Numerical simulation of the casting process of titanium tooth crowns and bridges

The objectives of this paper were to simulate the casting process of titani um tooth crowns and bridges; to predict and control porosity defect. A cast ing simulation software, MAGMASOFT, was used. The geometry of the crowns wi th fine details of the occlusal surface were digitized by means of laser me asuring technique, then converted and read in the simulation software. Both mold filling and solidification were simulated, the shrinkage porosity was predicted by a "feeding criterion", and the gas pore sensitivity was studi ed based on the mold filling and solidification simulations. Two types of d ental prostheses (a single-crown casting and a three-unit-bridge) with vari ous sprue designs were numerically "poured", and only one optimal design fo r each prosthesis was recommended for real casting trial. With the numerica lly optimized design, real titanium dental prostheses (five replicas for ea ch) were made on a centrifugal casting machine. All the castings endured ra diographic examination, and no porosity was detected in the cast prostheses . It indicates that the numerical simulation is an efficient tool for denta l casting design and porosity control. (C) 2001 Kluwer Academic Publishers.