Dental CT imaging: A look at the jaw

The jaw comprises two complex bony structures: the mandible and maxilla. Their curved or archlike configuration makes radiographic imaging difficult. Furthermore, the superimposition of dense teeth and roots may obscure underlying tissues, and streak artifacts from dental restorations often degrade computed tomographic (CT) images. Recently, dental CT reformatting programs that use thin transverse images of the jaw to reformat mu!tiple panoramic and cross-sectional views were developed. Since images are reformatted, streak artifacts that degrade bone visualization at direct coronal CT are projected over the crowns of the teeth, permitting optimal viewing of bone. As a result, these programs have been successfully used to evaluate implants, cysts, tumors, and surgical procedures. They have created not only a new modality for viewing the jaw but also a new partnership between dentists and radiologists. Questions that cannot be answered in the dentist's office with conventional radiographs are now answered in radiology departments with dental CT scans. The objective of this article is to trace, with a series of examples, the effect that this imaging modality has had on radiographic evaluation of the jaw and to provide the reader with knowledge that should enable him or her to become more involved in imaging of the jaw.