In vitro evaluation of the accuracy of the fourth generation electronic apex locator: Apex ID

Background: To achieve success in endodontic treatment, the working length must be precisely defined and maintained during preparation. The introduction of the electronic apex locator makes it possible to determine the working length quickly and accurately. Apex ID is the 4th generation electronic apex locator, which can determine the working length in humid conditions. The objective of the study was to evaluate the accuracy of the Apex ID apex locator. Materials and methods: In vitro study on 50 orthodontic extracted mandibular premolars, measured working length by Apex ID apex locator. The measured value was compared with the actual length of the canal and the working length was determined by periapical X-ray. The accuracy of Apex ID was assessed through the distribution of measured values within an acceptable deviation of 0.5mm from the apical foramen. Result: The working length measured by the Apex ID machine was shorter than that measured by the periapical X-ray and the actual length of the canal (p<0.05). Within the accuracy of ±0.5mm compared to the apical foramen, the working length measured by the apex locator had an accuracy of 90%, higher than that measured by the X-ray at the rate of 80% (p<0.05). Conclusion: Apex ID apex locator has high accuracy, and can replace X-ray film in determining working length in clinical practice. Key words: working length, electronic apex locator, Apex ID, in vitro