[Determination of tooth length in endodontics]

Determination of the exact tooth length and subsequent working length remains a corner stone of proper endodontic treatment. Up to now, no system has proven to provide the exact location of the apical constriction under all circumstances. Several possibilities of determining tooth length are discussed. Factors influencing the outcome of the different techniques are described. A simple and rather accurate way for calculating tooth length on X-rays is elaborated. Apparently, electronic devices are becoming increasingly accurate, and may become a challenge for the radiographic tooth length determination. Actually, dentists have most of all to rely on X-rays for tooth length determination.