Effects of 980 nm diode laser application protocols on the reduction of Enterococcus faecalis intracanal biofilm: An in vitro study

Abstract

© 2017 by Wroclaw Medical University and Polish Dental Society. Background. Enterococcus faecalis is associated with a great number of refractory endodontic infections. There is a need to investigate antibacterial properties of laser radiation and create a new alternative technique for root canal disinfection. Objectives. The purpose of the study was to investigate the effectiveness of a single and repeated high-power diode laser irradiation protocol on the elimination of a 1-week-old Enterococcus faecalis intracanal biofilm. Material and methods. A total of 46 single-rooted human teeth were subjected to the in vitro observation. They were chemomechanically prepared, sterilized, infected with a clinically isolated strain of Enterococcus faecalis and subjected to 1-week incubation under microaerobic conditions. The experimental procedures included: a single cycle of 980 nm laser diode irradiation, second application of the same laser protocol, 5.25% NaOCl irrigation, and 2 control groups. Quantitative evaluation of bacterial colonies in the root canals was performed based on the CFU/mL method, after different sterilization methods had been applied. Results. A statistically significant reduction in the number of intracanal Enterococcus faecalis colonies, after a single and repeated 980 nm diode laser application, was confirmed. The first cycle of laser irradiation eliminated 52.5% of E. faecalis colonies, whereas the second application increased disinfection effectiveness to 87.6%. Conclusions. The 980 nm diode laser demonstrated statistically significant antibacterial activity. High-power diode laser treatment might be considered as an adjunctive to conventional chemomechanical endodontic treatment.