A Comparative Evaluation of Four Different Techniques for Determining the Accuracy of Root Canal Working Length: An In Vitro Study

Complete disinfection of root canal is one of the main objectives of root canal treatment. However, complete disinfection is only possible after correct determination of root canal working length. Thus, determining a correct working length is essential for endodontic success. Thus, the present study was conducted with the aim to comparatively evaluate the accuracy of four different techniques in determining root canal working length.

30 freshly extracted human single-rooted teeth were taken. After sectioning the teeth at the cemento-enamel junction, K-Flexofile with size 10 was used to check the patency of canal and major foramen. Each sample was then subjected to all the four techniques. The four techniques used were conventional radiography, radivisiography, electronic apex locator (raypex 6) and cone beam-computed tomography. After calculating each root canal length of samples, their actual length was measured by using K- Flexofile until its tip became visible through the major foramen. The file was taken out when a magnifying glass showed its tip at the coronal border of major foramen. The adjustment of rubber stop was done according to the occlusal reference, and then the distance between the stop to the file tip was measured. Finally a comparison was done for each sample between the root canal length recorded with the four techniques and the actual length.

Mean of absolute differences with respect to actual length was lowest in case of electronic apex locator whereas, it was highest in case of cone beam-computed tomography. Conventional radiography and Radiovisiography had negative mean difference values that showed overestimated canal length. A significant difference was observed between cone beam-computed tomography and the other three techniques respectively (P < 0.05).

Raypex 6 apex locator was more accurate than the other three techniques in determining root canal working length.