JAYPEE RESEARCH ARTICLE Antimicrobial Efficacy of Endodontic Irrigants against

Aim: To evaluate the relative antimicrobial efficacy of five different commonly used antimicrobial agents with regard to reduction in the number of Enterococcus faecalis and Escherichia coli as compared to normal saline. An agar disk diffusion in vitro method was used to test the efficacy of the root canal irrigants against these two microorganisms. The root canal irrigants used were: 5.25 % sodium hypochlorite (NaOCl), 10% citric acid, 17 % ethylene diamine tetraacetic acid (EDTA), 3% hydrogen peroxide (H2O2), 0.2 % cetrimide and normal saline (as control). Materials and methods: The sample size consisted of 120 agar plates, divided into two groups: groups I and II. Group I consisted of 60 blood agar plates for assessment of E. faecalis and group II consisted of 60 MacConkey agar plates for assessment of E. coli. On each agar plate, 6 circular cellulose nitrate paper disks were placed, on which the inoculum of the respective microorganism was poured with a micropipette. After incubation, these paper disks were removed and put in test tubes containing the particular root canal irrigants, and were vortexed for 60 seconds.The microbial count was then assessed using a microbial colony counter. Results: Results showed that in the group I (E. faecalis), maximum reduction was achieved with cetrimide, followed by NaOCl, H2O2, citric acid and then EDTA. In group II (E. coli), maximum reduction was achieved with NaOCl, followed by cetrimide, H2O2, citric acid and then EDTA