Efficacy of Sonic and Ultrasonic Irrigation for the Removal of Calcium Hydroxide Paste in the Root Canal : A Microtomographic Study

Abstract

Purpose: The purpose of this study was to evaluate the efficacy of sonic and ultrasonic irrigation on calcium hydroxide (Ca(OH)₂) paste removal and to measure the volume of remaining Ca(OH)₂ paste in the root canal with micro-computed tomography scanning (micro-CT). Methods: Twenty-one root canal models (D-mec) were used. These models had two orifices and one apical foramen with two isthmuses positioned 5 and 9 mm from the apex, respectively. All root canal models were filled with Ca(OH)₂ paste (Calcipex II, Nihon Shika Yakuhin). After 7 days, the root canal models were randomly divided into one control group (n=7) and two experimental groups (n=7 each). Groups A, B and C were irrigated using a conventional syringe (3.0 ml syringe, Terumo) with a needle (Blunt®, Nipro), a sonic Sally (Yoshida), and an ultrasonic Grand Piezo (Yoshida), respectively. After irrigation (Group A: 30 sec, Groups B and C: 15 sec , the root canal models were scanned using micro-CT (InspeXio SMX100CT®, Shimadzu), and the volume of remaining Ca(OH)₂ paste was measured. One-way ANOVA and Tukey-Kramer were used for statistical analysis (p<0.05). Results: No techniques removed the Ca(OH)₂ paste completely from the root canal. Although more remnants of Ca(OH)₂ paste remained in Group A (control) than in Groups B and C (p<0.05), there was no significant difference in the volume of Ca(OH)₂ paste remnants between Groups B and C. Conclusion: The results indicated that sonic and ultrasonic irrigation were significantly more effective for removing Ca(OH)₂ paste from the root canal than manual irrigation. No significant difference was found between Group B (sonic irrigation) and Group C (ultrasonic irrigation).