Mineral trioxide aggregate(MTA) and Portland cement(PC) contain calcium oxide, which reacts with water to form calcium hydroxide and producesa highly alkaline environment that inhibits bacterial growth. Compared with white PC(WPC) and MTA, gray Portland cement(GPC) has high concentrations of harmful heavy metals, namely arsenic, chromium, and lead. The solubility of root-canal filling affects itsability to close. The overall apical closure performances of MTA and PC are relatively similar. Good oral materials should have appropriate setting times. Addition of calcium chloride or calcium formate to MTA and PC shortens their setting time. The particle size of the material also affects its closure, setting time, compressive strength, and abrasion resistance. The average particle size of WPC is greater than that of MTA; however, the compressive strength of the former is lower than that of the latter. When mixed with gold powder, the compressive strength of WPC is similar to that of MTA. MTA and PC are non-toxic and genotoxic, and their toxicities to Chinese hamster ovary cells showno significant difference. Moreover, MTA and PC exhibit antibacterial activities toward Micrococcus luteus, Staphylococcus aureus, Escherichia coli, and other microorganisms. MTA and PC can promote hard tissue mineralization, which can leadto crown discolorations; PC results in lighter colors compared with those observed from MTA. Applications of MTA are limited by its long setting time, tooth discoloration, high-cost, and difficultyof removal. Thus, PC can be an economical alternative to MTA for dental restoration. The long-term effects of this material, however, are still uncertain and require longer assessments.
