Comparative evaluation of accuracy of 2 electronic Apex locators with conventional radiography: an ex vivo study

The aim of this ex vivo study was to evaluate the accuracy of the Raypex 5 (VDW, Munich, Germany) and Apex NRG XFR (Medic NRG Ltd, Tel Aviv, Israel) electronic apex locators (EALs) in determining the working length when compared with radiographs.

Twenty-five human single-rooted teeth were selected, and the access cavity was prepared. The working length (WL) was determined radiographically and electronically by using 2 EALs. The files were fixed at the WL, and the teeth were extracted. The apical 4 mm of each canal was trimmed to expose the file tip, and the samples were observed under a stereomicroscope. The distance from the file tip to the point 0.5 mm coronal to the anatomic apex was measured. The data were analyzed by using 1-way analysis of variance and the Tukey Honestly Significant Difference test.

There was no significant difference between the Raypex 5 and the Apex NRG XFR devices with respect to their accuracy in determining the final WL. When compared with radiography, both the EALs had no significant difference. When comparing EALs and radiographic measurements with control measurements, accuracy results were found to be 20%, 36%, and 52% for the Raypex 5, Apex NRG XFR, and radiography, respectively. Overestimations of WL determination by the Raypex 5, Apex NRG XFR, and radiography were 4%, 0%, and 40%, respectively. Underestimations of WL determination by the Raypex 5, Apex NRG XFR, and radiography were 76%, 64%, and 8%, respectively.

Both the EALs had the same accuracy in determining the WL when compared with radiography.