Factors influencing the accuracy of electronic apex locators: A scoping review

The aim of this scoping review (ScR) according to the population, concept, and context question outline was: What factors can affect the accuracy of electronic apex locators (EALs) (concept) when determining the root canal terminus of human permanent teeth (population) in experimental studies (context)?

A ScR was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews checklist using the following databases: PubMed/Medline, Scopus, Web of Science, and ProQuest. Studies that investigated the influence of a factor on the accuracy of the EALs were screened and included according to the inclusion criteria.

A total of 1761 records were retrieved, leading to 805 studies after duplicates were removed. Applying inclusion and exclusion criteria resulted in the inclusion of 166 studies. The 20 potential influencing factors include generation/electrical working mechanism, method for application of EALs, root canal curvature, root canal length, tooth type, maxillary sinus proximity, lateral foramen, major apical foramen diameter/file size, file alloy, apical patency, preflaring, apical periodontitis/resorption, internal root resorption, perforation, irrigants, solvents, and medicaments, pulp contents, pulp vitality, orthodontic brackets, endodontic retreatment, and electromagnetic interferences were detected.

Although the accuracy of EALs is acceptable in most cases, the use of radiography along with EALs remains advisable to confirm the measurement in clinical scenarios.