Antimicrobial Efficacy of Various Concentrations of Chlorhexidine Against Enterococcus Faecalis Bacteria.

Introduction: Enterococcus faecalis bacteria is well-known for causing a persistent root canal infection, nevertheless its phenotypic characteristics are not widely known. Aim: To evaluate the antimicrobial efficacy of various concentrations of chlorhexidine against E. faecalis bacteria in the endodontically treated root canals. Materials and Methods: The present in-vitro study was done using E. faecalis isolates from 30 endodotic patients. Samples were taken from patients at the start of the endodontic treatment (pre treatment) and with repeated treatment (post treatment) after satisfying the inclusion criteria. E. faecalis samples were isolated from patient’s teeth which were then cultured followed by exposure to different concentrations of chlorhexidine of 0.1%, 0.2% and 2% with an incubation period of half hour, one hour and three hours respectively. Viability of E. faecalis samples were calculated with MTT assay using a standardised formula. Results: As the chlorhexidine concentration increased, the viability of E. faecalis isolates is reduced, although statistically it is not significant. With increase in incubation time from half hour to one hour, Chlorhexidine (CHX) effectiveness increased, although this trend was decreased after three hours of incubation time. Conclusion: Chlorhexidine 0.1% resulted in the largest decrease in E. faecalis viability and an incubation time of 30 minutes was effective to significantly reduce the viability of E. faecalis.