ABSTRACT Aim: The aim of this study was to evaluate the efficacy of self-adjusting files (SAFs) and the E18 isthmus ultrasonic tip as supplementary instruments following the use of neoendo retreatment files for removing gutta-percha (GP) and bioceramic (BC) sealer during the retreatment of oval canals using cone-beam computed tomography (CBCT). Methods: Forty-five extracted mandibular premolars with oval canals were prepared to a length of 16 mm after decoronation. Canals were prepared with the Neoendo flex rotary system up to size #40, followed by obturation with GP and BC sealer (Ceraseal) by cold lateral compaction. CBCT scans of all the samples were taken to analyze the volume of the filling material. Retreatment was then performed in all the samples with the neoendo retreatment file system. The samples were divided into three groups (n = 15) based on the supplementary instruments to be used in removing the remaining filling material as follows: GROUP I: no supplementary instrument, GROUP II: SAF, and GROUP III: E18 Isthmus Ultrasonic tip. CBCT scans were taken after the use of supplementary instruments, and the volume of residual filling material was measured. Results: GROUP II (SAF) exhibited the lowest mean percentage of remaining filling material, followed by GROUP III (E18 ultrasonic tip) and GROUP I (no supplementary instrument). The differences in the mean percentage of residual filling material among the three groups were statistically significant (P < 0.001). Conclusion: None of the supplementary instruments eliminated GP and BC sealer completely from the canals. However, the use of supplementary instruments enhanced the removal of filling material following the primary retreatment. SAF proved to be more effective than the E18 isthmus ultrasonic tip in removing GP and BC sealer during the retreatment of oval canals.
Madolil et al. (Tue,) studied this question.