Comparative Accuracy of Digital Apex Locators and Conventional Radiography in Endodontic Working Length Measurement for Permanent Teeth

Abstract

Introduction: This study has discussed about the accurate working length (WL) determination is crucial for effective root canal treatment, preventing over- or under-instrumentation. Accurate working length determination is crucial for successful endodontic treatment. While conventional radiography has limitations, Digital Apex Locators (DALs) provide an effective alternative, offering accurate WL measurements by assessing electrical resistance in the canal. Studies suggest DALs have comparable accuracy to conventional methods and may reduce postoperative discomfort and radiation exposure. Combining DALs with radiography can enhance accuracy, especially in complex cases.

Method: A systematic review was conducted from January to July 2025 using PRISMA guidelines and PICOS framework. Searches were made across databases like PubMed, Cochrane, and EBSCOhost. Included studies were RCTs, in vivo, in vitro, and clinical trials involving permanent teeth, comparing DALs such as Root ZX, Raypex with conventional radiographic methods. Key outcomes measured were measurement accuracy, postoperative pain, obturation capability, and radiation exposure. Bias risk was assessed using the ROBIS tool.

Results: Eleven studies met the inclusion criteria. DALs presented comparable or superior accuracy to radiography, with accuracy ranging from 43.9% to 92.1%. DALs significantly reduced radiation exposure and yielded fewer overextended cases. Postoperative pain and analgesic usage presented no significant alterations between methods. Combined usage of DALs and radiographs was recommended for improved accuracy, particularly in anatomically complex cases. Risk of bias was moderate to high in most studies.

Conclusion: The study has concluded that the evidence indicates that Digital Apex Locators (DALs) generally provide accuracy comparable to or higher than conventional radiography in determining working length, with rates often exceeding 85–90% in many studies.