Elimination of the microorganisms in root canals is one of the most important stages for a successful endodontic treatment. Several techniques and agents have been tested to find an alternative option to sodium hypochloride for effective root canal disinfection. The aim of this in vitro study was to evaluate the antimicrobial efficacy of gaseous ozone and ozonated water in order to establish their potential as endodontic root canal disinfectant.
Eighty teeth with single canal were prepared and inoculated with Enterococcus faecalis suspension and incubated for a week. The contaminated root canals were exposed to irrigating solutions including gaseous ozone (44 µg ml-1) with ozonated water (5 µg ml-1), 5.25% sodium hypochlorite, 2% chlorhexidine for 3 min. Samples from the root canals were collected by paper points, before and after irrigation. The bacterial count was analyzed by serial decimal dilutions and the percentage of surviving microorganisms was statistically assessed.
There was a significant reduction in the bacterial count after all treatments (P < 0.001) while having greater antimicrobial reduction was observed on samples of NaOCl irrigation. There was no significant difference between gaseous ozone and gaseous ozone + ozonated water groups.
Under limitations of this study, it could be concluded that the gaseous ozone, as an irrigant agent, significantly reduced the number of E. faecalis in root canals but was not able to eliminate it. However, ozonated water was insufficient to increase the antibacterial effectiveness of gaseous ozone.