Keywords Enterococcus faecalis, Conventional endodontic retreatment, sonic agitation, laser activation, bacterial eradication, EndoActivator, Irrigation Disciplines Bacteria | Bacterial Infections and Mycoses | Chemicals and Drugs | Dental Hygiene | Dentistry | Education | Endodontics and Endodontology | Medical Sciences | Medical Specialties | Medicine and Health Sciences | Oral Biology and Oral Pathology Abstract Enterococcus faecalis is the most common bacteria isolated in conventional endodontic retreatments. Aim: To compare the impact of three irrigation modalities on the elimination of the isolated microbial strains of Enterococcus faecalis. Materials and Methods: Thirty patients requiring conventional endodontic retreatment for one of their mandibular premolars and tested positive for E. faecalis were chosen. Patients were randomly divided into three groups (n=10) according to the irrigation modality to be used; group I: syringe irrigation (NaOCl 2.625%), group II: NaOCl 2.625%+EndoActivator and group III: NaOCl 2.625%+diode laser. Before obturation, samples S2 were collected and PCR analysis was performed to identify the persistence of E. faecalis post- irrigation. Fisher exact test was used for differences in proportion between the three irrigation modalities. Analysis was achieved at the 0.05 significance level. Results: A significant statistical difference was revealed between group I and each of groups II and III whereas the statistical difference between groups II and III was not significant. Conclusion: Agitation with EndoActivator or activation with diode laser are necessary for a better eradication of E. faecalis in conventional endodontic retreatments. Recommended Citation Khaled, Fadl H.; Abiad, Roula S.; Abd El Galil, Khaled; and Osman, Essam (2021) "ERADICATION OF ENTEROCOCCUS FAECALIS IN CONVENTIONAL ENDODONTIC RETREATMENTS (A RANDOMIZED CLINICAL TRIAL)," BAU Journal - Creative Sustainable Development: Vol. 3: Iss. 1, Article 4. Available at: https://digitalcommons.bau.edu.lb/csdjournal/vol3/iss1/4