Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 22 0 2026 01 07 4629 4629 Hadi Mokhtari Department of Endodontics, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran Amin Salem Milani Department of Endodontics, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran Fatemeh Yeghaneh Sefidan Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Marziyeh Ejlali Department of Endodontics, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran Atefeh Abedi Department of Endodontics, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran 2022 10 15 2025 08 16 Objectives: Lack of a proper apical seal is one of the most common reasons for root canal treatment failure. Several sealers have been developed in an attempt to enhance the quality of apical seal. Nevertheless, it is essential to evaluate their effectiveness in preventing bacterial penetration. The present study employed a bacterial leakage model to assess and compare the apical sealing ability of three root canal sealers namely AH26, Endoseal MTA, and Sure-Seal Root. Materials and Methods: This in vitro study evaluated 148 extracted single-rooted permanent teeth with almost identical root lengths. The teeth were prepared using the modified crown-down technique, and underwent cleaning and shaping using ProTaper rotary files. Five teeth were selected as positive controls, and five as negative controls. The remaining teeth were randomly assigned to three groups (n=46), and obturated using the abovementioned root canal sealers according to the manufacturers’ instructions. A bacterial leakage model was used to evaluate microleakage. The samples were evaluated daily regarding turbidity resulting from microbial microleakage. The data were analyzed with the Chi-square test and the log-rank test using SPSS 24 (alpha=0.05). Results: The highest bacterial microleakage was recorded in the Sure-Seal Root group (7.21%), while the lowest microleakage was noted in the AH26 group (2.16%). However, there was no significant difference in bacterial microleakage among the three sealer groups (P=0.718). Conclusion: According to the results of this in vitro study, the three sealers evaluated in the present study exhibited a similar performance regarding apical microleakage. https://fid.tums.ac.ir/index.php/fid/article/view/4629 https://fid.tums.ac.ir/index.php/fid/article/download/4629/2196