVA test and Tukey's test (p < 0,01). The adhesive protocols and post space region showed no significant effect on bond strength (p > 0.01). The combination of NaOCl 5% and ClearfilTM Universal Bond reduced the adhesive strength (p < 0.01). The NaOCl 5%, in relation to other irrigants, significantly decreased the push-out bond strength.
Keywords: EDTA; bond strength; chlorhexidine; dental adhesive; dentin; fiber post; hybrid layer; push-out; sodium hypochlorite.