In Vitro Accuracy of the E-PEX Electronic Apex Locator Compared to the Root ZX II in the Presence of Various Irrigation Solutions

Abstract

Introduction: Determining the end point of instrumentation and obturation is one the most important aspects of a well-done non-surgical root canal treatment (NSRCT). This reference point determines the working length, and is commonly calculated with the aid of an electronic apex locator (EAL), which accurately identifies the apical foramen which in turn determines the working length. Throughout endodontic procedures, clinicians utilize a range of irrigants to chemically debride and disinfect the root canal system (RCS), often operating an EAL concurrently in the presence of these solutions. These solutions may affect the accuracy of EALs. Recently a new EAL that uses multiple frequencies has been introduced that may offer benefits over existing EAL’s. Objectives: This study aims to evaluate the accuracy of a novel EAL, the E-PEX, in comparison to the well-established Root ZX II, in determining the position of the apical foramen under the influence of various endodontic irrigants. Materials and Methods: Fifty-six extracted single-rooted teeth had the distance from a coronal reference point to the apical foramen measured. The visual length (VL) was determined using a dental operating microscope (DOM) by placing a #10 K-file in the canal and visualizing where it exits the tooth under magnification. Teeth were then mounted in alginate as a conducting medium, placing various irrigation solutions in the canal during measurements: saline (0.9% sodium chloride), 3% NaOCl, 17% EDTA, and 2% chlorhexidine gluconate. The measurements for the apical foramen were made using the Root ZX II and E-PEX. The length measurements of both EALs were compared for accuracy against the VL measurement. Outcome: The E-PEX and the Root ZX II were both be able to accurately determine the canal length. The different irrigation solutions used did not affect the accuracy of both EALs when allowing for a 0.5mm margin of error. This study provides further support for the use of the E-PEX electronic apex locator in the clinical setting.