Comparison of the shear bond strength of composite to NEC (Novel Endodontic Cement) & MTA ( Mineral Trioxide Aggregate)

Abstract

Bond strength between restorative and pulp capping materials plays a significant rule in successes of treatment. The purpose of this study was to compare the shear bond strength of composite to NEC (Novel Endodontic Cement) or CEM (Calcium Enriched Mixture) and MTA (Mineral Trioxide Aggregate) in which RMGI (Resin Modified Glass Ionomer) was used as a control material. Materials and Method :In this study, 90 cylindrical acrylic blocks have been prepared. Each block had a central hole measuring 4mm in diameter and 2mm in depth. The specimens were prepared in three groups that were divided in two subgroups as follow: (15 specimens for each subgroup) 1) NEC (CEM) group a) etching with phosphoric acid b)without phosphoric acid etching 2) MTA group a) etching with phosphoric acid b)without phosphoric acid etching 3) RMGI group a) etching with phosphoric acid b) without phosphoric acid etching Shear bong strength test was performed using universal testing machine. A crosshead speed of 1mm/min was applied to each specimen by using a knife-edge blade until the bond between the composite with MTA, NEC(CEM) and RMGI failed. Then for calculating of shear bond strength in MPa, the force was divided on cross section of each sample. The mean and standard deviation values for each group were calculated separately. Data were analyzed by two-factor ANOVA and Tukey tests at a significant level of P<0.05. Results: There were significant differences in mean values of shear bond strength in relation to type of material (P<0.001). However, there was not any significant difference in shear bond strength of the composite to MTA and NEC(CEM) (P=0.51). Mean values of shear bond strength was not significant in relation to the type of treatment (P=0.60). Moreover, the interaction of the type of material and the type of the treatment was statistically significant (P<0.001). Conclusions: There was no significant difference in mean values of shear bond strength of composite to MTA and NEC(CEM). Shear bond strength of composite to RMGI was significantly greater than shear bond strength of composite to MTA and NEC(CEM). Use of acid etching had no significant effect on shear bond strength of composite to MTA, NEC and RMGI.