Effect of Acidic Environment on Dislocation Resistance of Endosequence Root Repair Material and Mineral Trioxide Aggregate

Objective: the aim of this study was to compare the effect of an acidic environment on dislocation resistance (push-out bond strength) of endosequence root repair material (errm putty and errm paste), a new bioceramic-based material, to that of mineral tri-oxide aggregate (mta).materials and methods: one-hundred twenty root dentin slices with standardized canal spaces were divided into 6 groups (n = 20 each) and filled with tooth-colored proroot mta (groups 1 and 2), errm putty (groups 3 and 4), or errm paste (groups 5 and 6). the specimens of groups 1, 3, and 5 were exposed to phosphate buffered saline (pbs) so-lution (ph=7.4) and those of groups 2, 4, and 6 were exposed to butyric acid (ph= 4.4). the specimens were then incubated for 4 days at 37°c. the push-out bond strength was then measured using a universal testing machine. failure modes after the push-out test were examined under a light microscope at ×40 magnification. the data for dislocation resistance were analyzed using the t-test and one-way analysis of variance.results: in pbs environment (ph=7.4), there were no significant differences among ma-terials (p=0.30); but the mean push-out bond strength of errm putty was significantly higher than that of other materials in an acidic environment (p<0.001). push-out bond strength of mta and errm paste decreased after exposure to an acidic environment; whereas errm putty was not affected by acidic ph. the bond failure mode was predomi-nantly cohesive for all groups except for mta in an acidic environment; which showed mixed bond failure in most of the specimens.conclusion: the force needed for dislocation of mta and errm paste was significantly lower in samples stored in acidic ph; however, push-out bond strength of errm putty was not influenced by acidity.