An in vitro study: Evaluation of intracanal calcium hydroxide removal with different file systems

Background: Calcium hydroxide (Ca(OH) 2 ) is the most commonly used intracanal material; it needs to be removed in entirety before obturation. Several techniques have been used for the same including use of various hand and rotary files. Aim: This study was carried out to compare the efficacy of Hand K files and single and multiple rotary file system in removal of Ca(OH) 2 . Methodology: Distobuccal root of 45 maxillary molars were selected on the basis of specified inclusion and exclusion criteria. They were divided into three groups - Group 1 (H and K file), Group 2 (HERO Shaper), and Group 3 (One Shape). Biomechanical preparation (BMP) was carried out as per the manufacturer's instructions; 2.5% sodium hypochlorite was used as the irrigant and 17% ethylenediaminetetraacetic acid as the penultimate irrigant. Ca(OH) 2 powder was mixed with normal saline to obtain a paste; canals were filled with this paste using a Lentulo spiral and were sealed. After 7 days, Ca(OH) 2 was removed, using the same file system as that used for BMP. Samples were sectioned longitudinally and evaluated under a stereomicroscope. Statistical Analysis: Statistical analysis of the obtained data was carried out using one-way analysis of variance test. Results: HERO Shaper displayed better removal of Ca(OH) 2 than One Shape and Hand K file. Moreover, removal was better in the middle third of canal than apical third. Conclusion: Multiple rotary file system (HERO Shaper) is more effective in removal of Ca(OH) 2 than the single file system (One Shape)