[The spiral CT imaging technic--the initial experience for orthodontic examinations].

Within the course of the rapid development of CT technology, a new imaging technique, spiral computed tomography, is presently undergoing clinical testing. This procedure is based on a complete investigation of large volumes. In order to determine the suitability of this technique for the diagnostic evaluation of orthodontic problems, 25 patients were investigated. The most important advantage of this volumetric CT technique proved to be the capability of permitting complete recording of the object with only one scan, the extremely short examination time, and the associated reduction in radiation exposure, coupled with mostly improved image quality. These advantages, together with a discussion of various recording parameters and possible applications, are illustrated on the basis of typical cases. For orthodontic problems, the recording of small volumes provides the best three-dimensional surface reconstruction available at present.