Integrated electronic apex locators for determining working length: a systematic review of in-vitro studies

To evaluate the reliability of integrated electronic apex locators (EALs) compared to other methods (traditional apical locators, radiographic determination) in determining the working length (WL) and to summarize the current evidence on their clinical performance. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020. In vitro studies published from January 2010 to November 2024 were included. PubMed, Scopus, and Web of Science databases were searched, and relevant peer-reviewed journals were manually screened. Two reviewers performed the study selection and data extraction independently. Quality assessment was performed using Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2). A total of 883 articles were identified, with 10 studies included. The studies were conducted across six countries. Sample sizes ranged from 15 to 120 human permanent teeth, and various endodontic motors integrated with EALs were identified. Most studies reported that integrated EALs provided comparable or superior accuracy to traditional methods. Devices like the Gold Reciproc Motor (VDW) and TriAuto ZX (Morita) demonstrated high reliability in WL determination. The risk of bias was mostly unclear, particularly for the index test and flow/timing domains. Details on sample selection were lacking, but overall, no major concerns were identified in the applicability domains. Integrated EALs generally provide accurate WL determination, enhancing endodontic treatment reliability. While variability in performance and the unclear risk of bias in many studies require cautious interpretation, integrated EALs are a reliable alternative to traditional methods. Further research is needed to optimize their use in diverse clinical scenarios.