Assessment of working length determination using apex locator vs radiograph

Accurate determination of working length is crucial for successful endodontic therapy, as it ensures complete cleaning, shaping, and obturation of the root canal system while preventing over- or under-instrumentation. Traditional radiographs are widely used but have limitations, whereas electronic apex locators (EALs) offer an alternative method for precise measurement.

To assess and compare the accuracy of working length determination using an electronic apex locator versus conventional radiographic methods in extracted human teeth.

Forty extracted single-rooted human teeth were included in this in-vitro study. Working length was determined using an electronic apex locator and conventional periapical radiographs. Measurements were compared with the actual working length determined visually under magnification. Data were analyzed using paired t-tests to evaluate differences in accuracy.

The apex locator demonstrated higher accuracy and closer agreement with the actual working length compared to radiographs. Mean deviation from the actual length was 0.12 mm for the apex locator and 0.42 mm for radiographs. Ninety percent of apex locator measurements were within ±0.5 mm of the actual length, whereas only 65% of radiographic measurements fell within this range. Statistical analysis confirmed that the apex locator was significantly more accurate than radiographs.

Electronic apex locators provide more precise and reliable working length determination than conventional radiographs, reducing the risk of over-instrumentation and extrusion of filling materials. Combining EALs with radiographs may optimize accuracy and improve clinical outcomes in endodontic treatment. However, results can vary depending on canal anatomy, operator experience, and device type, and further studies with larger sample sizes are required to validate these findings.