Yttria (Y₂O₃) plays a crucial role in the field of dental restoration, primarily serving as a stabilizer added to zirconia (ZrO₂) for the fabrication of dental restorations. The detailed information about yttria used in dentistry is as follows:

Stabilizing the Crystal Structure of Zirconia

Enhancing the Mechanical Properties of Zirconia

Yttria-stabilized zirconia (YSZ) possesses high flexural strength and fracture toughness. For example, the first-generation 3Y-TZP has a flexural strength of approximately 1200 MPa and a fracture toughness ranging from 9 to 10 MPa·m¹/². The reason behind its high strength lies in the fact that cracks trigger a local crystal structure transformation from the tetragonal phase to the monoclinic phase. This transformation absorbs crack energy and counteracts crack propagation, enabling the material to withstand the biomechanical loads in the oral cavity over the long term.

Improving the Aesthetic Properties of Zirconia

Exhibiting Excellent Biocompatibility

Yttria-containing zirconia demonstrates superior biological properties, including low corrosion potential, low cytotoxicity, and low bacterial adhesion. Numerous in vitro studies have shown that zirconia has no cytotoxicity to osteoblasts and fibroblasts. In vivo studies have also confirmed that yttria-containing zirconia implanted in rats exhibits no cytotoxicity, and its osseointegration effect and soft tissue attachment potential are comparable to those of titanium alloys.