Effects of  Different Antimicrobial Disinfection Systems on Enteroccoccus faecalis Biofilms

Objectives : The aim of this study was to evaluate the antibacterial effectiveness of % 5.25 Sodium hypochloride, % 2 Chlorhexidine gluconate, % 100 Octenidine  hydrochloride and 2 different  light activated disinfection systems (Fotosan and methylene blue & diode laser)  on E. faecalis biofilm, by using the bacteria culture method and laser scanning  confocal microscope (LSCM).

Methods: Biofilms of E. faecalis were grown on the standard hydroxyapatite discs, which have a 9.7 mm diameter and 1.5 mm width, for 4 weeks. After 4 weeks, the E. faecalis biofilms formed on hydroxyapatite discs were subjected to test solutions for 1 and 5 minutes. In the light activated disinfection system groups, discs were immersed in the fotosensitizer agents, and activated by light sources for 30 seconds in according to the manufacturer's instructions. After treatments, ten fold serial dilutions were generated and aliquots from each dilution were added on TSA. The plates were incubated for 24 hours at 37 °C and colony-forming units were calculated. Besides, the ratio of dead bacteria to all bacteria in biofilms was analyzed by LSCM.    

Results: According to the data achieved, a correlation was observed between two methods. No difference was found between tested light activated disinfection systems. Except the control group Saline, all of the tested irrigation solutions were found more effective than light activated disinfection systems. No statistical difference was observed between % 5,25 NaOCl and %100 Octenidine hydrochloride. % 2 CHX being found less effective than % 5,25 NaOCl, any statistical difference was observed between % 2 CHX and % 100 Octenidine hydrochloride.

Conclusions: These in vitro results suggest that light activated disinfection systems are not alternative antimicrobial treatments. They may not exert a significant supplemental effect to irrigation solutions. % 5,25 NaOCl is the most effective irrigation solution to eradicate E. faecalis biofilms.