CAD-CAM Systems in Dentistry

CAD-CAM Systems in Dentistry

• CAD-CAM stands for Computer-Aided Design and Computer-Aided Manufacturing, a chain process used for creating indirect dental restorations.
• Traditional methods are time-consuming, have a higher chance of errors, and are more dependent on technician skills.
• CAD-CAM systems are less time-consuming, easier to process, reduce errors, and are more accurate, but depend on software.
• The process involves a scanning phase (data acquisition), a design phase, and a milling phase.

Scanning Phase

• Data Acquisition: This phase involves obtaining a digital representation of the patient's teeth for creating a digital model.
• Types of Scanners:
  • Optical scanners (laser/light scanners) use triangulation. A light source and camera produce a 3D image.
  • Mechanical scanners use a touch probe to mechanically scan the model with a ruby ball. This technique is highly accurate.
• Intraoral Scanning: Direct scanning of teeth intraorally. This is technique sensitive and prone to adjacent teeth/gingiva/salivary interference which can produce registration difficulties at margins.
• Extraloral Scanning: Scanning of dental models or impressions.
• Clinic/Lab Systems: Scanning can occur in the clinic (intraoral) or the lab (model/impression scanning).

Designing Phase

• Software Usage: Specialized dental software creates a Standard Tessellation Language (STL) file, a digital model of the dental restoration.
• Software Examples: ExoCAD, Blender, MeshMixer, MeshLab.

Milling Phase

• Milling Devices:
  • 3-axis milling devices, 4-axis devices, and 5-axis devices.
  • Different models offer variations in axes movements which impact production quality and cost.
• Milling Types:
  • Dry-milling: Suitable for soft materials not prone to chipping. Examples: Zirconia, PMMA, CoCr.
  • Wet-milling: Essential to avoid overheating, ideal for materials susceptible to degrading. Often used for materials like Cobalt-chrome.
• Advantages and Disadvantages of Milling: Certain milling materials yield benefits like lower costs however may result in higher shrinkage during sintering, development of microcracks, or surface defect formations.

Materials for CAD-CAM

• Ceramics: Zirconia, Porcelain.
• Metals: Titanium, Cobalt-chrome.
• Polymers: Polymethyl methacrylate (PMMA) , Polyether-ether ketone (PEEK).
• Materials Availability: Materials can be supplied as blanks, partially sintered blocks, or completely sintered blocks.

Uses of CAD-CAM

• Fixed Restorations: Inlays, onlays, overlays, crowns, bridges, and veneers.
• Removable Prostheses: PMMA dentures, metallic frameworks, and surgical guides.

Advantages of CAD-CAM

• Reduced chair time, and appointments.
• Enhanced accuracy and precision.
• Improved retention.
• Digital archiving.
• Reduced use of traditional impression methods.
• Improved cross-infection control.

Disadvantages of CAD-CAM

• High initial cost.
• Potential material waste.
• Wear in milling tools.
• Chairside CAD-CAM procedures might be time-consuming.
• Methods to overcome the high cost - are 3D printing and recycling of waste.

Explore the advanced technology behind CAD-CAM systems used in dentistry to create precise and efficient indirect dental restorations. This quiz covers the scanning phase, types of scanners, and the advantages of CAD-CAM over traditional methods. Test your knowledge on the essential processes involved in digital dentistry!