An additively manufactured Al2O3 whisker/3Y-TZP ceramic with high mechanical and low-temperature aging properties fabricated by stereolithography technology for dental applications

The 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) ceramic has potential dental restoration applications due to its sufficient mechanical strength, high esthetic potential, and biocompatibility. Nevertheless, the conventional clinical processing of 3Y-TZP ceramic has a significant amount of material waste, high tool wear, and the possible formation of microcracks. In this study, alumina whisker (Al 2 O 3 w)-reinforced 3Y-TZP ceramic composites were prepared using the stereolithography technology followed by sintering for dental crown applications. This study aimed to address current manufacturing defects in dental ceramics by fabricating tough, strengthened zirconia ceramics using 3D printing technology. The results indicate that the grain size and distribution homogeneity of the ZrO 2 phase, mechanical properties, and hardness of the 3Y-TZP/Al 2 O 3 w specimens were better than those of the 3Y-TZP specimen, while the relative density showed a decrease with an increase in Al 2 O 3 w contents. The 3Y-TZP/7.5 % Al 2 O 3 w composite showed the best mechanical performance with a flexural strength of ∼863.0 MPa, a Vickers hardness of ∼13.2 GPa, and a fracture toughness of ∼6.6 MPa m 1/2 , which is about 13.1 %, 9.7 % and 25.1 % higher than those of 3Y-TZP specimens. The low-temperature degradation testing revealed that the addition of the reinforcement Al 2 O 3 w improved the anti-aging properties of 3Y-TZP specimens. Further, the 3Y-TZP/Al 2 O 3 w ceramic composite samples showed good cytocompatibility with a cell viability of higher than 90 % toward L929 cells and prototyping properties.