Use of electronic apex locators may improve determination of working length

PubMed, LILACS, Science Direct, Cochrane Collaboration, NHS Evidence databases and in Evidence Based Dentistry and Journal of Evidence-Based Dental Practice.

Randomised controlled trials (RCTs), clinical trials (CTs), diagnostic comparative studies and evaluation studies undertaken in adults where working length determination by both electronic and radiographic methods were used were considered.

Two reviewers independently assessed study quality.

Twenty-one studies were included, five RCTs and 16 in vivo diagnostic test studies. There was considerable heterogeneity between the EALs used and the study designs and a narrative summary of the findings were presented. Working length measurement was compared using three different methods: distance to the radiographic apex in teeth undergoing root canal treatment, (11 studies); concordance between the comparative measurements with EAL and radiography, (two studies); distance to specific anatomic apical reference points evaluated after tooth extraction (four studies)ded. The body of evidence was once again assessed as of low quality.

Within the limitations of this review, it is suggested that working length determination by using EAL may perform better than radiography alone.