Revolutionary Advancements In CAD/CAM Systems

Revolutionary Advancements In CAD/CAM Systems

Write a short note on CAD/CAM.
Or
Write short on CAD/CAM technique.
Answer:

The meaning of CAD/CAM is computer-aided designing and computer-aided manufacturing.

Dental copings, crowns, and fixed partial denture frameworks are machined from metal blanks via CAD/CAM.

Technique / Essentials of CAD/CAM System: It consists of 5 essentials, i.e.

1. Scanner or digitizer −virtual impression
2. Computer − virtual design
3. Milling station − produces the restoration of the framework
4. Ceramic blanks− the raw material for the restoration
5. Furnace − for post-sintering, cramming, etc.

Scanner of CAD/CAM System:

• Dimensions of the prepared tooth are picked up and digitized to create a three-dimensional image of a prepared tooth in a computer.
• Scanning and preparation of dye is done. Scanners are of two types, i.e. contact probes and scanners.

Computer or CAD Process:

• Either the restoration or the core is designed in the computer.
• Manufacturers consist of their own software for the CAD process.
• CAD process aids in designing the restoration, coping, or the FDP substructure. The computer automatically detects the finish line.
• Recording of bite registration is also added to the data.
• All the information with 3D optical impression of the prepared tooth establishes an approximate zone in which new restoration can form.
• Formed restoration is morphed to fi in this zone in an anatomically and functionally correct position.

Milling Station of CAD/CAM System:

Signals from the computer control the milling tool which shapes the ceramic block as per the computer-generated design. For starting this ceramic block is attached to the machine with the help of a frame or built-in handle. Milling is done by a diamond or carbide milling tool.

Ceramic Blanks of CAD/CAM System:

For milling a variety of ceramic blanks are available in various sizes, shapes,s, and shades. If the blank is larger multiple units are produced. Smaller blanks can produce a single coping or restoration. The ceramic blank is attached with the help of a frame to the machine or by one or more handles on the blank itself.

Furnace of CAD/CAM System:

Furnaces are available based on the type of blank used. The furnace for the sintering of zirconia is highly specialized as it uses very high temperatures. Sintering of zirconia involves a temperature greater than 1500°C.

Advantages of CAD/CAM System:

• Fit is improved.
• It is very strong.
• In some systems, scanning can be done in the mouth, so there is no need to take impressions.
• Single-visit prosthesis delivery is possible.
• Formed structures are homogenous with minimum porosity and defects.
• Complex castings, i.e. full arch fixed partial dentures, overdenture frames, and partial denture frames are manufactured with great ease and accuracy.
• Laboratory equipment can be decreased as the equipment involved with metal casting and processing is not required.
• Since it copies the original form of the tooth, it can produce the restoration that duplicates the original tooth.

Disadvantages of CAD/CAM System:

• It is very costly.
• Scanning of preparation is technique sensitive.
• It is still not as strong as PFM restorations.
• In the case of zirconium core ceramics, there is the problem of chipping of veneering ceramics.