Comparison of two different methods in the removal of oil-based calcium hydroxide from root canal system: A triple-blinded randomised clinical trial

Objective: To compare the effectiveness of rotary master apical file (RMAF) with ultrasonic activation of endodontic file (UAF) in the removal of silicon oil-based calcium hydroxide (SOBCH) from the canal. Methods: Ethical review committee approval and informed consent was obtained. 60 cases with necrotic teeth in which silicon oil-based intracanal medicament (Metapex) was to be placed were randomised in one of the two groups using sealed envelopes containing assignment codes for medicament removal: RMAF and UAF group. After standard protocol of coronal access, cleaning and shaping, silicon oil-based SOBCH was placed using a Lentulo spiral. A periapical radiograph was taken after SOBCH placement to check for adequate adaptation. On 7^th day, after instrumentation and medicament removal according to respective group, a second radiograph was taken to evaluate the effectiveness. Effectiveness was calculated using a graded scale in which 0 and 1 are effective and 2 and 3 are ineffective cleaning. Teeth were statistically analyzed using the Mann Whitney U and Chi-square test. Results: There was no statistically significant difference in the removal effectiveness of group RMAF and Group UAF at coronal (P=0.74) middle (P=0.71) and apical third (P=0.68). According to the graded score both techniques were equally effective in cleaning at all thirds of canal (RMAF=Apical: 1.09±0.70, Middle: 0.61±0.80, Coronal: 0.33±0.48 and UAC=Apical: 1.00±0.77, Middle: 0.52±0.74, Coronal: 0.28±0.46). Effectiveness of SOBCH removal using the two methods was not statistically significant between maxillary and mandibular teeth (P=0.35). Conclusion: Both the removal methods, Ultrasonic activation of file and Rotary master apical file, for SOBCH were equally effective in all the thirds of canal. And none of the techniques were able to completely remove the SOBCH. Effectiveness of SOBCH removal using the two methods was not statistically different between maxillary and mandibular teeth.