Dental CT was introduced in 1987. In dental CT, axial scans of the jaws are acquired using the highest possible resolution, and curved as well as orthoradial multiplanar reconstructions are obtained. The coronal plane is not generally used for the scans in dental CT, since the metal artefacts from teeth fillings and other metal-dental work are frequent and appear in these sections. Using the axial planes, the occlusion plane will still have the artefact displayed, but the bone will be left undistorted.
Dental CT can be performed with a conventional CT, a spiral CT or a multislice CT scanner. The device should give high-resolution scans with a small focal spot and the acquired slices should be of 1.5mm thickness. The slower the rotation of the tube, the more detailed is the information gained. In order to achieve routine images of the jaws, a spiral scan technique of 1 s per rotation is valid, if small details need to be obtained for diagnostic purposes, then 2 s per rotation need to be used.
TECHNIQUAL DETAILS
The standard protocol for dental CT in the diagnosis of pathologic conditions is as follows: Incremental scan type, 1.5mm slice thickness, 1.0 table feed; 120mm field of view (for the mandible); 100mm field of view (for the maxilla); 2 s scan time; 512 matrix; 12 kV; 25–100m A; high-resolution edge enhanced filter, 20001400HU (Hounsfields units) bone window; mandible base and hard palate as scan planes . After the examination is completed, the axial slices are transferred to a workstation to perform multiplanar reconstructions; this is accomplished through dental software.
REF : Endodontic Topics 2004, 7, 52–72
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