After every change of endodontic file or Gates-Glidden drill, each canal was irrigated with 3 mL of irrigation solution. Two different endodontic irrigants were used. The teeth in groups 1 and 2 were irrigated with 5.25% NaOCl (Dentpro, Ammdent, Chandigarh, India) followed by 17% EDTA (Prevest DenPro, Jammu, India) and the teeth in groups 3 and 4 were irrigated with QMix (Dentsply, Tulsa Dental Specialties, Tulsa, OK). Both control groups (groups 5 and 6) were irrigated with sterile saline solution. Finally, the root canals were flushed with 2 mL of saline solution.