Effect of 2% chlorhexidine digluconate on bond strength of a glass-fibre post to root dentine

Aim To assess the immediate influence of dentine bonding systems (DBS) associated with 2% chlorhexidine digluconate (CHX) on glass‐fibre post‐bond strength to root dentine, in terms of coronal, middle and apical thirds. Methodology Sixty bovine roots were root filled and randomly assigned to 1 of 6 groups (n = 10): SBMP (3‐step etch‐and‐rinse system, Scotchbond Multi‐Purpose), SB (2‐step etch‐and‐rinse system, Single Bond 2), SE (2‐step self‐etching system, Clearfil SE Bond) and SBMP‐CHX, SB‐CHX and SE‐CHX, respectively, associated with CHX. For all groups, a glass‐fibre post was luted with a dual‐cure resin cement, RelyX ARC. After 7‐day storage, specimens were subjected to the push‐out test. Failure modes were analysed under optical microscopy (40x). Bond strength values were statistically analysed by two‐way anova and Bonferroni tests (P 0.05), except for the SE‐CHX, which presented lower values for the apical third (P 0.05). Conclusions The performance of the dentine bonding systems was material dependent. CHX did not improve immediate bond strength; however, CHX negatively affected the bond strength of the self‐etching system, especially in the third apical.