Türkyilmaz, A.Erdoğan, D.Akbal Dinçer, G.Erdemir, A.2025-07-152025-07-1520222148-752910.15311/selcukdentj.8875702-s2.0-105007652435https://doi.org/10.15311/selcukdentj.887570https://hdl.handle.net/20.500.14517/8091Background: This study aimed to compare apical transportation and canal straightening of ProTaper Next, HyFlex Electric Discharge Machining, Reciproc and Reciproc Blue nickel-titanium (NiTi) files with different apical enlargements. Methods: Forty-eight mandibular molar human teeth were included in the study. The teeth were divided into four groups according to the NiTi file types (n=12). A digital radiographic method was used to compare apical transportation and canal straightening in the buccolingual and mesiodistal directions using before-and-after images superimposed with Image J software. The Kruskal-Wallis test with Bonferroni correction and the Wilcoxon test were used; the P value was set at 5%. Results: The maximum transportation of the buccolingual and mesiodistal directions were 0.216 mm and 0.196 mm with Reciproc file. The maximum straightening of the buccolingual and mesiodistal directions were degrees of 8.661 and 8.048 respectively with ProTaper Next and Reciproc files. Conclusion: ProTaper Next, HyFlex Electric Discharge Machining and Reciproc Blue filespresented similar results. Using a larger instrument increased the apical transportation and canal straightening. © 2022, Selcuk University. All rights reserved.eninfo:eu-repo/semantics/closedAccessApical TransportationCanal StraighteningHyFlex EDMProTaper NextReciproc BlueArticleN/AN/A92402408