[An approach to the dental CAD/CAM (Part 4). Fundamental CAD procedure for the data base]

Studies are currently underway to apply the CAD/CAM system to dentistry and to make prosthetic appliances automatically. This paper reports the basic CAD procedure by using the CAD data base in the previous (part 3) report and gives some modified teeth figures. Mathematically, with Affine transformation, extension, contraction, parallel translation, and rotation of the dental figures are done. In the transformation, the origin of the individual tooth is decided from the mean value of the data base points, and X, Y, Z coordinates are the bucco-lingal, mesio-distal, vertical directions, respectively. This basic transforming procedure reduces the time needed for the CAD procedure.