A framework for custom design and fabrication of cranio-maxillofacial prostheses using investment casting

This work aims to enhance the design process and to develop a protocol for fabricating customized cranio-maxillofacial prostheses.The approach entails four tasks: Image processing, biomodelling, fabrication and finishing. The image processing comprises image segmentation and 3D reconstruction of the patient’s anatomy. The biomodelling consists in designing a custom-fit cranio-maxillofacial prosthesis. Finally, the fabrication is performed through investment casting.Thin ceramic shells are fabricated using wax models, which are previously obtained by wax injection in silicone moulds and wax printing. The wax is eliminated by flash firing and the shell is sintered for 2 hours at 1450◦C. Then, a titanium alloy is melted and casted under a controlled atmosphere using a copper cold crucible. The final step is the surface finishing using chemical milling that removes the superficial α-case layer and reduces the prostheses’ thickness. Ultimately, a 5-axis CNC machining is used to smooth the surface and to drill the holes for the attachment system.