Effectiveness of Three Different Retreatment Techniques In Single Canals Filled With Warm Vertical Compaction Technique: An In Vitro Study

AbstractBackground: Complete removal of gutta-percha during endodontic retreatment remains a clinical challenge, particularly in canals obturated using warm vertical compaction.Aim: To compare the effectiveness of H-files, Coltene Hyflex Remover, and ultrasonic endodontic tips in the removal of gutta-percha from root canals.Materials and Methods: Fifty-four extracted single-rooted mandibular premolars were prepared and obturated using the warm vertical compaction technique. The samples were randomly divided into three groups (n = 18): Group I (H-files), Group II (Hyflex Remover), and Group III (Ultrasonic tips). Retreatment was performed using respective techniques. Residual filling material was evaluated in coronal, middle, and apical thirds using a stereomicroscope at 20× magnification and quantified using ImageJ software. Data were analysed using one-way ANOVA and Student's t-test (p < 0.05).Results: Significant differences were observed among all groups in each canal third (p < 0.05). Group II demonstrated the lowest residual filling material in coronal (17.05 ± 2.37), middle (22.55 ± 1.85), and apical thirds (29.64 ± 1.38), followed by Group III and Group I. No significant difference was observed between Groups II and III in the coronal third, while Group II showed superior performance in the middle and apical thirds. The apical third exhibited the highest residual material across all groups.Conclusion: None of the techniques achieved complete removal of obturating material. The Hyflex Remover system demonstrated superior efficacy, followed by ultrasonic tips and H-files, with the apical third remaining the most challenging region for retreatment.