Value of two cone-beam computed tomography systems from an orthodontic point of view

Since its introduction in dental radiology in 1998, cone-beam computed tomography (CBCT) has found increasing acceptance in clinical routine. The aim of this study was thus to evaluate this imaging modality from an orthodontic point of view.

Two systems formed the basis of this investigation: the NewTom 9000 (NewTom Germany AG, Marburg, Germany), in use at the University Medical Center Hamburg-Eppendorf since October 2002, and the mobile Arcadis Orbic 3D system (Siemens Medical Solutions, Erlangen, Germany), which was introduced in February 2005. Two independent examiners evaluated a total of 68 NewTom and 15 Arcadis Orbic 3D images involving orthodontic indications. The images were categorized according to their indications and diagnostic value assessed according to a predefined and quantifiable protocol. Information obtained from the CBCT was also compared to that gleaned from conventional radiographs.

The indication for the NewTom images in cleft patients as well as for all Arcadis Orbic 3D images was considered justified. The osseous morphology of the cleft and position of osteosynthetic screws and plates were particularly well visualized. CBCT implementation in cases of tooth impaction or for assessing third molars was considered justified, although its value was judged differently by the two examiners. CBCT did not provide more information than conventional imaging regarding cartilaginous joint structures.

In complex orthodontic cases in which 3D imaging is mandatory, CBCT is the method of choice. Furthermore, in cleft patients and those undergoing combined orthodontic and maxillofacial therapy, CBCT proved advantageous, providing more information than conventional images.