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S. Baumgartner, J. Stampfl:
"Additive Manufacturing of dental glass ceramics";
Talk: ViCEM - Vienna Center for Engineering in Medicine Biennial Meeting 2019, Wien; 11-14-2019 - 11-15-2019.

With additive manufacturing (AM) on the rise in industrial production, different industries are looking for a way to benefit from the advantages over conventional manufacturing methods like milling or casting. On the one hand, the layer by layer approach allows the parallel construction of different complex structures with nearly unlimited freedom of design. On the other hand, the labour-intensive tool production in no longer required, while waste material is significantly reduced. This is especially interesting for the processing of advanced ceramic materials, where often customized and single parts are inquired. Regarding ceramics, stereolithography (SLA) provides the highest surface quality and achievable precision compared to any other AM technologies, which is necessary to meet the high demands from industry regarding accuracy and reproducibility. At TU Wien, we successfully process different kinds of ceramics and glasses, like zirconia (ZrO2), alumina (Al2O3), tricalcium phosphate (TCP) and bioactive glasses by using specially developed SLA-printers based on digital light processing (DLP). The so-called slurry is photopolymerized into a green body, debinded and sintered, which leads to a shrinkage of up to 25 %. With dental industry asking for customized and aesthetic restorations, the additive manufacturing of glass ceramic materials is highly requested. Glass ceramics exhibit high thermal shock resistance and mechanical as well as aesthetic properties. Now for the first time, the glass ceramic system lithium disilicate could be processed with an AM technology, offering defect free dental restorations with outstanding mechanical properties of up to 400 MPa flexural strength and excellent translucency. Challenges as opacity and sinter distortion due to viscous flow behaviour were overcome. Veneers, crowns and even bridges, especially for the anterior tooth area can be reproducibly printed, debinded and sintered to dense, resistant glass ceramic parts.

Stereolithography, Glass ceramics