Bactericidal Efficacy of Different Diode Laser Operation Modes Against Enterococcus faecalis Compared with Sodium Hypochlorite Irrigation

Abstract

Microorganisms surviving in the root canal system despite the chemomechnical preparation are the main reason for reinfection and endodontic treatment failure [1]. Among them, Enterococcus faecalis is the most commonly isolated bacterium from teeth with periapical periodontitis with or without periodontal lesions [2][3][4]. Because of its ability to form intra-and extraradicular biofilms, AbstractBackground. Microorganisms surviving in the root canal system despite the chemomechanical preparation are the main reason for reinfection and endodontic treatment failure. The introduction of laser-assisted endodontics resulted in higher success rates and less recurrent infections. Objectives. To compare the antibacterial action of diode laser irradiation (CV -1500 W, IMP -3000 W), photoactivated disinfection (PAD), and 5.25% sodium hypochlorite (NaOCl) on Enterococcus faecalis in an infected tooth model. Material and Methods. Fifty freshly extracted bovine teeth with single canals were prepared to apical size 45° ISO, autoclaved and contaminated with Enterococcus faecalis. After a 48-hour incubation the specimens were randomly divided into four treatment groups and one control group (n = 10): Group 1 was irradiated with 1500 mW (continuous wave diode laser irradiation); Group 2 was irradiated with 3000 mW (impulse diode laser irradiation, 300 ms -pulse, 300 ms -pause); Group 3 was subjected to photo-activated disinfection and Group 4 was irrigated with a 5.25% NaOCl solution for 15 min. Group 5 was rinsed with saline solution (control). After treatment, the dentin samples were collected and the number of surviving bacteria was determined by classical quantitative microbiologic evaluation. Results. The differences in the mean number of the colony forming units (CFU/mg) between all the groups analyzed were statistically significant (p < 0.001). The highest number of microorganisms was observed in the control group (52.7 x 103 CFU/mg). Both diode laser applications resulted in a significant reduction in the number of E. faecalis cells: G1 -1.4 x 103 CFU/mg, G2 -4.2 x 103 CFU/mg, whereas in the group subjected to photo-activated disinfection the extent of reduction was significantly less (G3 -42.8 x 103 CFU/mg). Conclusions. The present study demonstrates that CW and pulse diode laser applications are both suitable for root canal disinfection, but do not eradicate all bacteria (Dent. Med. Probl. 2016, 53, 2, 216-221).

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

“…Grącka-Mańkowska et al also investigated the bactericidal efficacy of different diode laser operation modes against Enterococcus faecalis under in vitro conditions. 30 Bovine teeth were infected with the bacterial strain and a high-power diode laser was applied with the parameters of 1.5 W CV and 3 W impulse irradiation. In both experimental groups, the mean number of bacterial cells was reduced: in 1.5 W group by 97%, and in 3 W by 93%.…”

The Effect of High-Power Lasers on Root Canal Disinfection: A Systematic Review

“…14,[16][17][18] However, some studies have reported that merely irradiating the root canal with a diode laser reduces the bacterial load more than traditional irrigation methods. 13,[19][20][21][22][23][24][25] To achieve higher levels of disinfection, the diode laser has been used coincide with irrigation with distilled water, 26,27 ozonated water, 26 saline, 12,22 chlorhexidine, 27 silver nanoparticles, 27 and another laser application. 28 Additionally, the diode laser has been used in the LAI technique with NaOCl, 13,29,30 and most of these studies have reported that LAI is a more potent tactic to disinfect root canals.…”