The Efficacy of Different Retreatment Protocols in the Removal of Root Canal Filling Materials from Oval Root Canal (An In-vitro Study)

Background: When a treatment failure is discovered following a clinical or radiographic evaluation, an endodontic retreatment process is carried out. The most significant etiological causes for failures are the existence of residual germs or re-infection in endodontically treated teeth. Aim: To assess the efficacy of rotary and reciprocation kinematic movements of two different nickel titanium systems in the retreatment of oval canals by evaluation of the amount of remaining gutta-percha with or without solvent as well as crack formation using Edge XR and Reciproc Blue files . Materials and Methods : Thirty-five non-carious extracted human lower second premolars with single straight oval canals will be selected. The occlusal table of the samples will be flattened to achieve a standardized tooth length. They will be randomly divided according to the retreatment system used. Group 1: Edge File XR with solvent, Group2: Edge XR file without solvent, Group 3: Reciproc Blue R25 with solvent, Group 4: Reciproc Blue R25 without solvent. The remaining amount of root canal filling material and evaluation of crack formation will be measured by stereomicroscope. Results: More filling material was observed in the apical third, and there were no notable differences in the percentage of remaining filling materials and working time among the four groups. Conclusion: Achieving the thorough removal of root canal filling material from oval root canals has proven to be challenging with any retreatment approach. Additionally, neither of the kinematics resulted in the occurrence of cracks during the retreatment procedure in oval root canals.