CBCT An Inbound Necessity In Dentistry

Write short note on CBCT.
Answer. Full form of CBCT is Cone-beam computed tomography.

It is an imaging modality which offers significant advantages for evaluation of implant patients.
CBCT was introduced to dentistry in the late 1990s and several CBCT units are commercially available for imaging of craniofacial complex.
The X-ray source and the detector are diametrically positioned and make 1800 to 3600degree rotation around the patient’s head within the gantry.
X-ray beam is collimated and resultant beam is cone or pyramid shaped. Typically, a single complete rotation, 180 to 500 basis projections of the region of interest, is generated.
Computer uses these images to generate a digital, three dimensional map of face. As this map is generated, multiplanar reconstructions i.e. axial, coronal, sagittal, or oblique sections of various thicknesses can be reconstructed from the data.
Most important feature of the various CBCT units is the field of view describing the extent of the imaged volume.
CBCT units are categorized as large field of view (greater than 15 cm), medium field of view (8 to 15 cm), and limited field of view systems (less than 8 cm).
Large field of view units image a more extensive anatomic area, deliver a higher radiation exposure to the patient, and produce lower-resolution images. Conversely, limited field of view units image a small area of the face, deliver less radiation and produce a higher-resolution image.

CBCT scans offer several advantages for evaluation of the implant patient, compared with two-dimensional (2D) imaging.
True cross sections offer a precise and detailed evaluation of the height and width of the alveolar ridge. The images can be adjusted and printed without magnification, facilitating measurements directly on the prints or films with standard rulers (i.e., not magnified).
Vertical and horizontal rulers adjacent to each section allow clinician to check for magnification and make direct measurements.
Digital format allows for image enhancement tools, rapid communication between the radiologist and the surgeon, and generation of multiple copies of the images.
Various anatomic structures can be visualized and analyzed at all three coordinate axes, so that their superoinferior, anteroposterior, and buccolingual location can be identified with precision.
CBCT images the entire arch, or even both arches, so several edentulous areas can be visualized with a single examination. The bone and soft-tissue contrast and resolution are appropriate for the diagnostic task.
CBCT scanning is a valuable imaging modality for three dimensional and cross-sectional evaluation of the implant patient.
CBCT imaging delivers much less radiation exposure to the patient.

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