An in vitro evaluation of the antibacterial properties of three mineral trioxide aggregate (MTA) against five oral bacteria

Objective: The purpose of this study was to evaluate the antibacterial ability of three MTA (MTA-Angelus, Endocem MTA, and ProRoot MTA) against five typical oral bacteria (Streptococcus mutans, Enterococcus faecalis, Lactobacillus rhamnosus, Lactobacillus paracasei, and Porphyromonas gingivalis). Design: For disc diffusion test, each test material was placed into agar plates after inoculation of each bacterial strain. The zones of inhibition of bacterial growth were then measured. Antibacterial broth test was performed by adding the test material into the media. Colony-forming units were counted after incubation with bacteria. The data were analyzed using ANOVA and the Tukey's test. Results: Disc diffusion test showed that the antibacterial activity against S. mutans, L. rhamnosus, L. paracasei, and P. gingivalis ranked in decreasing order of MTA-Angelus > ProRoot MTA > Endocem MTA (p < 0.05). An inhibitory effect against E. faecalis was only observed in Endocem MTA. Antibacterial broth test showed that the antibacterial activity against all bacteria was Endocem MTA > MTA-Angelus > ProRoot MTA (p < 0.05). Conclusion: Discrepant results were obtained from the disc diffusion and antibacterial broth test, with MTA-Angelus and Endocem MTA being most effective, respectively. Both tests revealed that the most resistant bacteria was E. faecalis, which was not susceptible at all, except to Endocem MTA in disc diffusion test.