A dental CT scan, formally known as Cone-Beam Computed Tomography (CBCT), offers a highly detailed, three-dimensional (3D) view of the oral and maxillofacial structures. This technology is a significant advancement over traditional two-dimensional (2D) X-rays, such as panoramic films, which flatten structures and obscure anatomical details due to overlapping shadows. CBCT uses a cone-shaped X-ray beam that rotates around the patient’s head, capturing hundreds of images that a computer reconstructs into a volumetric data set, allowing professionals to view teeth, bone, soft tissues, and nerve pathways from any angle.
Visualizing Bone Structure for Surgical Planning
The application of dental CBCT is to provide a precise map of the patient’s jaw for planning invasive procedures. The scan reveals information about bone quality and quantity, which is relevant for the successful placement of dental implants. It allows the clinician to accurately measure the available bone height, width, and density, providing a reliable assessment of the bone volume needed to support an implant fixture and determine the appropriate surgical technique.
The 3D visualization is necessary for identifying and precisely locating adjacent anatomical structures, which maximizes patient safety during surgery. In the lower jaw, the CBCT scan clearly maps the path of the inferior alveolar nerve, ensuring the planned implant trajectory avoids this sensory pathway. For the upper jaw, the scan accurately delineates the boundaries of the maxillary sinuses and the nasal cavity floor, preventing potential complications like sinus perforation.
The volumetric data enables a process known as virtual surgery, where the entire procedure is simulated on a computer before the patient is in the chair. This virtual planning allows for the optimal position and angulation of the implant to be determined, ensuring the best prosthetic outcome. The digital plan can then be used to create a custom surgical guide, which is a template that fits over the patient’s teeth or gums and dictates the exact depth and angle of the drill during the actual surgery. This guided approach transforms a freehand procedure into a highly predictable and accurate one.
Identifying Subtle Pathology and Infection
The diagnostic capability of the CBCT scan is employed to detect conditions that are difficult or impossible to see on 2D radiographs. The scan is sensitive at identifying fine vertical root fractures, which are hairline breaks that run down the length of the tooth root. Since traditional X-rays struggle to show these fractures due to the superimposition of surrounding bone, CBCT’s multi-planar views provide the clarity necessary to visualize the separation of the root segments.
The detailed imaging provides a more accurate assessment of periapical lesions, which are areas of bone destruction caused by infection at the root tip. Unlike 2D images that only show an approximation, CBCT accurately measures the true size and extent of the bone loss in three dimensions. This allows for a more precise diagnosis and a better understanding of the prognosis before treatment begins.
For larger bony lesions, such as jaw cysts or benign tumors, the CBCT scan is necessary for precisely delineating their borders and determining their relationship to surrounding structures. This clear visualization of the extent of the pathology is a foundational step in planning the correct surgical removal or monitoring approach. Without the 3D map, a clinician risks either incomplete removal or unnecessary damage to adjacent healthy tissue.
Guiding Specialized Dental Procedures
Beyond surgical planning, CBCT scans provide detailed anatomical information for the success of specialized procedures. In endodontics, the field of root canal treatment, the scan reveals the complex internal anatomy of the tooth. It can identify the exact number, shape, and curvature of the root canals, including extra canals, such as the second mesiobuccal canal in maxillary molars, that are often missed on standard X-rays.
The CBCT also helps to locate calcified canals, which are narrowed or obstructed pathways challenging to navigate during a root canal procedure. This pre-treatment mapping reduces the risk of procedural complications, such as instrument breakage or accidental perforation of the root. The scan is also used to precisely locate the position of foreign bodies, such as fractured instrument fragments, within the root canal system or surrounding jawbone.
For orthodontic treatment, CBCT offers a view of the craniofacial skeleton and the dentition, which is necessary for complex case management. It provides an accurate assessment of the relationship between the teeth and their supporting bone structure, including the thickness of the cortical bone plates. This is helpful for assessing impacted teeth, like wisdom teeth or canines, by clearly showing their exact 3D position and proximity to adjacent tooth roots and nerves. The detailed visualization assists in planning complex tooth movements and determining the precise placement sites for temporary anchorage devices used in advanced tooth positioning.