Dental Cone Beam CT (CBCT)
What Is CBCT Used For?
Cone Beam Computed Tomography (CBCT) is a selective imaging method that provides three-dimensional sectional images of the dental and jaw region. In implant placement, impacted-tooth surgery, complex root anatomy or pathology assessment, the relative position of bone, teeth and anatomical structures can be examined.
CBCT is not routine for every patient or every dental problem. When a panoramic or periapical film is sufficient, additional tomography is not recommended. Indication depends on examination findings, the complexity of the planned procedure and the need for measurement. For simple caries treatment or routine review, CBCT is generally not required.
The Exposure Process
The exposure is usually brief; the head and jaw are kept still. Metal restorations may partly create artefacts. The scan field may be limited as far as possible to the treatment region so that unnecessary areas are not included. In pregnancy or childhood the indication is assessed with particular care.
Before the exposure, prostheses, jewellery and metal accessories may be asked to be removed. Remaining still briefly is enough to avoid motion artefact. The procedure is non-invasive; anaesthesia is not required. Turnaround time may vary by centre and review need.
Radiation and Safety
Radiation dose may vary by device, imaging field and protocol; it is not zero. A protective apron and thyroid shield may be used according to local protocol; they are assessed so as not to obstruct imaging. If a previous CBCT or film exists, the rationale for a repeat exposure is questioned. Imaging alone does not decide treatment; it is interpreted together with clinical examination.
Radiation exposure is assessed cumulatively; if other imaging was done recently, that information should be shared. Radiation exposure is not zero; if benefit is unclear, the exposure may be deferred or alternative planning methods discussed.
Clinical Use of Results
Distance to the mandibular canal, sinus-floor height, the relation of an impacted tooth to neighbouring structures and the size of a bone defect may be used in planning. Images may be shared with the surgeon, orthodontist or implant planner. The report is summarised for you in suitable language by your clinician; you can raise questions during the visit.
Digital planning software may use CBCT data for implant simulation; this may not be applied at the same level in every clinic. The image is archived and can be compared at later reviews when needed.
In cases with suspected pathology, CBCT may help assess lesion size and relation to neighbouring structures; definitive diagnosis may be established with biopsy or histopathology. In orthodontic planning, the relation of an impacted tooth to bone can be examined in three dimensions.