Comparative Evaluation of Remaining Dentin Thickness and Removal of Root Canal Filling Material Using Two Obturation Techniques and Two Retreatment File Systems– An Invitro Study

Background: Successful endodontic retreatment requires effective removal of root canal filling material while preserving dentin integrity. Both obturation techniques and retreatment systems play a crucial role in determining these outcomes. Aim: To comparatively evaluate remaining dentin thickness (RDT) and removal of root canal filling material (RFM) using two obturation techniques and two retreatment file systems. Materials and Methods: Sixty extracted single-rooted mandibular premolar were divided into two groups based on obturation technique(n=30): lateral compaction and Obtura (C-Fill) system. Each group was subdivided based on retreatment file system: Hyflex Remover and Endostar REvision (n=15 each). All canals were obturated using gutta-percha with AH Plus sealer. Retreatment was performed using the respective systems. RDT was analyzed using CS 3D imaging software, and volumetric analysis of residual filling material was performed using 3D Slicer software (version 5.8.1). Data were analyzed using ANOVA and Tukey post hoc tests. Results: The least residual filling material (RFM) was observed in the Lateral Compaction + Hyflex group, while the highest was seen in the Obtura + REvision group. Hyflex demonstrated superior removal efficiency compared to Endostar REvision. Tukey analysis revealed that REvision caused greater dentin removal in coronal and middle thirds, whereas Hyflex resulted in increased dentin removal in the apical third. All intergroup differences were statistically significant (p < 0.05). Conclusion: Both obturation technique and retreatment system significantly influence retreatment outcomes. Hyflex showed superior cleaning efficiency, while dentin preservation varied across root levels between systems.