Evaluation of the accuracy of the NiTi K-files and gutta-percha cones in gauging the apical foramen using the scanning electron microscope: An in vitro study

Objectives: The aim of this study was to compare the accuracy of apical gauging using NiTi K-files and gutta-percha cones and determine the level of agreement between the two methods using a Scanning Electron Microscope (SEM). Methods: 75 circular and straight canals of mandibular first premolars were used. Canals were shaped using the R-Motion system (RM; FKG Dentaire, La Chaux-de-Fonds, Switzerland) and gauged using NiTi K-files and gutta-percha cones matching the shaping instrument. Diameters measured on SEM images were used as the reference standard. Results: There was a statistically significant difference in the prediction of apical diameter by gauging with both NiTi K-files (P < 0.001) and gutta-percha cones (P < 0.001) compared with the measurement of the diameter with the SEM. However, there were no significant differences between both gauging methods. Conclusions: NiTi K-files and gutta-percha cones have similar accuracy but are not accurate in gauging the apical foramen.