Identification and quantification of Enterococcus faecalis by real-time quantitative pcr during endodontic treatment.

AIM: To evaluate the quantification of Enterococcus faecalis using quantitative polymerase chain reaction (qPCR) and culture techniques following different root canal irrigation protocols in refractory endodontic cases. MATERIALS AND METHODS: Fifty refractory endodontic cases were randomly allocated into five experimental groups according to the irrigant and activation method used: Group I, saline irrigation; Group II, 5.25% sodium hypochlorite with Passive ultrasonic irrigation; Group III, 5.25% sodium hypochlorite with EndoActivator; Group IV, 2% chlorhexidine with Passive ultrasonic irrigation; and Group V, 2% chlorhexidine with EndoActivator. Microbiological samples were collected before and after disinfection using sterile paper points. Quantification of Enterococcus faecalis was performed using conventional culture techniques and qPCR. Data were analyzed using one-way ANOVA, post hoc Tukey test, and paired t-tests (P < 0.05). RESULTS: Post-treatment bacterial counts were significantly lower in all experimental groups than in the saline control (P < 0.001). Group II (NaOCl with Passive ultrasonic irrigation) showed the greatest reduction, with mean post-treatment counts of 1.73 × 10⁵ CFU/mL by culture and a mean log CFU of 3.56 by qPCR, compared with 408 × 10⁵ CFU/mL and 26.54 log CFU, respectively, in the saline control. Both culture and qPCR demonstrated significant reductions in E. faecalis following all active irrigation protocols, with Group II consistently showing the greatest reduction across both detection methods. CONCLUSION: 5.25% NaOCl activated by Passive ultrasonic irrigation achieved the greatest reduction in E. faecalis across both culture and qPCR assessments. CLINICAL SIGNIFICANCE: Passive ultrasonic activation of sodium hypochlorite may enhance root canal disinfection by significantly reducing Enterococcus faecalis, a microorganism commonly associated with persistent endodontic infections. The use of qPCR provides a sensitive method for evaluating the antimicrobial efficacy of endodontic irrigation protocols.