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 Conclusions: NaOCl with PDT gave maximum disinfection.