T. SOHMURA* and J. TAKAHASHI ( Department of Dental Materials Science and Technology, Osaka University Faculty of Dentistry, Osaka, Japan )
We have studied on the CAD/CAM system to fabricate dental prostheses, and originally developed the measuring, CAD and CAM system for crown and bridge. In the present paper, improvement of CAD process for crown and bridge considering the adjustment with the antagonistic teeth is reported. Initially, the shape data of a standard crown were deformed and applied on the die data measured. Here, the shape data of antagonistic teeth obtained by measuring the bite were taken in, and the bite adjustment of applied crown with the bite data was carried out. In the previous version of the program, the interfered portions of the applied crown with bite were eliminated by trimming the data of crown. While in the present case, they were checked automatically, and the shape and height of each interfered cusp were deformed up to disappear the interference. The movement of the antagonistic teeth by occlusion was considered by checking the interference of the applied crown with the measured FGP data.
In the case of CAD for bridge, the shape of standard pontic was measured and inserted between two crowns designed on the dies. The clearances between crown and pontic was connected, and the interference with bite data was checked also, and adjusted by deforming the cusp of the applied bridge.
In the CAD for crown and bridge, by the newly developed process of deformation of each cusps of applied crown, better occlusal relation with antagonistic teeth could be established.