FAST-MED - Research project

Additive manufacturing of ceramics allows the producing of medical prostheses with complex geometries and tailored internal architectures, to allow for example enhanced bone integration.
Stereolithography (SLA) of ceramics is based on a layer-by-layer polymerization of pastes that are composed of ceramic particles and monomers. A near-UV laser polymerizes a given pattern defined by a CAD file to process the green ceramic part. Multifunctional monomers polymerization and consecutive layers curing zones superposition ensure its mechanical strength. High ceramic loading in SLA pastes and particles dimensions impact photons trajectories and thus polymerization. If paste-laser interaction is well controlled, debinding and sintering steps allow obtaining a high-density ceramic part from this polymerized printed object.
Zirconia stabilization by Cerium oxide (ex. Ce-TZP) provides good mechanical properties for biomedical applications like jaw prostheses. The main interest of Ceria-doped zirconia is its stress-induced structural transformation which leads to a transformation-induced plasticity (quite similar to the TRIP effects well known in certain metals) and a better crack propagation resistance. Ce-TZP based materials do not undergo aging when in contact with biological fluids, ensuring a perfect stability on longer timescales for implanted devices.
SLA development for Ce-TZP based composites could therefore permit to process architectured objects with complex geometries and surfaces that could be adapted to different load-bearing prostheses, for which a high resistance to crack propagation is requested.
The FAST-MED project ultimately aims at processing Ce-TZP biomedical ceramics by SLA, with different steps: understanding of structure - rheology relations in commercial and developed SLA pastes, describing and optimising paste-laser interactions, processing of complex shapes and architectures for bone replacement, mechanical and biological assessment.