An ex vivo comparative study determining the bactericidal activity of 3 different irrigants against Enterococcus faecalis

Aim: To evaluate and compare the antimicrobial activity of 3% sodium hypochlorite, 2% chlorhexidine gluconate and freshclor (stabilized chlorine dioxide) against Enterococcus faecalis. Materials and Method: 3% sodium hypochlorite, 2% chlorhexidine gluconate and freshclor were the materials used in this study. Agar diffusion test: E. faecalis isolated from root canal infected samples were included in the study. Cultures were maintained on brain heart infusion (BHI) broth and agar. Cultures grown overnight at 37 degree Celsius in BHI broth on a rotary shaker 150 rpm and bacterial growth checked by changes in turbidy at 24 hours. BHI agar plates were prepared and cultures (200ul) were spread onto agar plates. Wells of 6mm diameter were made in the agar surfaces. Samples were divided into 3 groups. Group 1- 3% Sodium hypochlorite, Group 2- 2% Chlorhexidine gluconate, Group 3- Freshclor(stabilized chlorine dioxide), Control-distilled water. 50ul each was added to the respective wells and the plates were incubated for 24 hours in an incubator. After incubation period, plates were removed and zones of inhibition were recorded. Experiment was performed 3 times and mean zone of inhibition was recorded in mm. Statistical Analysis: The data were analysed using One-way analysis of variance & Tukeys post hoc test. Results: Significant difference between chlorhexidine and stabilized chlorine dioxide was found as well as between sodium hypochlorite and stabilized chlorine dioxide. Conclusion: 0.1% stabilised chlorine dioxide had bactericidal activity against E. faecalis, but less than the other two groups. As chlorine dioxide has minimal toxicity and tissue dissolving property as well, it can be considered as an alternative endodontic irrigant at higher concentration.