OR10 - Efficacy of ER:YAG Laser in Reducing Bacterial Infection in Root Canal Treatment

Abstract: Objective: To evaluate in-vitro the efficiency of new laser machine (EdgeLase,EdgeEndo®) in elimination of a well established single-species biofilm during chemo-mechanical preparation of root canal treatment. Methodology: Seventeen intact extracted anterior teeth with single canal were included. Intracanal biofilms were developed using three models: a)novel model b)whole tooth submerged in media model and c)split tooth submerged in media model. For preparation of the single-species biofilm, we grew E.faecalis (OG1RF) in 37°C with 5% CO2 to an optical density of 0.8 which corresponds to a cell density of 109 measured with a spectrophotometer at 600nm wavelength. The bacterial suspensions were serially diluted and an inoculum size of 105 of E. faecalis cells was used in each model. At day 21, biofilms were harvested and analyzed using SEM imaging and culture. Experimental groups included standard irrigation protocol (SIP) (3% NaOCl,17%EDTA) (n=6), SIP plus 30 seconds of laser activation (20mJ,15Hz,50mS,30S) and laser activation alone using PBS(n=6). Negative controls had PBS irrigation alone(n=5). Statistical analysis was performed using ANOVA and a P-value< 0.05 was considered significant. Results:SIP plus 30 seconds of laser activation showed greater bacterial reduction, demonstrated by fewer CFU/ml on the agar plates, as well as cleaner dentinal tubules in SEM images. Results obtained with laser activation alone were similar to those obtained in the negative control group for culture and SEM analysis.Conclusion: The use of adjunctive laser application to activate SIP increased the reduction of E. faecalis biofilms, whereas the laser application alone, in the absence of an active chemical irrigant did not.