Preparation and properties of ternary rare earth co-stabilized zirconia ceramics for dental restorations

High fracture toughness and excellent hydrothermal aging resistance are the characteristics required for dental ceramic materials, but the widely used dental ceramic currently (3Y-TZP) does not exhibit. Aiming to solve this problem, a ternary rare earth co-stable zirconia ceramic (1.5Y5.5Ce0.3La-ZrO2) was prepared by a coating method based on a co-doping strategy. The sintering process, densification evolution, mechanical properties, resistance to hydrothermal aging and biocompatibility of 1.5Y5.5Ce0.3La-ZrO2 ceramic were studied. The results show that 1200 °C is the best pre-sintering temperature, and the machinability and controllability of shrinkage can meet the needs. When the final sintering temperature is 1600 °C, it has the best performance. Compared with 3Y-TZP, the bending strength is about 8.7% higher (912.48 MPa), and the fracture toughness is about 76.6% higher (10.49 MPa m1/2). Furthermore, its resistance to hydrothermal aging is significantly enhanced, greatly extending the service life of the material. The biosafety of 1.5Y5.5Ce0.3La-ZrO2 ceramics was evaluated, and the results showed that the material had no cytotoxicity. To sum up, 1.5Y5.5Ce0.3La-ZrO2 ceramics is a promising dental biomaterial, which has a broad application prospect in oral restoration.