Background The aim of this study was to evaluate the effects of surface treatments with 1% peracetic acid (PA), solution containing 17% EDTA (SmearClear, Kerr Endodontics), solution containing a combination of 17% EDTA with 2% chlorhexidine (QMix, Dentsply Sirona) on the post-space root dentin compared to 2.5% sodium hypochlorite (NaOCl) on bond strength and resin tags length in dentin. Material and Methods Forty human-canine roots were endodontically treated and the post space was prepared. The specimens were randomised into four groups (n = 10): control – irrigation with 2.5% NaOCl solution, PA – irrigation with 1% PA, SmearClear – irrigation with SmearClear solution, and QMix – irrigation with QMix solution. The fibre posts were cemented using a self-adhesive resin system (Relyx U200, 3M ESPE). After six months, the specimens were cross-sectioned and subjected to push-out and confocal laser microscopy tests. One-way ANOVA and Tukey’s tests were used to analyse the data (α= 0.05). Results PA and QMix presented the highest bond strength values compared to the other groups ( p < 0.05). There was no significant difference between the resin tags length in dentin by the groups ( p = 0.75). Conclusions Irrigation of the post space with 1% PA and QMix showed a positive clinical impact on the adhesion between the fiber post and root dentin. However, these materials had no influence on resin tags length in dentin by self-adhesive resin cement. Key words: Fiber post, adhesive cementation, self-adhesive resin cement, root dentin, irrigating solutions.

No abstract