CONE BEAM COMPUTED TOMOGRAPHY
Radiology is important in the diagnostic assessment of the dental patient and guidelines for the selection of appropriate radiographic procedures for patients suspected of having dental and maxillofacial disease are available.
The American Academy of Oral and Maxillofacial Radiology (AAOMR) has established “parameters of care” providing rationales for image selection for diagnosis, treatment planning and follow-up of patients with conditions affecting the oral maxillofacial region, including temporomandibular joint (TMJ) dysfunction , diseases of the jaws and dental implant planning. Although combinations of plain x-ray transmission projections and panoramic radiography can be adequate in a number of clinical situations, radiographic assessment may sometimes be facilitated by multiplanar images including cone beam computed tomography (CBCT).
Cone Beam Computed Tomography (CBCT) systems have been designed for imaging hard tissues of the maxillafacial region. CBCT is capable of providing submillimetre resolution in images of high diagnostic quality, with short scanning times (10-70 seconds) and radiation dosages reportedly up to 15 times lower than those of conventional CT scans. CBCT allows the creation in “real time” of images not only in the axial plane but also 2-dimensional (2D) images in the coronal, sagittal and even oblique or curved image planes — a process referred to as multiplanar reformation (MPR). In addition, CBCT data are amenable to reformation in a volume, rather than a slice, providing 3-dimensional (3D) information.
The clinically significant advantages of CBCT are:
● CBCT provides distortion free images of the teeth and jaws which confirm to the "1:1 or True size" sections that enable accurate measurements
● Higher hard tissue resolution (0.07mm to 0.5mm) compared to a best of 0.3mm-0.5mm resolution by spiral CT (~ 64-Slice scanner) making CBCT relevant for dental implant placement, endodontic and periodontal diagnosis.
● Many fold (up to 15 times) reduction in radiation exposure for the patient compared to spiral CT and approx. 2-3 times greater exposure than a single Panoramic radiograph (OPG)
● Further reduction in patient exposure can be achieved by use of selectable scan size / volume (Field of View - FOV) i.e. one jaw / one quadrant / one TMJ / both jaws / jaws & sinus etc programs available with all hybrid (1st / 2nd Gen) CBCT scanners.