Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 23 0 2026 09 29 5640 5640 Mohammad Ali Ketabi Department of Endodontics, Dental Faculty, AJA University of Medical Sciences, Tehran, Iran Nafiseh Golshahi Department of Endodontics, Dental Faculty, Kashan University of Medical Sciences, Kashan, Iran Babak Farzane Department of Endodontics, Dental Faculty, AJA University of Medical Sciences, Tehran, Iran Ali Hassanzade Salmasi Department of Endodontics, Dental Faculty, AJA University of Medical Sciences, Tehran, Iran Mohammad Mahdi Kiafar Department of Endodontics, Dental Faculty, AJA University of Medical Sciences, Tehran, Iran Mohammad Naseri Department of Endodontics, Dental Faculty, AJA University of Medical Sciences, Tehran, Iran 2025 06 09 2026 04 26 Objectives: Calcium hydroxide (CH) remnants in root canals can compromise root canal sealing, highlighting the need for effective removal techniques. This study assessed the efficacy of Gentlefile Finisher Brush (GB), in combination with ethylenediaminetetraacetic acid (EDTA), for CH removal by stereomicroscopic evaluation. Materials and Methods: This in vitro study evaluated CH removal from 66 extracted single-rooted mandibular incisors. After canal preparation with ProTaper up to F2 and CH application, the specimens were incubated for 10 days and randomly divided into six groups on the basis of the irrigation method and instrument used: master apical file (MAF) or GB with saline or 17% EDTA (n=15 each) and positive and negative control groups (n=3 each). The CH was removed accordingly, and the teeth were longitudinally sectioned. The residual CH was quantified under a stereomicroscope at ×10 magnification using Digimizer software to compare the efficacy of different protocols. Data were analyzed using ANOVA and Tukey’s test (alpha=0.05). Results: The combination of GB with 17% EDTA resulted in the lowest residual CH (8.30%±6.29%) significantly outperforming all other protocols (P<0.05). MAF with saline resulted in the highest residue (52.27%±19.24%). The Tukey’s post-hoc test confirmed that both the GB methods were significantly more effective than their MAF counterparts (P<0.05), while no significant difference was observed between the two MAF-based methods (P>0.05). Conclusion: GB with 17% EDTA demonstrated superior efficacy in removing CH from root canals. These results highlight the importance of combining chelating irrigation with dynamic mechanical agitation to optimize intracanal cleanliness. https://fid.tums.ac.ir/index.php/fid/article/view/5640 https://fid.tums.ac.ir/index.php/fid/article/download/5640/2242