Aim: This study aims to evaluate and compare the apical sealing ability of different obturation techniques using bioceramic and siliconeâbased root canal sealers in an in vitro setting. Materials and Methodology: Twentyâfive extracted mandibular premolars were standardized to 15 mm root length and instrumented using ProTaper Universal NiâTi rotary files. The samples were randomly divided into five groups (n = 5) based on the obturation technique and sealer used. Group 1 and Group 2 were obturated using thermoplasticized guttaâpercha with mineral trioxide aggregate (MTA) Fillapex and Ceraseal, respectively. Group 3 and Group 4 utilized bioceramic guttaâpercha with MTA Fillapex and Ceraseal, respectively. Grop 5 employed singleâcone obturation (SCO) with GuttaFlow 2. Apical microleakage was assessed using methylene blue dye penetration, and measurements were analyzed under a stereomicroscope at Ã20 magnification using ImageJ software. Statistical analysis was performed using oneâway ANOVA (P < 0.05). Results: All groups exhibited varying degrees of apical leakage. Group 5 (GuttaFlow 2 with SCO) demonstrated the lowest mean leakage (0.87 ± 0.26 mm), whereas Group 1 (thermoplasticized guttaâpercha with MTA Fillapex) had the highest leakage (2.66 ± 0.61 mm) (P < 0.05). Conclusion: Although none of the sealers completely prevented apical leakage, GuttaFlow 2 with SCO exhibited the most effective sealing ability. The findings suggest that siliconeâbased sealers may provide enhanced apical sealing in root canal therapy. Further studies with larger sample sizes and clinical validation are warranted. © 2025 Elsevier B.V., All rights reserved.