Evaluation and comparison between the bactericidal effect of diode laser irradiation (970 nm) and silver nanoparticles on Enterococcus faecalis bacterial strain (an in vitro study)

Abstract

Abstract Background/Aims Today, the using of diode lasers in dentistry has made a significant progress; it increased the speed of treatment, decreased the time of healing, and showed a bactericidal effect. The thermal effects should be considered in root canal treatment by laser, as the temperature rises to critical levels, causing tissues damage and any thermal change occurs after laser irradiation. The temperature can rise up to 10 °C above the body temperature for less than 2–3 min without damaging the periodontal tissue or burring the tooth structure by using cooling. Antibacterial properties of silver nanoparticles (Ag-NPs) were reducing Gram-positive and Gram-negative bacterial growth, due to a larger surface to volume ratio of nanoparticles. The goal of this study is to evaluate the bactericidal effect of diode laser irradiation (970 nm), the silver nanoparticles in root canals infected by Enterococcus faecalis bacteria, and the thermal change that occurs after laser application. Materials and methods Forty-five extracted single-rooted human maxillary anterior teeth were collected and used as a container for the test. The samples are inoculated by Enterococcus faecalis bacterial strain and randomly divided into three groups: group I (control) (n = 15), group II (Enterococcus faecalis bacteria and silver nanoparticles) (n = 15), and group III (Enterococcus faecalis bacteria and diode laser) (n = 15). The laser group was divided into subgroups according to the time of laser irradiation (20 s, 30 s, and 40 s). Results There was a significant difference between the treated groups, in which the laser group showed a high bactericidal effect than the other groups at the time of radiation 40 s, without damaging the tooth structure or periodontal ligament. Conclusion Diode laser with proper parameters is used as an adjunctive endodontic disinfection modality due to its antibacterial effect with a temperature tolerated by periodontal tissues with safety limit.