Materials and method: A total of 120 extracted single-rooted teeth were infected for 21 days with E. faecalis after instrumentation with Pro Taper system. Before irrigation procedure, dentinal shavings were collected in 1 ml of sterile broth and incubated. The optical density of each broth was measured using digital colorimeter and initial readings were recorded. Samples were then divided into five groups of 24 teeth in each group– Group A: Sodium hypochlorite irrigation, Group B: EDTA irrigation, Group C: Chitosan irrigation, Group D: Chlorhexidine irrigation, Group E: Saline irrigation. Each group was further divided into three subgroups – (I) Room temperature of irrigant (II) Warm temperature of irrigant (III) Intracanal heating of irrigant. After irrigation, dentinal shavings were collected and optical density recorded. The values were analysed statistically with Student’s t test and analysis of variance followed by Post-Hoc Bonferroni’s correction test; p-value < 0.05 was considered to be statistically significant.

Results: The post irrigation optical densities in all the groups were significantly lower than pre irrigation values. Sodium hypochlorite and Chlorhexidine demonstrated better antimicrobial efficacy followed by Chitosan and EDTA, whereas the least efficacy was shown by Saline which was the control group. Differences in optical density using different irrigants were found to be higher by intracanal heating of irrigants followed by warm irrigation and room temperature irrigation (p<0.0001).

Conclusion: Chitosan exhibited effective antimicrobial effect similar to Chlorhexidine and Sodium Hypochlorite. Intracanal heating was most effective for elimination of E.faecalis followed by warm irrigation as compared to that of room temperature of the irrigant.