COMPUTER-ASSISTED SYSTEM TO AUTOMATE PRODUCTION OF POSTERIOR DENTAL RESTORATIONS.

The feasibility of a system which is capable of automating production of posterior dental restorations has been investigated. Data acquisition can be accomplished in a clinical setting using standard equipment to obtain stereoscopic views of the prepared tooth, adjacent and opposing teeth, and the jaw in motion. Data from the patient is digitized with a high resolution digitizer. Stereophotogrammetric reconstruction and kinematic analysis establish the three-dimensional envelope in which the restoration must function. Ideal tooth profiles have been digitized for each of the fourteen unique teeth. Each tooth profile is represented by B-spline or Bezier curves and surfaces. Utilizing local influence properties of these curves and surfaces, the ideal profile can be modified to provide proper function and fill the available space, yielding a morphologically correct restoration which meets the unique design requirements for a specific patient. Spline curves and surfaces also ensure that the surfaces are well behaved, without discontinuities. This property facilitates generation of tool paths for numerically controlled machining.