Accuracy of an Electronic Apex Locator for Working Length Determination in Primary Anterior Teeth

Correct determination of working length is an important step for success of endodontic therapy. Conventional radiography has limitations in providing the accurate location of apical foramen. For this reason, electronic apex locators (EALs) were developed to shorten the treatment time and decrease the radiation dose. The aim of this study was to evaluate the accuracy of Root ZX EAL for working length determination in primary anterior teeth.

In this in-vitro study, 50 extracted primary anterior teeth with root resorption were selected with no obstructed canals or history of previous root canal therapy. Working lengths were measured by direct observation of actual length (AL), radiography and Root ZX EAL. A variation of ±0.5 mm from the AL was considered acceptable. The results were analyzed statistically using paired t-test and interclass correlation coefficient (ICC) at 0.05 level of significance.

Considering an acceptable 0.5 mm margin from AL (direct measurement), the accuracy of Root ZX EAL and radiography was found to be 86% and 76%, respectively. Absolute value of error from AL was significantly lower for ZX compared to radiography (P<0.001). Interclass correlation comparing both radiography and Root ZX with AL showed strong correlations.

Root ZX EAL can be used as a reliable tool for obtaining root canal length in primary anterior teeth with resorption.