Clinical Efficacy of Electronic Apex Locators: Systematic Review

By Martins J, Marques D, Mata A, Caramês J.


  • Purpose: to determine if electronic apex locator more accurate and reduces the radiation compared to RG method.
  • Concordance of the Measurements by EAL When Compared with the Measurements of Radiography: effective values were obtained in 97% of the cases with the apex locator between the 0.5-1-mm mark (Akisue et al,2007). 73.6% accept- able readings with the apex locator 1 mm mark (Renner et al,2012).
  • Distance to the Apical Constriction, Cementodentinal Junction, and Apical Foramen:
  • Apex locator method significantly better than RG, and there is no significant difference between various apex locators. Table 1.
  • In one study when apex locator was used alone 84% of the lengths obtained were at a distance of ±0.5 mm to the apical constriction; when the working lengths were rectified after radiographic analysis, there was improvement of efficiency(96%).
  • Distance from CDJ was 0.09 mm when apex locator was used and 0.26 when RG was used
  • Number of Radiographs Taken:  is less when using EAL.