Assessment of Root Dentin Defect during Retreatment Procedure using Various NiTi Hand and Rotary Retreatment Files: An In vitro Study

AIM: The aim of the current study was to evaluate the radicular dentin defect during retreatment employed diverse NiTi hand and rotary retreatment file systems. MATERIALS AND METHODS: Eighty mandibular premolars with a single root and root canal that were recently extracted were gathered and stored. The premolars were subject to decoronation at cementoenamel junction (CEJ) beneath irrigation with water to attain a uniform radicular length of 16 mm. Gutta-percha cones were covered with sealer and introduced into the root canal up to the working length. Eighty teeth were allocated at random into four groups with each group consisting of 20 samples. Group I: Control, Group II: EdgeFile XR retreatment rotary files, Group III: ProTaper Universal retreatment files, and Group IV: MTwo retreatment files. Under constant water cooling, the roots were cut flat with a diamond disc at apical third (3 mm), middle third (6 mm), and cervical third (9 mm) points. Stereomicroscope was employed to visualize the sections below × 20 magnification. RESULTS: A statistically significant difference was noted among the groups with respect to the formation of radicular dentinal defects at 3 mm (P < 0.01) and 6 mm (P < 0.001), while the sections at 9 mm did not exhibit any statistically significant difference (P > 0.598). CONCLUSION: Despite the limitations in this study, it was concluded that all the evaluated file systems efficiently eliminated root canal filling during the retreatment. In addition, it was noted that the EdgeFile XR group exhibited fewer root dentin defects in comparison with the MTwo and ProTaper Universal group of files.