What is a CBCT in dentistry?
Dental cone beam computed tomography (CT) is a special type of x-ray equipment used when regular dental or facial x-rays are not sufficient. Your doctor may use this technology to produce three-dimensional (3-D) images of your teeth, soft tissues, nerve pathways, and bone in a single scan.
CBCT images have been shown to be successful for various clinical uses, including oral and maxillofacial surgery, orthodontic and endodontic therapies (Small FOVs), and implant planning and placement.
CBCT technology may be used by general dentists and specialists to improve diagnosis and treatment planning in the following cases:
- Location of anatomic structures: mandibular canal, submandibular fossa, incisive canal, maxillary sinus.
- Size and shape of ridge, quantity, and quality of bone.
- Number and 3D orientation of implants.
- Length and diameter of planned implants.
- Need for bone graft, sinus lift.
How does the procedure work?
During a cone beam CT examination, the C-arm or gantry rotates around the head in a complete 360-degree rotation while capturing multiple images from different angles that are reconstructed to create a single 3-D image.
The x-ray source and detector are mounted on opposite sides of the revolving C-arm or gantry and rotate in unison. In a single rotation, the detector can generate anywhere between 150 to 200 high resolution two-dimensional (2-D) images, which are then digitally combined to form a 3-D image that can provide your dentist or oral surgeon with valuable information about your oral and craniofacial health.
There is increasing use of CT (computed tomography) scans in dentistry, particularly to plan dental implants; there may be significant levels of radiation and potential risk. Specially designed CBCT (cone beam CT) scanners can be used instead, which produce adequate imaging with a stated tenfold reduction in radiation. Although computed tomography offers high-quality images and accuracy, the radiation dose of the scans is higher than the other conventional radiography views, and its use should be justified Controversy surrounds the degree of radiation reduction though as the highest quality cone beam scans use radiation doses not dissimilar to modern conventional CT scans.
Cone-beam computed tomography
Cone-beam computed tomography (CBCT), also known as digital volume tomography (DVT), is a special type of X-ray technology that generates 3D images. In recent years, CBCT has been developed specifically for its use in the dental and maxillofacial areas to overcome the limitations of 2D imaging such as buccolingual superimposition. It is becoming the imaging modality of choice in certain clinical scenarios although clinical research justifies its limited use.
- Assessment of unerupted and/or impacted teeth
- Assessment of external resorption
- Assessment of cleft palate
- Treatment planning for complex maxillofacial skeletal abnormalities
- Restoration of dentition (if conventional imaging is inadequate).
- Assessment of infra-bony defects and furcation lesions
- Assessment of root canal anatomy in multi-rooted teeth.
- Treatment planning of surgical endodontic procedures and complex endodontic treatments.
- Assessment of dental trauma.
Indications of CBCT, according to the SEDENTEXCT (Safety and Efficacy of a New and Emerging Dental X-ray Modality) guidelines include.
- Assessment of lower third molars where an intimate relationship with the inferior dental canal is suspected.
- Assessment of unerupted teeth.
- Prior to implant placement.
- Assessment of pathological lesions of the jaws (cysts, tumors, giant cell lesions, etc.).
- Assessment of facial fractures.
- Treatment planning of orthognathic surgery.
- Assessment of bony elements of the maxillary sinus and TMJ.