Dental CAD/CAM – All You Need to Know

CAD/CAM dentistry: 

as its name implies, is a discipline of dentistry which use CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) systems to improve the design and fabrication of dental restorations.

It can be used in the design and construction of veneers, implant abutments, crowns, inlays, onlays, fixed partial dentures and full-mouth reconstruction. Also, we can use CAD/CAM in orthodontics. But in dentistry specifically, it was only used for the first time a decade after its creation. In the 1960s, this technology was used in the aircraft and automotive industries.

Advantages:

• The quality of CAD/CAM restorations is high and they have a natural appearance because the ceramic blocks emulate enamel.

• The measurements and fabrication are precise.
• If there’s a milling machine in a dental office, patients could receive their permanent restoration the same day, and there is no need for a second appointment. (These savings in time and labor have the potential to reduce costs, too.)
• Digital scans are faster and easier than conventional impressions because wax-ups, casting, firing, and investing are eliminated.
• Precision in the adaptation of the teeth with an exact marginal dental sealing which ensures its long-term performance.
• Dentists know exactly where they should place the implants.

Disadvantages:

• The initial cost of software and equipment is high.
• High barrier of entry in terms of technical proficiency required. 

All CAD/CAM systems consist of three components:

1. Computerized Surface Digitization Using Scanners.

Geometry is transformed into digital data which can be processed by a computer. The data acquisition involves making an optical impression of the preparation. We can do so with the help of:

• 3D surface digitizing or scanning methods, which we can separate into:
  • Direct (at the tooth)
  • Indirect (via impression making and model fabrication)
• Various surface digitization techniques, such as:
  • Laser scanning
  • Ultrasound
  • Magnetic resonance imaging
  • Computed tomography
  • Contact profilometry

A scanner in dentistry refers to a data collection device which measures three dimensional jaw and tooth structures to transform them into digital data sets.

 types:

• Optical Scanners: They work collecting three-dimensional data using a process called “triangulation.”
• Mechanical Scanners: in this case, the master cast is read mechanically by means of a ruby ball and the three-dimensional data is acquired.

1. CAD

Data is obtained from the scanning process and, depending on the application, a data set is produced to fabricate the product. We can store the data of the construction in various data formats, but the standard is often STL files.

With CAD software, we can provide various dental restoration designs to the CAM unit.

2. CAM

A production technology which transforms the data set into the desired product through milling. We can differentiate the processing devices according to:

• Dry or Wet Milling
  • Dry Processing: Can be applied to zirconium oxide blanks with a low degree of pre-sintering.
  • Wet Processing: A spray of cool liquid protects the milling diamond or carbide cutter to avoid damage due to the heat. This process is necessary for metals and glass ceramic.

• Number of Milling Axes
• 3-axis: This milling device has degrees of movement in the three spatial directions.
• 4-axis: This device includes the tension bridge rotations as the fourth axis of movement.
• 5-axis: The fifth axis is rotating the milling spindle.

• Types of Production:

The production concepts depend on the location of the components of the CAD/CAM systems:

1. Chairside Production: We can find the components in the dental surgery.
2. Laboratory Production: The manufacturers carry out the CAD/CAM production steps.
3. Centralized Fabrication: “Satellite scanners” in the dental laboratory can connect with a production center through the internet.

Materials:

Now we can show you the materials which we can use on dental CAD/CAM devices:

1. Metal: Such as titanium, titanium alloys, and chrome cobalt alloys.
2. Resin Materials: Used for the milling of lost wax frames for casting technology and as crown and FPD (Fixed Partial Denture) frameworks for long-term provisional or for full anatomical long-term temporary prostheses.
3. Silica-based Ceramics: For the production of veneers, onlays, inlays, partial crowns, and full crowns.
4. Infiltration Ceramics: Three variations which we can use, that is Vita In-Ceram Alumina, Vita In-Ceram Zirconia, and Vita In-Ceram Spinell. They are adequate for producing crown copings and FPD frameworks.
5. Oxide High-performance Ceramics: Blocks of aluminum oxide and zirconium oxide, used to produce crowns, FPD frameworks, and even implant abutments.

                     Dr.Mohamed Adel-د.محمد عادل