Effects of different compositions on the biocompatibility of MTA

Objectives: Mineral trioxide aggregate (MTA) has become the widely preferred material to use in contact with vital tissue to promote healing. For the consideration of esthetics, the original MTA, in gray color, has been modified by adding fluxing agent to remove dark-colored C₄AF and to develop a new tooth-colored, white MTA. Since the compositions of tooth-colored MTA are different from those of gray MTA, many researches addressed the issue of the different behaviors in biocompatibility between these two different kinds of MTA. The purpose of this study was to approach this issue by investigating the contribution of each component of MTA in its biocompatibility. Methods: Two commercialized MTA and three principle components of MTA, including C₃S, C₃A and C₄AF, produced via sintering process were used in this study. The behaviors of MRPC-1 odontoblast-like cells adhered to the tested materials were observed by SEM, and the cytotoxicities of tested materials were evaluated by MTT method. Results: The results of SEM demonstrated the MRPC-1 cells adhered to, and spread on, the surface of C₃S, gray MTA and white MTA, while the MRPC-1 cells attached to, but remained rounded, on the surface of C₃A and C₄AF when co-cultured for 2 hours. There were no significant difference of cell viability among the C₃S, M811, gray MTA, white MTA and control groups. In the C₃A and C₄AF groups, lower cell viabilities with significant differences (p<0.05) were observed at the first day of co-cultured and then the cell viability returned to the same level of control group after co-cultured for 3 days. Conclusion: C₃S, similar to gray MTA and white MTA, present the high affinity to MRPC-1 cells not only in the cell adhesion but also in cell viability, which imply that C₃S may play a key role in the biocompatibility of MTA.