CAD/CAM software in dental technology
CAD programmes for use in dental technology receive scan data directly from the mouth ("optical impression-taking") or indirectly by scanning impressions, bite registrations or models produced using conventional methods. Scanning can be performed using laser scanners, stripe-light scanners, mechanical scanning or other techniques. In addition, libraries are often available with datasets of prefabricated industrially fabricated components such as implants/platforms, abutments or connectors on the one hand and on the other hand templates of anatomically contoured copings, occlusal surfaces, crowns, bridge pontics etc.
CAD programmes have an important key function in the dental technology production chain. They enable imaging, linking and processing of the recorded electronic data. The user can plan and optimise the required restoration virtually taking into account the various parameters (such as material thickness, anatomical design, proximal contacts, antagonistic contacts in static and dynamic occlusion [in virtual articulators], aesthetics, coordination with other components).
Once computer-aided design (CAD) is complete, the design is transferred to and the restoration fabricated using computer-aided manufacturing (CAM). This can take place immediately afterwards and in the vicinity or at a later time and in a different location.
The same CAD and/or CAM programme can be integrated in the product of various third-party suppliers as "OEM" software.
In principle, any dental restoration can now be designed up to 100% using CAD/CAM software and fabricated using a wide range of materials, whether an inlay, CrCo framework, customised abutment, four-unit bridge, temporary crown, telescope crown tertiary structure, surgical stent or bite-raising appliance.
Essential requirements of CAD/CAM programmes used in dental technology are import and export compatibility (interfaces) with conventional data formats (in this case mainly STL format in which three-dimensional surfaces are broken down into minute, geometrical easily describable triangles). "Open" data formats can be used on any production machines (e.g. milling units or machines for generative production) for material processing. "Closed" systems in contrast provide "confidential" (i.e. company-specific, proprietary) data formats, which can only be further processed on certain, company or licensed machines.
As exceptionally high precision is required - the accuracy of dental scanners today is in the range of 5 µm to 30 µm, the accuracy required of the final fit allows a maximum error tolerance of 50 µm – suitable CAD/CAM programmes must be able to handle the extremely large datasets involved, which provide the respective computer and manufacturing system with a high data processing capacity and speed.