Micro-Shear Bond Strength between Mineral Trioxide Aggregate Paste Fast Setting and Different Composite Materials

This study aimed to estimate the micro-shear bond strength between mineral trioxide aggregate (MTA) “fast setting” premix paste (ENDOCEMTM, Maruchi, Wonju, Korea) and different composite materials (EverXTM Flow GC, Japan and Bulk FillTM Flowable A2, 3M ESPE, USA). A total of 40 resinous molds were prepared for application of Premix MTA paste, then the restorative material was applied with different times of restoration. The total samples were divided into 2 groups according to the time of application of restorative materials (group A after 5 min and group B after 24 h), then each group was divided into 2 subgroups according to the restorative materials used (A1 and B1 subgroups with EverXTM Flow, GC, Japan, and A2 and B2 subgroups with Bulk FillTM Flowable A2, 3M ESPE, USA). The mean micro-shear bond strength increased with time elapsed between the application of the MTA and the placement of the restorative materials. After 24 h, Subgroup B2 had the highest bond strength, followed by Subgroup B1. After 5 min, Subgroup A1 had a higher bond strength than Subgroup A2. The properties of the calcium-silicate- materials (CSMs) improved after waiting 24 hrs, which contradicts the manufacturer’s recommendation to allow only 3 min for the initial setting. Incorporating the 10-MDP monomer in the dental adhesive enhanced integration at the interface between the adhesive and the restorative resin, as reflected in the mixed mode of fracturing.