Cone Beam CT Technology

Available in Europe since1999 and introduced in the United States in 2001, Cone Beam CT (CBCT) is a relatively new imaging technology that generates a 3D volume of image data. Using a cone-shaped x-ray beam rather than the linear fan beam of conventional CT, a CBCT scanner takes just one revolution around the patient to capture these multi planner views. CBCT can take both jaws in 3.6-6 seconds of actual exposure time. This represents significantly less radiation than one would receive with a full series of digital periapical radiographs, and is relatively equivalent to bite wing radiographs. With imaging software, the data may be reconstructed to render 3D views that can be manipulated to show different angles, varying depths and thicknesses, and be selective for certain tissues. The dose of radiation needed for a CBCT is much lower than for a conventional CT.

CBCT Applications

Implantology:

3D CT scans allow the surgeon and restorative dentist to optimally plan and place dental implants. Their uses and benefits are present throughout the continuum of care from diagnosis to treatment to post-op examinations and include:

  • Locate and determine the distance to vital anatomic structures
  • Measure alveolar bone width and visualize bone contours
  • Determine if a bone graft or sinus lift is needed
  • Select the most suitable implant size and type
  • Optimize the implant location and angulation
  • Increased case acceptance
  • Reduced surgery time
  • Build patient confidence

And with the use of guided implant placement based on 3D CT scans, all the above benefits are enhanced to the point that the surgeon can approach each case with the confidence that comes from knowing that the best available image data and technology have been used to ensure success.

Orthodontics:

Orthodontics has traditionally relied on 2-dimensional x-rays in evaluating 3-dimensional structures. With Cone Beam CT imaging, a more comprehensive orthodontic diagnosis and more accurate treatment planning is possible by allowing for:

  • 3D views of vital structures
  • 3D evaluation of impacted tooth position and anatomy
  • TMJ assessments of condylar anatomy in three dimensions
  • Orthognathic surgery treatment planning and growth assessments in true 1:1 imaging
  • Airway assessments
  • Planning for placement of dental implants for tooth restoration or orthodontic anchorage and for placement of temporary anchorage devices (TADs)
  • Assessment skeletal symmetry or asymmetry
Impactions:

Cone Beam CT scans can provide a more accurate and 3-dimensional assessment to provide more predictable treatment results while reducing the risks associated with any impacted tooth.

  • Visualize an impacted tooth’s position in relation to surrounding vital structures and nearby teeth and their roots
  • Better assess the risk of treatment or non-treatment based on more accurate 3-dimensional analysis
Sinus And Airway Studies

Volumetric data obtained from a CBCT survey can be used to visualize the sinuses and the entire airway path from the nasal and oral entrances to the laryngeal spaces for:

  • Identification of anatomical borders
  • Determination of degree of infection and presence of polyps
  • Assistance in airway studies for diagnosis and treatment of obstructive sleep apnea
  • Calculation of actual volume of airway space
  • Determination of the point of airway constriction
Pathology:

CBCT scans provide a superior means of visualizing and studying pathological processes in the maxilla and mandible. This information is invaluable when planning any surgical efforts for biopsy or resection. The data can be used to:

  • Render three-dimensional images of hard tissue abnormalities
  • Provide more accurate information related to size, extent, location, and the relation to and effect on nearby anatomical structures
  • Monitor the progression of the pathology as well as the success of treatment with the use of multiple scans
Endodontics:

Although conventional radiography is more practical and better suited for everyday endodontic procdures, volumetric data from CBCT scans can provide serial axial, coronal, and sagittal views that are not possible to obtain from conventional radiography. The ability to reduce or eliminate superimposition of surrounding structures makes it easier to visualize areas of interest in three dimensions. This provides much clinically relevant diagnositic information and has many potential applications for endodontics including:

  • More accurate identification and diagnosis of periapical endodontic pathosis than conventional radiography
  • Visualization of obscure internal pulpal anatomy and root canal systems
  • Assessment of internal and external root resorptive processes
  • Identification of root fractures and other areas of trauma
  • Volumetric and density comparisons of periradicular bone following endodontic treatment in order to assess the degree of success or failure
  • Pre-surgical planning
TMJ:

Accurate evaluation of the temporomandibular joint (TMJ) has been difficult due to the superimposition of other structures in conventional radiographs. With Cone Beam CT imaging, it is now possible to:

  • Assess the condylar anatomy of the TMJ without superimposition and distortion of the image
  • Obtain a true 1:1 imaging of the condylar structures for more accurate assessments
Periodontics:

The disadvantages of conventional 2-dimensional x-rays for accurate periodontal assessment is avoided by 3-dimensional and cross-sectional analyses helping to avoid surprises often encountered during periodontal surgery.

  • Analyze periodontal bone defects on all sides of every tooth
  • Assess the extent of every furcation involvement
  • Track the progression of advancing periodontal bone loss
  • Treatment plan dental implants by evaluating bone parameters such as bone width, depth, and density
  • Visualize vital structures such as the maxillary sinus, mental foramen and mandibular nerve prior to periodontal or implant surgeries
Oral Surgery:

In addition to implant placement, a Cone Beam CT scan is an invaluable diagnostic and treatment planning tool for the oral surgeon for:

  • Determine the precise three-dimensional position of a tooth within the alveolar bone and how this position relates to vital structures for extractions and impactions
  • Visualize hard and soft tissues on the computer in three dimensions for planning maxillofacial surgeries
  • Generate life-size CAD-CAM stereolithic (STL) models for surgical planning and preparation
  • Monitor skeletal changes, airway changes, and healing responses