Surface alterations of Ni-Ti files after retreatment of root canals filled with different sealers:AFM and SEM study

The purpose of this in vitro study is to examine the processing of the surfaces of the files after removing the gutta percha in the root canals with different file systems. In our study, 18 lower molar teeth were used from patients who applied to Zonguldak Bülent Ecevit University Faculty of Dentistry, whose extraction was deemed appropriate for any of the reasons of orthodontic, trauma and periodontal problems. The access cavities for the lower molar teeth were opened, the mesiobuccal canals were shaped and filled with the lateral condensation technique in addition to a single cone. During filling, resin-based canal filling paste was used on half of the teeth (n:9) and bioceramic-based canal filling paste was used on the other half (n:9). All of the canals filled with two different filling pastes were removed using ProTaper Universal Retreatment , Reciproc Blue file (R40) and TF Adaptive rotary file (SM2). Surface changes of the files after removal of the root canal filling material in the canals were examined under Atomic Force Microscope (AFM).