The antibacterial properties and biocompatibility of carbonated hydroxyapatite as a pulp capping agent

Objective: The present study evaluated the antibacterial efficacy and biocompatibility of carbonated hydroxyapatite (CHA) compared to mineral trioxide aggregate (MTA).Methods: CHA was synthesized at 0.05, 0.1, and 0.5 M concentrations. The minimal inhibitory concentration (MIC) of CHA and MTA were measured against Streptococcus mutans, Enterococcus faecalis, and Candida albicans. Afterwards, 1x107 CFU/mL of each microorganism was exposed to the concentration corresponding to the MIC of each material and the bacterial colony count was measured. The survival rate, hatching rate, heart rate, and morphology of zebrafish embryos were evaluated when exposed to CHA or MTA (n=20 embryos per group) Results: For S. mutans, the lowest MIC levels were found in the 0.05 and 0.5 CHA groups. The MIC value of all CHA concentrations against E. faecalis was 25 µg/ml. The lowest MIC against C. albicans was noted in the 0.1 CHA group. At the respective MIC levels, the 0.5 CHA showed the lowest colony count for S. mutans, which was significantly lower than that of MTA and 0.1 CHA groups (P<0.05). For E. faecalis, the 0.1 CHA and MTA groups had significantly lower colony count than the 0.05 CHA group (P<0.05). Regarding C. albicans, the 0.1 CHA had the lowest colony count, significantly lower than the 0.05 CHA group (P<0.05). Zebrafish embryos showed the lowest survival, hatching, and heart rates when exposed to MTA (P< 0.05).Conclusions: The 0.1 and 0.5 CHA concentrations showed a favorable antibacterial efficacy against various oral microorganisms and better biocompatibility than MTA.