Characterization of three commercial Y-TZP ceramics produced for their High-Translucency, High-Strength and High-Surface Area

Developing yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) with high strength and translucency could significantly widen the clinical indications of monolithic zirconia restorations. This study investigates the mechanical and optical properties of three Y-TZP ceramics: High-Translucency, High-Strength and High-Surface Area. The four-point bending strengths (mean±standard error) for the three Y-TZP ceramics (n=10) were 990±39, 1416±33 and 1076±32 MPa for High-Translucency, High-Strength and High-Surface Area, respectively. The fracture toughness values (mean±standard error) for the three zirconias (n=10) were 3.24±0.10, 3.63±0.12 and 3.21±0.14 MPa m1/2 for High-Translucency, High-Strength and High-Surface Area, respectively. Both strength and toughness values of High-Strength zirconia were significantly higher than High-Surface Area and High-Translucency zirconias. Translucency parameter values of High-Translucency zirconia were considerably higher than High-Strength and High-Surface Area zirconias. However, all three zirconias became essentially opaque when their thickness reached 1 mm or greater. Our findings suggest that there exists a delicate balance between mechanical and optical properties of the current commercial Y-TZP ceramics.