Accuracy of Different Apex Locators in Teeth with Simulated Apical Root Resorption: an In Vitro Study.

Background: Accurate working length (WL) determination is necessary in achieving optimal healing by non-surgical root canal therapy in teeth with inflammatory apical root resorption. Electronic apex locators (EALs) are one of the mainstays in determination of WL of teeth.
Aim: This study evaluated the accuracy of three EALs [RootZX (third generation), iPex (fourth generation) and Raypex 6 (modification of a fifth generation)] in determining the WL of teeth with simulated apical root resorption in permanent teeth.
Materials and Methods: Forty freshly extracted maxillary anterior teeth were collected and a 45° oblique cut was made at the root apex with a disc to simulate apical root resorption. Actual working length (AWL) was determined by direct visual method and was used as a control. Electronic working length (EWL) values were measured by three different apex locators that are RootZX (Group I), iPex (Group II) and Raypex 6 (Group III) at apex, 0.5 mm and 1 mm from apex. All values obtained were tabulated and statistical evaluation was carried out.
Results: At apex, EWL obtained using iPex (p=0.05) showed a statistically significant difference from AWL. At 0.5 mm and 1.0 mm tolerance, iPex showed non-acceptability for WL measurement in 67.5% and 17.5% of samples compared to Root ZX (12.5% and 2.5%) and Raypex (7.5% and none) respectively.
Conclusion: Within the limitation of this study, it can be concluded that Raypex 6 and RootZX show statistically significant accuracy in WL measurement compared with iPex in teeth with apical root resorption.