Disinfection improvement in endodontic therapy by diode laser irradiation

The main cause for failure in Endodontics is the presence of microorganisms in root canal system. Therefore the disinfection plays fundamental rule in endodontic therapy.The laser irradiation presents properties that may improve the treatment success rates, reducing the microbial contamination. Objective:The aim of this study is evaluate the disinfection degree in depth caused by diode laser irradiation after chemomechanical procedures in vitro. Methods:Thirty extracted dental roots were sterilized by autoclave, inoculated by strain of Enterococcus faecalis ATCC 29212 during 4 weeks, and then randomly divided in 3 groups. Group 1: 10 specimens were instrumented by rotary files K3 (Sybron Endo, Orange, CA, USA) with 0.5% sodium hypochlorite and urea peroxide (Endo PTC cream, Oficinalis Farmácia de Manipulação, São Paulo, SP, Brazil). At the end irrigation by 17 % EDTA-T was performed. The specimens were irradiated intracanal by diode laser 830 nm wavelength Opus 10 (OpusDent™, Norwood, MA, USA), 3 W during 5 seconds, four times. Group 2: same procedures of group 1 without laser irradiation. Group 3: irrigation by saline solution. The specimens were divided in three thirds (apical, middle and cervical). Samples of dentin were obtained with carbide burs from inner canal walls of each third. It was totalized 180 samples that were incubated to count viable cells in mEnterococcus agar (Difco™, Becton Drive, NJ, USA The disinfection degree achieved was 99.5% in group 1, 96% in group 2 and 56% in group 3.). Results:The ANOVA statistical analysis shows better results in group with laser irradiation p<0.05, followed by group 2 and 3. Conclusions: Irradiation by diode laser in that parameters achieved disinfection improvement in endodontic therapy.