An in vitro evaluation of the antimicrobial effectiveness of different irrigation solutions and light activated disinfection systems on Enterococcus faecalis biofilm

The aim of this study was to evaluate the effectiveness of % 5,25 Sodium hypochloride, % 2 Chlorhexidine gluconate, % 100 Octenidine hydrochloride and two 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.In this study, E. faecalis biofilm was grown on the standard hydroxyapatite discs, which have a 9.7 mm diameter and 1.5 mm width, for 4 weeks. At the end of the 4 weeks, the discs whose surfaces were covered by E. faecalis biofilm were kept in the irrigation solutions for 1 and 5 minutes. Discs in the Fotosan group, a light activated disinfection system, immersed in the photosensitizer agent, and activated by LED light for 30 seconds according to the manufacturer?s instructions. In the other group, discs were immersed in methylene blue, and activated by diode laser for 30 seconds. In the culture method, following antimicrobial exposure, discs were kept in ultrasonic water bath for 1 minute in order to remove remaining adherent bacteria from the discs. Aliquots from the bacterial suspension were added on TSA, and incubated for 24 hours at 37 °C. After incubation, bacteria colonies grown on the culture were counted. Dead (red) and live (green) bacteria on the discs were identified by coloring the discs with florescence dyes in order to make an evaluation in the laser scanning confocal microscope. Dead cells / total cells ratio was calculated.According to the data achieved, in both of the methods and application times, all of the tested irrigation solutions were found more effective than light activated disinfection systems except the control group Saline. 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. In both of the methods and application times, no difference was found between the tested light activated disinfection systems. In the culture method, no difference was found between Fotosan and Saline statistically. Within the results of the laser scanning confocal microscope analysis no statistical difference was found between Fotosan group and Saline group in application time of 1 minute. No statistical difference was found between Diode laser group and Saline group in application time of 5 minute. In the culture method, no statistical difference was observed between application times of 1 and 5 minutes in all of the other groups except Fotosan. In the Fotosan group, 5 minute was found more effective than 1 minute statistically. In the conclusions of the laser scanning confocal microscope analysis no statistical difference was observed in application times in all of the groups. According to the data achieved, a correlation was observed between two methods.