Comparison of the bactericidal efficacy of photodynamic therapy, 2.5% sodium hypochlorite, and 2% chlorhexidine against Enterococcous faecalis in root canals; an in vitro study

Abstract

Background:Enterococcus faecalis has been widely used as a valuable microbiological pathogen for in vitro studies due to its ability to successfully colonize the root canal in a biofilm-like style, invade dentinal tubules, and resist endodontic treatment procedures.The aim of this study was to compare the bactericidal efficacy of photodynamic therapy (PDT), 2% chlorhexidine, 2.5% NaOCl, and combination of PDT and 2.5% NaOCl against E. faecalis.Materials and Methods:Sixty single-rooted teeth had their canals contaminated with E. faecalis in brain heart infusion broth and were incubated for 48 hours.The canals were then subjected to 2% chlorhexidine, 2.5% NaOCl, PDT (red light emitting diode 625 nm+ Toludine Blue) and PDT + 2.5% NaOCl. Controls consisted of no treatment (positive control) and without inoculation of bacterium (negative control). Following treatment, the canal contents were sampled with sterile paper points.The samples were dispersed in transport medium, serially diluted, and cultured on blood agar to determine the number of colony forming units (CFU). Data were analyzed by Mann-Whitney U test at 5% significance level. The significance level for all analyses was set at P <.05.Results:Combination of PDT and 2.5% NaOCl achieved maximum reduction in recovered viable bacteria, no viable bacteria was observed after treatment of PDT + 2.5% NaOCl.Conclusion:Combination of PDT and 2.5% NaOCl simultaneously is effective in the elimination of E. faecalis from dentinal tubules under the conditions of this study.

Efficacy of antimicrobial photodynamic therapy for root canals infected with Enterococcus faecalis

“…With regard to the effect of PDT in reducing E. faecalis, some studies found it less effective than NaOCl (25,(29)(30)(31)37), others found them similarly effective (34,35), and others found that PDT had better results when associated with NaOCl (27,29,31,33,37).…”

“…Each article assessed in the present study had included a parameter for performing PDT, as summarized in Table 4. The use of intracanal fiber was not universal, since Vaziri et al (31) did not describe its use.…”

“…In the studies assessed, 60 to 220 root canals were used; most studies used 60 to 125 teeth (25)(26)(27)(28)(29)(30)(31)(32)(33)(34), and only two studies used more than 125 teeth, Bacterial reductions in the experimental groups and positive control group were significantly greater than in the negative control (P < 0.001). However, only in group 2 (Er:YAG/NaOCl/NaCL/DW) did the bacterial reduction reach 100% on the surface of the root canal walls or 100/200 mm of the dentinal tubules.…”

“…During sample preparation, root canals were sterilized and prepared before bacterial inoculation in all but three studies (26,27,33). With regard to instrumentation procedures, four studies used manual chemical-mechanical preparation with conventional files (25,28,31,34), whereas eight used rotary instrumentation with nickeltitanium files (26,27,29,30,32,33,35,37). After all samples had been sterilized and properly instrumented, bacterial inoculation was performed before the experiments.…”

“…(25,26,(28)(29)(30)(31)(32)(33)(34)(35)(36)(37), and one also used multi-rooted teeth (27). During sample preparation, root canals were sterilized and prepared before bacterial inoculation in all but three studies (26,27,33).…”