Cone-Beam Computed Tomography (CBCT) is an advanced medical imaging method that produces three-dimensional images of the body. This technology is used in dentistry and other medical fields where a detailed view of hard tissues is necessary. A CBCT image provides a comprehensive perspective of bones, teeth, and their surrounding structures, allowing clinicians to diagnose conditions and plan treatments with a high degree of accuracy.
Understanding CBCT Technology
A CBCT scanner uses a cone-shaped X-ray beam that rotates around a patient’s head. In a single rotation, the machine captures hundreds of distinct images from multiple angles. This data is sent to a computer, where software reconstructs the images into a detailed three-dimensional model of the targeted area. Clinicians can then manipulate this 3D model, viewing it from any direction to examine anatomical structures without obstruction.
The cone-shaped beam covers a specific field of view that can be adjusted depending on the clinical need. This allows the scan to focus on a small area, such as a few teeth, or expand to include the entire skull. This efficiency means that high-quality diagnostic information can be obtained quickly.
Clinical Applications of CBCT
The three-dimensional images from CBCT scans are used in many areas of dentistry and medicine. For dental implant planning, these scans allow practitioners to assess the quality and volume of the jawbone. This ensures the implant can be placed in the most stable position while avoiding structures like nerves and sinuses.
In orthodontics, CBCT imaging helps evaluate the exact position of teeth, including those that are impacted or unerupted. It provides a clear view of root orientation and the relationship between the teeth and jaws. This information is used to create treatment plans for braces or aligners.
Oral and maxillofacial surgeons use these scans to plan for complex procedures. These include the extraction of impacted wisdom teeth, the assessment of jaw fractures, and the evaluation of the temporomandibular joint (TMJ).
Endodontists, who specialize in root canal therapy, use CBCT to visualize complex root canal systems that are difficult to see on standard X-rays. The technology can reveal extra canals, intricate curvatures, and small fractures within a tooth.
Some dentists and ear, nose, and throat (ENT) specialists also use CBCT to analyze the nasal cavity, sinuses, and upper airway. This helps identify issues related to conditions like sleep apnea.
The Patient Experience During a CBCT Scan
Before the scan begins, you will be asked to remove any metal objects that could interfere with the image to prevent artifacts from appearing on the final 3D image. These items include:
- Glasses
- Jewelry
- Hearing aids
- Dentures
A technician will help you get into the correct position, either sitting or standing, depending on the machine. Your head will be carefully positioned, often with a chin rest or stabilizers. It is important to remain motionless during the scan to ensure the images are clear and accurate.
The scanner’s C-arm will rotate around your head in a process that is quiet and quick, lasting between 10 and 40 seconds. The machine is open, which helps reduce feelings of claustrophobia. The procedure is painless, and you can return to your normal activities immediately after it is complete.
CBCT Scans Compared to Other Imaging
A primary distinction exists between CBCT and conventional medical CT (MDCT) scans. CBCT provides high-resolution images of hard tissues like bone and teeth, making it ideal for dental and maxillofacial applications. A medical CT is better suited for visualizing soft tissues.
An advantage of CBCT over medical CT is the lower radiation dose, as a CBCT scan exposes a patient to significantly less radiation. Scan times are also much faster with CBCT technology. This is because a medical CT uses a fan-shaped beam to capture individual “slices” of anatomy, while the CBCT scanner captures the entire volume in one pass.
Compared to standard 2D dental X-rays, the main benefit of a CBCT scan is its three-dimensional nature. Traditional X-rays produce a flat image where anatomical structures can overlap, making precise measurements difficult. A CBCT image eliminates this issue, allowing for an accurate assessment from all angles. While a CBCT scan involves more radiation than a single dental X-ray, it is still significantly less than a medical CT scan.