the effect of chlorhexidine on the push-out bond strength of calcium-enriched mixture cement

introduction: the aim of this in vitro study was to evaluate the effect of 2% chlorhexidine (chx) on the push-out bond strength (bs) of calcium-enriched mixture (cem) cement. methods and materials: root-dentin slices from 60 single-rooted human teeth with the lumen diameter of 1.3 mm were used. the samples were randomly divided into 4 groups ( n =15), and their lumens were filled with cem cement mixed with either its specific provided liquid (groups 1 and 3) or 2% chx (groups 2 and 4). the specimens were incubated at 37 ° c for 3 days (groups 1 and 2) and 21 days (groups 3 and 4). the push-out bs were measured using a universal testing machine. the slices were examined under a light microscope at 40× magnification to determine the nature of bond failure. the data were analyzed using the two-way anova. for subgroup analysis the student t-test was applied. the level of significance was set at 0.05. results: after three days, there was no significant difference between groups 1 and 2 ( p =0.892). in the 21-day specimens the bs in group 3 (cem) was significantly greater than group 4 (cem+chx) ( p =0.009). there was no significant difference in bs between 3 and 21-day samples in groups 2 and 4 (cem+chx) ( p =0.44). however, the mean bs after 21 days was significantly greater compared to 3-day samples in groups 1 and 3 ( p =0.015). the bond failure in all groups was predominantly of cohesive type. conclusion: mixing of cem with 2% chx had an adversely affected the bond strength of this cement.