Influence of Irrigant Solutions and Apex Locators in Working Length Determination

The objective of this study is to evaluate the accuracy of three apex locators using four irrigant solutions to determine the working length of root canals. Material and methods: thirty unirradicular teeth were used. Teeth were randomly divided into three groups, in order to establish the working length, using different apex locators: Raypex 6, Endo EZE and RootOR. Four different irrigant solutions were used combined with the apex locators: saline solution (0.9% sodium chloride), 2% chlorhexidine digluconate, 18% EDTA and 5.25% NaCLO. Real working length (RWL) was determined using a #15 K-file in each specimen until the end of the file was visualized in stereoscopic microscopy. Scores (%) were attributed to each difference found between the working length gave by the apex locators and the RWL. Results: there was a significant difference between the RWL and that one found with the apex locators Raypex 6 and RootOR; however, Endo EZE did not show statistical differences. The four different irrigant solutions did not show statistically differences between then. Conclusions: the precision to estimate the working length with Raypex 6 and RootOR was affected by the different irrigant solutions in the root canal; Endo EZE was the most accurate apex locator to estimate the RWL.