In this work a 3mol% yttria stabilized zirconia ceramic (LithaCon 3Y 210), which is suitable for processing with vat-based photopolymerization, was characterized based on the standards DIN EN ISO 13356 and DIN EN ISO 6872. The aim of the study was to determine, whether the material can be used in dental applications and surgical implants. In addition, a demonstrator should show the realization of an additively manufactured implant for the application as surgical treatment of herniated discs. All specimens were fabricated by the LCM (Lithography based Ceramic Manufacturing) process using a CeraFab 7500 system. Characterization was performed by determining flexural strength, Young’s modulus, hardness, fracture toughness, coefficient of linear thermal expansion and chemical solubility. The microstructure was characterized by quantitative ceramography. Furthermore, the flexural strength of specimens of the material variant LithaCon 3Y 230, which is based on a different slurry, as well as the influence of different specimen orientations during the printing process on the Young's modulus, thermal expansion and fracture toughness were investigated.
The monoclinic phase content, Young's modulus, hardness, grain size and chemical solubility meet the requirements of the standards. The coefficient of linear thermal expansion is in the range of values of conventionally manufactured samples. No influence of the AM printing direction on Young's modulus and thermal expansion could be detected, indicating that a homogeneous material state could be achieved in the LCM process. The determined flexural strengths are slightly below the minimum requirements of the standard with a slightly high scatter of values (low Weibull modulus). This may be due to the fact that samples printed in Z-direction were tested with an untreated surface (as-fired). For fracture toughness, a typical value for 3Y-TZP ceramics was measured using samples with sharp pre-cracks. Based on the values obtained for flexural strength and fracture toughness, LithaCon 3Y 210 can be classified as Class 4 of the Standard for Dentistry - Ceramic Materials.
The work was carried out within the project I AM RRI - Webs of Innovation Value Chains of Additive Manufacturing (AM) under Consideration of RRI (EU Horizon 2020, grant no. 788361) in cooperation with the company Lithoz GmbH, Vienna.