Radiographic length determination

X-ray measurement on tooth 46; three root canals

The X-ray length determination is a dental technique for determining the root canal length during a root canal treatment .

Here, an X-ray image of the tooth to be treated is taken while there is a radiopaque object in it, for example a Hedstrom file or a silver pin that was inserted up to the assumed or tactile working length. In this way, the correspondence of the assumed working length with the radiological root tip can be determined, which, however, does not necessarily have to match the anatomical root tip due to the projection of a three-dimensional structure into a two-dimensional plane. The endodontic apex (also physiological apex), a retraction of the pulp, is approx. 1–2 mm in front of ( coronal ) the anatomical apex.

Due to the instrument protruding from the root canal and the rubber dam that is often used in root canal treatment , an X-ray cannot be made using the parallel technique, which requires the tooth to be exposed to be bite onto the film holder. Instead, the half-angle technique is used .

The determination of the working length with the help of X-ray technology is the most common method because of its relatively low cost. Endometry , an electrometric length determination, provides more precise measurement results .

Individual evidence

1. ^ Lehmann, Klaus M., Elmar Hellwig: Zahnärztliche Propädeutik . 10th edition. Urban & Fischer at Elsevier, 2005, ISBN 3-437-05391-4 , p. 193 f .