Digitized occlusal reconstruction for dental prostheses

The aim of this study was to explore a method for automatically reconstructing the occlusal surface by CAD technology. A 3D graphic database of standard tooth crown (STC) was established from physical models. Referring to the contact rule, the occlusal surface of STC was partitioned into several functional regions, and the regions related with occlusal adjustment were further defined as some sets of discrete points. Additionally, geometrical marks were added to the database to embody dimensional contours and orientation of STC. Then an adaptive redesign methodology was developed to form occlusal surface: firstly, a STC similar to patient's anatomical characteristics was scaled and registered to the abutment teeth; secondly, the distances between the point sets and the antagonist were calculated to quantify the occluding relation; finally, the occlusal surface was reconstructed by local deformation. The program provided a novel method to automatically adjust the size and location of the restoration, avoid interpenetrations and create necessary contacts. The final occlusal surface fulfills the esthetic and morphologic criteria in clinical dentistry and meets the physiologic demands of occlusal and proximal contacts.