An In Vitro Evaluation and Comparison of Push Out Bond Strength of MTA and MTA like materials in Acidic and Alkaline pH

AIM AND OBJECTIVE: The aim of this study was to evaluate and compare the effect of a range of alkaline, acidic and neutral pH values on the pushout bond strength and mode of failure of regular MTA (Angelus, Londrina, PR , Brazil), Endocem MTA (Endocem, Maruchi, Seoul, Korea) and MM-MTA (MM, Besançon, France). METHODOLOGY: Mid root dentin of lower first single rooted premolar tooth was horizontally sectioned into two mm thick slices. The canal spaces of each dentin slice were enlarged with Gates Glidden drills sequentially from size two to five to obtain a uniform 1.3mm diameter. The samples were divided into three groups (n=25) group I, group II, group III and the following materials were filled respectively MTA (Angelus, Londrina, PR, Brazil), Endocem MTA (Endocem, Maruchi, Seoul, Korea) and MM-MTA (MM, Besançon, France). The samples were wrapped in sterile gauze dipped in synthetic tissue fluid (STF) and divided into 5 sub-groups (Subgroup A, Subgroup B, Subgroup C, Subgroup D, and Subgroup E) corresponding to pH value of 7.4, 9.4, 10.4, 5.4 and 4.4 respectively. The samples were incubated for 3 days at 37˚C. The push out bond strength of the samples were measured using universal testing machine. The samples were examined under a scanning electron microscope to determine the nature of bond failure. RESULTS: The greatest push out bond strength of the MTA was 9.32 and the lowest was 3.60 for Endocem MTA the greatest was 8.52±0.17 and lowest was 6.12±0.13 and for MM-MTA the greatest was 8.47±0.17 and lowest was 6.02± 0.02 observed after exposure to 9.4 and 4.4 pH respectively. The statistical ranking of pushout bond strength value in neutral and alkaline pH was similar. They were as follows; MTA > Endocem MTA > MM-MTA. In acidic pH, ranking was Endocem MTA > MM-MTA > MTA. Overall statistical analysis shows Endocem MTA > MTA > MM-MTA. That is group B performed better than group A followed by group C when exposed to varying range of pH. CONCLUSION: Push out bond strength of MTA, Endocem MTA and MMMTA were influenced by different alkaline and acidic pH. The mean push out bond strength value of Endocem MTA was marginally better when compared to MTA and MM-MTA after being exposed to various range of pH values. All the experimental materials exhibited cohesive failure in alkaline and neutral pH. Whereas in acidic pH all materials showed varied mode of failure that is, Endocem MTA showed cohesive failure, MTA showed adhesive failure and MM-MTA showed mixed failure