Comparative evaluation of antimicrobial efficacy of MTAD, DMSA (Di Mercaptosuccinic acid), sodium hypochlorite (NaOCl) and chlorhexidine against E. faecalis: An ex-vivo study

Aim: The aim of this study was to compare the anti-microbial efficacy of four root canal irrigants, MTAD, 10% Di Mercaptosuccinic acid (DMSA), 5.25% Sodium Hypochlorite and 2% Chlorhexidine gluconate against Enterococcus Faecalis. Materials & Methods: 75 extracted single rooted teeth with single canal were selected for this study. Conventional access preparations were made and the canals were instrumented 1 mm beyond the apical foramen with K-files up to size 50. The teeth were autoclaved. Pure culture of E. Faecalis was grown in brain heart infusion broth and was set to 4 Mac Farland's standard. 5 micro-litre of the broth was used to infect each of the root canal. The teeth were then divided into 5 groups (n=15) according to the irrigant delivered; group 1 was irrigated with MTAD, group 2 with 10% DMSA, group 3 with 5.25% Sodium Hypochlorite, group 4 with 2% Chlorhexidine gluconate and group 5 was irrigated with Normal saline (control group). Samples were collected from the root canals, after 5 minutes and 48 hours of irrigation, with help of absorbent paper points and were immediately transferred to test tubes containing brain heart infusion broth and incubated. Occurrence of broth turbidity was indicative of the viable bacteria remaining in the root canal. The test tubes where turbidity occurred were inoculated onto chocolate Agar plates to check for E. Faecalis. Results were analyzed statistically using Chi-Square test and Mann-Whitney test (p<0.05). Results: Viable bacteria were found in all the canals of the control and 10% DMSA group. No viable bacteria were remaining in canals after 5 min of irrigation with MTAD and CHX whereas 67% of the root canals irrigated with NaOCl showed growth. After 48 hours of irrigation only teeth irrigated with CHX were free from viable bacteria. Conclusion: 2% Chlorhexidine has a superior anti-microbial and residual anti-microbial activity against E. Faecalis compared to all the irrigants tested.