CONE BEAM COMPUTED TOMOGRAPHY
NEW GENERATION OF CT SCAN IN DENTISTRY
Cone Beam Computed Tomography (CBCT) scanners have been available for craniofacial three dimensional imaging in Europe since 1999 and introduced in the United States in 2001. CBCT can take both jaws in 3.6-6 seconds of actual exposure time depending on the manufacturer. This represents significantly less radiation than one would receive with a full series of digital periapical radiographs, and is relatively equivalent to bite wing radiographs.
CBCT results in real time 3-D images from every angle with high resolution, exacting and optimal detail. The compact size and low radiation dosage of the CBCT scanner, sitting position of the patient, and high level of accuracy of the 3-D images of the areas of interest, makes it ideally suited for imaging the craniofacial structures. The CBCT is reported to be accurate to approximately 0.1 mm while the medical CT scanners are accurate to approximately 0.5 + mm. The CBCT is emerging as the imaging “standard of excellence” for diagnostic and treatment planning, and patient education, in all phases of dentistry.
There are a multitude of dental indications for the use of CBCT maxillofacial imaging by the general practitioner and specialists, including evaluation of the jaws and facial bones for pathology, impactions, tumors, fractures, and developmental and congenital deformities. It is invaluable for three dimensional assessments by the restorative dentist and surgeon for combined treatment planning and use of stents. The goal is to jointly achieve restorative driven virtual implant placement with optimal emergence profile and occlusal harmony.
According to Dr. Allan Farman, current president of the American Academy of Oral and Maxillofacial Radiology, Cone Beam CT’s have high resolutions that are equivalent in dose only to a very small number of periapical radiographs. Dr. Farman also states that CBCT’s are valuable as adjuncts to periodontal, oral surgical, endodontic, and implant imaging tasks largely restricted to the treatment of adults, and “…the used stakeholders include general dentistry and most, if not all, dental specialties and allied groups.”
On November 22, 2010, the New York Times published an article, Radiation Worries for Children in Dentists’ Chairs, that requires clarification and accuracy as it affects the adult population. The following statistics were published in the Journal of the American Association comparing radiation doses measured in microsieverts:
|Survey 2D||Microsieverts||Ground Radiation|
|Full Mouth Digital (18 Films)||170.7||21 Days|
|Full Mouth D Speed Film||388||47 Days|
|Single Periapical||9.5||1.17 Days|
|Bite Wings||37.9||4.68 Days|
|*Newtom VGI||49||6 Days|
|*Newtom VG||51||6.29 Days|
|Medical Head Scan||1500|