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 A(1): normal saline, Group A(2): 2.5% NaOCl, Group A(3): QMix, Group B(1): normal saline and photoactivated disinfection (PAD), Group B(2): 2.5% NaOCl and PAD, Group B(3): 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 B(2) (NaOCl with PDT), which was similar to Groups A(2) (97.6%) and B(3) (98.8%) (P < 0.0001). CONCLUSIONS: NaOCl with PDT gave maximum disinfection.