In vitro evaluation of the antimicrobial efficacy of 5% Doxycycline, 0.2% Chlorhexidine gluconate and 2.5% Sodium hypochlorite used alone or in combinations against Enterococcus faecalis

The present in vitro study was undertaken to evaluate the antimicrobial efficacy of 5% doxycycline, 0.2% chlorhexidine gluconate and 2.5% sodium hypochlorite when used alone or in combinations against nterococcus faecalis. Agar diffusion test was done to evaluate the antimicrobial efficacy of the various intracanal irrigants. Enterococcus faecalis (ATCC 29212) was used as a test organism. The inoculum of E. faecalis was streaked on the agar plates. Using a punch, wells each measuring 6mm in diameter and 4mm depth were made and 50 μl of the experimental irrigant was pipetted into each well. A total of 200 wells were made, 40 for each group and the plates were placed in a carbon dioxide incubator at 37° C for 48 hours. The zones of inhibition were measured using a mm scale and the results statistically analyzed using ANOVA test and Tukeys HSD. The zones of inhibition recorded were 19.90, 14.60, 24.75, 25.58, 26.86 mm for Group A (chlorhexidine gluconate), Group B (sodium hypochlorite), Group C (doxycycline), Group D (combination of doxycycline and sodium hypochlorite) and Group E (combination of doxycycline and hlorhexidine gluconate) respectively. Within the limitations of this experiment, the results of the present study concluded that a combination of 5% doxycycline and 0.2% chlorhexidine is the choice of irrigant against E.faecalis.