Additive effect of photoactivated disinfection on the antibacterial activity of QMix 2in1 against 6-week Enterococcus faecalis biofilms: An in vitro study

BACKGROUND Evaluation of the additive effect of photodynamic therapy (PDT) on the antibacterial activity of 2.5% sodium hypochlorite (NaOCl) and QMix against 6-week Enterococcus faecalis biofilms contaminated root canals. AIMS To establish the most suitable irrigant for eradication of 6-week E. faecalis biofilms. SETTINGS AND DESIGN In vitro study. MATERIALS AND METHODS A 6-week E. faecalis (ATCC 29212) biofilm was formed in 190 extracted teeth that were subsequently subjected to irrigation protocols as follows. Group A1: normal saline, Group A2: 2.5% NaOCl, Group A3: QMix, Group B1: normal saline and photoactivated disinfection (PAD), Group B2: 2.5% NaOCl and PAD, Group B3: QMix and PAD, Group C: no irrigation. For PAD, irradiation was done three times for 5 s each with 10 s interval on continuous mode with a 980 nm diode laser. Samples from the root canals were collected and plated onto brain heart infusion agar plates to determine the colony-forming unit/ml. STATISTICAL ANALYSIS USED One-way ANOVA, post hoc Tukey's honest significant difference test. RESULTS Maximum percentage of disinfection (99%) was seen in Group B2 (NaOCl with PDT), which was similar to Groups A2 (97.6%) and B3 (98.8%) (P < 0.0001). CONCLUSIONS NaOCl with PDT gave maximum disinfection.