CONE BEAM COMPUTED TOMOGRAPHYSmall Cone Big Scoop

INTRODUCTION Cone beam computed tomography is recent advancement in diagnostic

imaging which has bigen to emerged as a potentially low dose imaging

techniques for visualization of bone pathologies

HISTORY July 1, 1956 as CFCY-TV, under the ownership of the Rogers family and their company

Family patriarch Col

rebroadcaster in Charlottetown in 1972

HISTORYCone beam technology was first introduced in the European market in 1996 by QR s.r.l. (NewTom 9000) and into the US market in 2001.[2]

October 25, 2013, during the "Festival della Scienza" in Genova, Italy, the original members of the research group: Attilio Tacconi, Piero Mozzo, Daniele Godi and Giordano Ronca received an award for the cone-beam CT invention, a revolutionary invention that changed world's dental radiology panorama.[5][6][7]

CBCT USE IN IMPLANTOLOGYA dental cone beam scan offers invaluable information when it comes to the assessment and planning of surgical implants. The AAOMR also suggests cone-beam CT as the preferred method for presurgical assessment of dental implant sites.

CBCT USE IN ORTHODONTICSAs a 3D rendition, CBCT offers an undistorted view of the dentition that can be used to accurately visualize both erupted and non-erupted teeth, tooth root orientation and anomalous structures that conventional 2D radiography cannot.

Processing example using x-ray data from a tooth model:

DISADVANTAGES OF CBCT TECHNOLOGYThere are a number of drawbacks of CBCT technology over that of medical-grade CT scans, such as increased susceptibility to movement artifacts (in first generation machines) and to the lack of appropriate bone density determination

ADVANTAGES OF CBCT TECHNOLOGYCBCT is well suited for imaging the craniofacial area. It provides clear images of highly contrasted structures and is extremely useful for evaluating bone. The use of CBCT technology in clinical practice provides a number of potential advantages for maxillofacial imaging compared with conventional CT:

X-ray beam limitation: Reducing the size of the irradiated area by collimation of the primary x-ray beam to the area of interest minimizes the radiation dose. Most Cone Beam CT units can be adjusted to scan small regions for specific

diagnostic tasks. Others are capable of scanning the entire craniofacial complex when necessary.

Image accuracy: The volumetric data set comprises a 3D block of smaller cuboid structures, known as voxels, each representing a specific degree of x-ray absorption. The size of these voxels determines the resolution of the image. In conventional CT, the voxels are anisotropic rectangular cubes where the longest dimension of the voxel is the axial slice thickness and is determined by slice pitch, a function of gantry motion. Although CT voxel surfaces can be as small as 0.625 mm square, their depth is usually in the order of 1–2 mm. All CBCT units provide voxel resolutions that are isotropic equal in all 3 dimensions. This produces sub-millimetre resolution (often exceeding the highest grade multi-slice CT) ranging from 0.4 mm to as low as 0.125 mm (Accuitomo).

Rapid scan time: Because Cone Beam CT acquires all basis images in a single rotation, scan time is rapid (10–70 seconds) and comparable with that of medical spiral MDCT systems. Although faster scanning time usually means fewer basis images from which to reconstruct the volumetric data set, motion artifacts due to subject movement are reduced.

INDICATION

The aim of this study was to identify specific indications for dental cone-beam computed tomography (CBCT) in the field of oral and maxillofacial surgery. To this end, we compared the efficacy of CBCT to that of panoramic radiography, the standard imaging modality, for the evaluation of different surgical questions in the oral and maxillofacial region. Dentall CBCT proved to be particularly useful in cases where visualization of a second plane is necessary for implant planning or for pre-surgical evaluation of retained and displaced teeth posing a risk to adjacent structures. It is also indicated for precise localization of luxated teeth and dental implants dislocated into surrounding areas, localization of the mandibular canal to assess its anatomical relationship to overfilled root canal filling materials, assessment ofthe extent of osseous lesions, and evaluation of patients with suspected mandibular or condylar fractures. The main advantages of CBCT are reduction of the risks of surgery due to the free selection of imaging planes, maindibular canal marking, 1:1 magnification, and the ability to use DICOM data in other implant or surgical planning software. Adequate user experience is important for proper evaluation of dental CBCT scans, as is the diagnosis of incidental findings falling into areas not primarily related to dentistry and therefore requiring additional investigation.