Although the reliability of the electronic apex locator is agreed upon in the endodontic literature, the general practitioner has difficulties to integrate the device in his daily practice. The authors of this paper conclude that the apex locator should be used to confirm the information obtained from the pre-operatory radiograph (imperatively taken with the parallel technique) and they assert that the data obtained electronically have still to be interpretated. The apex locator can be considered an essential tool as long as its limitations are known.