Comparison of Five different methods of Working length determination: An ex vivo study

Abstract

Aim: The aim of the study was to determine the accuracy and reliability of working length determination using tactile sensation method, digital radiographic method, and electronic apex locator (EAL) in lower premolars in vivo and to compare the lengths so measured to the working length measured with cone-beam computed tomography (CBCT) and the actual working length (AWL) with magnifying loupe, ex vivo. Materials and Methods: Thirty mandibular premolars scheduled for orthodontic extraction were selected. Under local anesthesia, access cavities were prepared and the working lengths were determined by two operators after blinding, using the tactile sensation method, digital radiographic method (radiovisiography [RVG]), and EAL, and tabulated. The teeth were then extracted and subjected to CBCT to determine the working length (CBCTWL). The AWL of the teeth was measured with a K-file that was inserted into the root canal until the file tip is visible at the apical foramen which was confirmed using a magnifying loupe (×8). The values were then statistically analyzed. Statistical Analysis: The SPSS version 20 software (IBM Corp., Armonk, NY, USA) was used to perform statistical analyses, and the confidence interval was determined at P Results: There is a significant difference between the methods in determining the working length. Based on the correlation values on reliability, CBCT method has a more positive correlation with AWL measured using magnifying loupe, followed by EAL, RVG, and tactile sensation. Conclusion: Hence, we conclude that the use of EAL technique is clinically effective for measuring the working length which correlates more positively with the CBCTWL and AWL. Diagnostic CBCT scan can be used as a reliable method for determining the working length.