Abstract:

Objective To evaluate the antimicrobial effects of different irrigants on the mixed infection of Enterococcus faecalis and Candida albicans in standard root canal models. Methods The mixed biofilm of Enterococcus faecalis and Candida albicans was inoculated into the standard root canal and cultured for 28 days. Canals were washed with 2.5% NaClO or 2% CHX and prepared with ProTaper NEXT, and normal saline was used as a blank control. After chemomechanical preparation, microbial reduction rates were calculated using colony-forming units(CFUs)counting methods; the depths of microbial inhibition in dentinal tubules were examined using a confocal laser scanning electron microscope(CLSM). Results The clearance rates of Enterococcus faecalis and Candida albicans in mixed infection root canals in 2.5% NaClO and 2% CHX groups were higher than those in normal saline group(P<0.05). CLSM observation showed that the inhibition depths of 2.5% NaClO group were significantly higher than those of 2% CHX group(P<0.05), while 2% CHX only inhibited microbes on the superficial dentine. Conclusion 2.5% NaClO exhibits better cleaning effect than 2% CHX on the mixed infection of Enterococcus faecalis and Candida albicans, which can be widely used in clinic.

Key words: root canal irrigation, Enterococcus faecalis, Candida albicans, NaClO, CHX