Power of Apical

In endodontic practice, electronic apex locators (EALs) and radiographic methods are routinely employed to determine the working length (WL) of root canals. Although EALs provide highly reliable results based on impedance changes at the apical constriction, discrepancies are occasionally observed when compared with radiographic evaluation. Specifically, the apex locator may record a shorter canal length than that suggested radiographically. This apparent underestimation is not an error but rather reflects the biological and anatomical reality of the apical region. The apical constriction—the narrowest portion of the canal—does not always coincide with the radiographic apex. Numerous histological studies have shown that the cementodentinal junction (CDJ), which represents the most favorable endpoint for instrumentation and obturation, lies coronal to the anatomic apex in…