The Effect of Chlorhexidine on Push-out Bond Strength of Mineral Trioxide Aggregate

Trioxide Aggregate (MTA) has been widely used in root canal therapy. MTA has been mixed with chlorhexidine to increase its antimicrobial effect. The aim of this study was to evaluate the effect of chlorhexidine (2%) on push-out bond strength of Mineral Trioxide Aggregate (MTA). Sixty dentin disks with a thickness of 1.5 ± 0.2 mm and lumen size of 1.3 mm were prepared. Dentin disks were randomly divided into four groups (n = 15), and their lumens were filled with MTA mixed with distilled water (groups 1 and 3) or with chlorhexidine 2% (groups 2 and 4). Specimens were incubated at 37°C for 3 days (groups 1 and 2) or 21 days (groups 3 and 4). Bond strengths of the MTA-treated dentin surfaces were evaluated using a universal testing machine, and bond failure on the disks was examined by light microscope. Data was analyzed using Kruskal-Wallis H test (P = 0.976). There were no statistically significant differences between all the experimental groups. The mode of bond failure was predominantly mixed for distilled water groups and cohesive for CHX groups. This study suggested that chlorhexidine had no negative effect on the bond strengths of MTA-treated dentin.