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

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.

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.

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.

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.

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.