A new method for generating ceramic restorations: a CAD-CAM system

The CAD-CAM CEREC system is a small, complex unit developed for electronically designing and milling ceramic restorations. The system makes it possible to generate a restoration without taking impressions, developing temporary prostheses, and without laboratory assistance. The entire restorative procedure is performed in one appointment. Basic features include the following: the cavity preparation is scanned stereo-photogrammetrically, using a three-dimensional miniature video camera; the small microprocessor unit stores the three-dimensional pattern depicted on the screen; the video display serves as a format for the necessary manual construction via an electrical signal; the microprocessor develops the final three-dimensional restoration from the two-dimensional construction; the processing unit automatically deletes data beyond the margins of the preparation; the electronic information is transferred numerically to the miniature three-axis milling device; driven by a water turbine unit, the milling device generates a precision-fitting restoration from a standard ceramic block; the entire process of electronic designing and subsequent milling of a ceramic restoration requires approximately 10 to 15 minutes.