Cone-beam Computed Tomography (CBCT)

By Tianyi Zhang

In 1972, Hounsfield, along with Cormack, transformed the history of medical imaging by introducing Computed Tomography (CT) scanner to medical practices. He was awarded The Nobel Prize in Physiology in 1979. This discovery showed us that the acquisition of cross-sectional slice imaging of an object is possible, which enables us to view the internal structure of body parts without dissection. However, size, high cost, high dose of radiation were among some of the drawbacks for the utilization of CT.

Yoshinoro Aria in Japan and Piero Mozzo in Italy developed Cone-beam Computed Tomography(CBCT) in later 1990s. CBCT first became commercially available in US in 2001. It won great popularity in oral and maxillofacial imaging. During imaging acquisition, the scanner rotates around patient’s head to obtain 150-599 unique radiographic views. The scanning time is between five to forty seconds depending on the regions. After acquisition, the scanning software reconstructs raw image data into three-dimensional format with diagnostic value.

Robert S Ledley, class of 1949 NYU Dental graduation photo. Inventor of the Whole-body CT Scanner. (Sittig et al.)

Cone-beam computed tomography has been widely used in the field of medicine and dentistry. CBCT brings revolution in extraoral imaging due to its compact size, rapid scanning time, low cost and low ionizing radiation properties compared to traditional medical CT. Since its introduction to dentistry, CBCT has completely changed the scope of diagnosis in its subfield including periodontics, implant dentistry, endodontics, oral and maxillofacial surgery and TMJ imaging.

The application of CBCT in oral and maxillofacial surgery is significant. CBCT is used to evaluate the position of impacted wisdom teeth, benign or malignant tumors, periapical bone lesions, locations of jaw abnormalities, metal fragments from traumatic accidents and small calcifications. CBCT’s feature of combining multiple 2D image slices makes it possible to overcome superimposition and achieve better distance calculation. The utilization of CBCT has enabled much improved efficiency for diagnosis, treatment, and prognosis of oral maxillofacial pathology.

The successful completion of endodontic treatment cannot be separated from good imaging technique. CBCT indicates its potential in this field. It can be used to detect complicated root morphology, number of roots, lateral and accessory canals, to confirm working length. CBCT has also been proved for its superiority in detecting inflammatory root resorption in its early stages compared to conventional 2D radiographs. In the event of dental trauma, CBCT could also aid the proper diagnosis and treatment.

CBCT also has broad application in the field of periodontics. CBCT allows for accurate measurement of bone level and bone morphology. Implant dentistry’s success relies on not only the clinician’s skill, but also the qualitative and quantitative measurement of bone. With CBCT’s virtual guidance, clinicians now are able to better plan and place implants.

Interests towards CBCT utilization has been growing especially in the field of dentistry. CBCT gives us detailed insights into anatomical structures. However, CBCT should still be prescribed with caution and follow ALARA rules. CBCT is only justified when 2D radiographs cannot provide sufficient information.

Citation:

Kumar M, Shanavas M, Sidappa A, Kiran M. Cone beam computed tomography-know its secrets. J Int Oral Health. 2015;7(2): 64-68.

Venkatesh E, Elluru SV. Cone beam computed tomography: basics and applications in dentistry. J Istanb Univ Fac Dent.2017;51(3 Suppl 1): S102-S121.

Jacobs R, Salmon B, Codari M, Hassan B, Bornstein MM. Cone beam computed tomography in implant dentistry: recommendations for clinical use. BMC Oral Health.2018;18:88.

Dean F. Sittig, Joan S. Ash, Robert S. Ledley. The Story Behind the Development of the First Whole-body Computerized Tomography Scanner as Told by Robert S. Ledley. J Am Med Inform Assoc. 2006 Sep-Oct; 13(5): 465–469. doi: 10.1197/jamia.M2127 Robert S Ledley, class of 1949 NYU Dental graduation photo. Inventor of the Whole-body CT Scanner. (Sittig et al.)