ABSTRACT
BACKGROUND: The aim of this study was to evaluate the antimicrobial activity of Mineral Trioxide Aggregate (MTA) and Calcium Enrich Mixture) CEM (mixed with different concentrations of chlorhexidine (CHX). MATERIALS AND METHODS: Cements used in this in vitro study included Gray proRoot MTA and CEM with the microorganisms being entrococcus faecalis, streptococcus muntas, Candida albicans, Actinomyces, Escherichia coli, and a mixture of these microorganisms. CHX was used in the form of liquid at 0.2%, 2%, and 0.12% concentrations. Contact dilution and colony count method was used to evaluate the antibacterial activity of these cements. After 0, 24, 48, 72, and 96-hour intervals, we cultured the samples on blood agar medium. Colonies were counted after incubation at 37°. Data were statistically analyzed by a Kruskal-Wallis test to compare the antimicrobial activity of MTA and CEM. RESULTS: All concentrations of CHX were mixed with MTA and the CEM had antibacterial activities on all microorganisms' strains except for the Enterococcus faecalis and the mixture group. MTA had better antibacterial activity than the CEM, but this difference was not significant (P = 0.13). The mixing of MTA and the CEM with CHX significantly increased the antibacterial properties of both cements (P < 0.03). There was no statistically significant difference between the different concentrations of CHX. The antibacterial activity of the materials increased through time. CONCLUSION: The mixture of MTA and CEM with different concentration of CHX significantly increased the antibacterial activity.
ABSTRACT
Using the agar diffusion method, we conducted an in vitro study to evaluate the antimicrobial activity of mineral trioxide aggregate (MTA), new endodontic cement (NEC) and Portland cement at different concentrations against five different microorganisms. A base layer was made using Muller-Hinton agar for Escherichia coli (ATCC 10538) and Candida (ATCC 10231). For Actinomyces viscosus (ATCC 15987), Enterococcus faecalis (ATCC 10541) and Streptococcus mutans (ATCC 25175) blood agar medium was used. Wells were formed by removing the agar, and the materials were placed in the well immediately after manipulation. The plates were kept at room temperature for 2 h for prediffusion, and then incubated at 37 degrees C for 72 h. The inhibition zones were then measured. The data were analyzed using ANOVA and the Tukey test to compare the differences among the three cements at different concentrations. The positive controls showed bacterial growth, while the negative controls showed no bacterial growth. All materials showed antimicrobial activity against the tested strains except for Enterococcus faecalis. NEC created larger inhibition zones than MTA and Portland cement. This difference was significant for Portland cement (P < 0.05), but not for MTA (P > 0.05). Among the examined microorganisms, the largest inhibition zone was observed for Actinomyces group (P < 0.05). The antimicrobial activity of the materials increased with time and concentration (P < 0.05). It was concluded that NEC is a potent inhibitor of microorganism growth.
