Ch 31 Three-Dimensional Imaging

What is CBCT and its uses?

• CBCT: Uses CT technology specifically adapted for dental imaging.

• Uses: Provides 3D views but doesn’t replace regular 2D X-rays.

Purpose of CBCT

• Oral Health: Designed to aid in general and specialized dental care.

• Flexibility: Many CBCT machines can switch between 2D and 3D.

CBCT Radiation Dose

• Higher Radiation: CBCT uses more radiation than 2D images.

• Categories of Use: Divided into necessary, preferred, or optional based on benefits.

How CBCT Works

• 360° Scan: A fan-shaped X-ray beam rotates around the head, capturing data.

• Data Processing: Up to 2,000 receptors create a detailed image.

Positioning and Beam Shape

• Position: Patient sits or stands upright.

• Cone Beam: X-ray beam shape limits radiation to the dental area only.

3D and 2D Display Options

• Output: Images can be shown as either 3D or 2D.

• Benefit: Flexibility for different viewing needs.

Field of View (FOV) Control

• FOV Sizes: Large, medium, or focused view options.

• Radiation Control: Matches FOV to the area of interest, keeping radiation low.

Voxels (Volume) for 3D Imaging

• Voxel: 3D pixel that captures depth.

• Result: Provides clearer and more detailed images.

CBCT Anatomical Planes

• Planes: Axial (top/bottom), Sagittal (left/right), Coronal (front/back).

• Purpose: Allows for a full 3D view in slices or whole image.

3D Imaging in Dental Implants

• Function: Helps locate nerves and plan implants.

• Views: Axial, cross-sectional, panoramic, and 3D for implant assessment.

Orthodontic and Endodontic Uses

• Ortho: Tracks teeth position and growth.

• Endo: Finds hidden issues like impacted teeth or infections.

As Low As Reasonably Achievable Principle

• Radiation Safety: CBCT should only be used when benefits outweigh the radiation risks.

• Comparison: CBCT has higher radiation than standard panoramic X-rays.

Cone-beam computed tomography Image Interpretation

• Volume of Data: Each scan produces around 1,500 image slices.

• Challenge: Detailed review is time-consuming and requires expertise.

Comprehensive Interpretation Needs

• Beyond Teeth: CBCT can show nasal passages, sinuses, and jaw structure.

• Expert Review: Often done with help from a maxillofacial radiologist.