The method followed was a modification of the technique described previously by Berber et al.[11 (link)] A total of 180 extracted human mature maxillary central incisor teeth with a single root and without root resorption was selected. The crowns were removed with a water-cooled diamond saw (Buehler Ltd., Lake Bluff, IL, USA) to leave uniform 15 mm apical sections of root.
The root canal instrumentation was done using an endodontic X-Smart micro-motor (Dentsply-Maillerfer, Ballaigues, Switzerland) at a speed of 350 rpm with ProTaper NiTi rotary files (Dentsply, Tulsa Endodontics, OK, USA) to size #F3 with the crown-down manner. The 180 specimens were randomly assigned to 15 groups (n = 12 for each), antimicrobial evaluation was performed in the first seven groups. In the other eight groups, effect of the solutions on the smear layer was studied.
The smear layer was removed in the first seven groups with 3 ml 17% ethylenediaminetetraacetic acid (EDTA) (Merck KGaA, Darmstadt, Germany) for 1-min, followed by 3 ml 5.25% NaOCl (Wizard, Ankara, Turkey) for 1-min, and then 5 ml distillate water for 1-min as outlined by Teixeira et al.[12 (link)] Samples were after that autoclaved at 121°C at 1 atm for 20 min, and then placed into glass tubes containing 5 ml of brain heart infusion (BHI) broth medium (BHI, Oxoid, Basingstoke, UK).
The root canal instrumentation was done using an endodontic X-Smart micro-motor (Dentsply-Maillerfer, Ballaigues, Switzerland) at a speed of 350 rpm with ProTaper NiTi rotary files (Dentsply, Tulsa Endodontics, OK, USA) to size #F3 with the crown-down manner. The 180 specimens were randomly assigned to 15 groups (n = 12 for each), antimicrobial evaluation was performed in the first seven groups. In the other eight groups, effect of the solutions on the smear layer was studied.
The smear layer was removed in the first seven groups with 3 ml 17% ethylenediaminetetraacetic acid (EDTA) (Merck KGaA, Darmstadt, Germany) for 1-min, followed by 3 ml 5.25% NaOCl (Wizard, Ankara, Turkey) for 1-min, and then 5 ml distillate water for 1-min as outlined by Teixeira et al.[12 (link)] Samples were after that autoclaved at 121°C at 1 atm for 20 min, and then placed into glass tubes containing 5 ml of brain heart infusion (BHI) broth medium (BHI, Oxoid, Basingstoke, UK).