Effectiveness of the Severel Irrigation Techniques for Removal of Calcium Hydroxide-based Intracanal Medication from an Artificial Standardized Groove in the Apical Root Canal

Background/aim: This study was aimed to evaluate the efficacy of removal of calcium hydroxide [Ca(OH)2] with the apical negative pressure irrigation system (EndoVac), passive ultrasonic irrigation (PUI), and needle irrigation using sodium hypochlorite (NaOCl). Materials and methods: The root canals of 30 freshly extracted human mandibular premolars were used in this study. Each root canal was prepared with nickel titanium rotary instruments. Each root was split longitudinally through the canal. In one-half, a standardized groove was cut in the canal wall 2–6 mm from the apex, and filled with Ca(OH)2 paste. The roots were reassembled with plastic bracelets. Three techniques were used for Ca(OH)2 removal: Group 1, irrigation using the EndoVac irrigation system; Group 2, PUI; Group 3, needle irrigation; all used a total of 10 mL of 5% NaOCl as the irrigant. The amount of residual Ca(OH)2 in the groove was scored in accordance with previously reported criteria. The data were analyzed with the Kruskal–Wallis and Mann–Whitney U tests. The level of significance was set at p 0.05. Results: No technique removed all Ca(OH)2. There were no significant differences between Groups 1 and 2, and Groups 1 and 3 (p 0.05). There was significant difference between Groups 2 and 3 (p 0.05). Conclusions: PUI was more effective in removing Ca(OH)2 paste from artificial root canal grooves, but the efficacy of PUI did not differ significantly from that of the EndoVac irrigation system.