Efficacy of Four Techniques for Removing Calcium Hydroxide from the Apical Third of Root Canals: An in Vitro Study

Abstract Background: Complete removal of calcium hydroxide [Ca(OH)₂] before obturation is critical for optimal sealer adaptation and long-term endodontic success. However, limited irrigant penetration and canal intricacy make cleaning the apical third difficult. Objective: To assess the effectiveness of four commonly used techniques Passive Ultrasonic Agitation (PUA), Master Apical File (MAF), XP-endo Finisher, and H-file instrumentation in removing Ca(OH)₂ from the apical third of root canals. Methods: This in vitro comparative cross-sectional study was conducted from October 2022 to September 2023 at BSMMU, Dhaka, in collaboration with BUET. A total 64 freshly extracted single-rooted mandibular premolars were purposively selected and randomly assigned to four groups (n=16). Canals were prepared, filled with Ca(OH)₂ paste, and stored for one week. Ca(OH)₂ was then removed using PUA (Group A), MAF (Group B), XP-endo Finisher (Group C), or H-file instrumentation (Group D). Residual Ca(OH)₂ in the apical third was evaluated via SEM (×300–×2000) and scored on a 5-point scale by two blinded examiners. Results: XP-endo Finisher (Group C) yielded the lowest mean residue score (1.94±0.68), followed by Passive Ultrasonic Agitation (Group A) (2.88±1.09), indicating superior cleaning efficacy. Master Apical File (Group B) and H-file instrumentation (Group D) showed significantly higher residue scores (4.81±0.40 and 5.0±0.0), demonstrating limited effectiveness. Differences among groups were statistically significant (p