氧化钇添加量对牙科氧化锆陶瓷光学性能的影响OA

Objective This study aims to investigate the effect of yttria doping content on the microstructural changes and optical properties of zirconia. Methods Zirconia materials from the same brand,with yttria additions of 3 mol％(3Y),4 mol％ (4Y),and 5 mol％ (5Y),were employed. Presintered discs were prepared,and sample specifications were designed,cut,and densified accordingly. For microstructural characterization,ceramic samples were sintered into circular discs with a diameter of 9 mm and a thickness of 2 mm. For optical performance characterization,ceramic samples were sintered into square plates measuring 6 mm× 8 mm,with thicknesses ranging from 0.5-1.0 mm in equal intervals. A total of 6 groups (n=5) were prepared. Surface morphology was examined using scanning electron microscopy,and the crystal phase proportion was refined via X-ray diffraction. The refractive index was measured with an ellipsometer,and transmittance and the contrast ratio (CR) were evaluated using a spectrophotometer. Results Increasing the yt-tria doping level resulted in enlarged crystal diameters.Among the groups,4Y exhibited the largest tetragonal phase proportion (59.49％),and 5Y had the smallest (19.46％). The refractive index decreased with increased yttria doping. Transmittance was substantially influenced by wavelength and material thickness,with long wavelengths (705 nm) achieving the highest transmittance and short wavelengths(435 nm) having the lowest for all materials. The transmittance values of the 3Y and 4Y groups were below 1％. The trans-mittance of the 5Y group exceeded 10％ at long wavelengths (705 nm) and was below 1％ at short wavelengths (435 nm).The CR values were minimally affected by thickness. The 3Y and 4Y groups had average CR values of 0.8±0.1,and statis-tical differences were observed only between select groups. The 5Y group had an average CR value of 0.4±0.2,which was statistically significantly different from those of the other groups. Conclusion Low yttria doping levels promoted the growth of tetragonal-phase crystals,and high yttria levels significantly enhanced the formation of cubic-phase crystals. A doping level of 5 mol％ yttria is necessary to effectively improve the translucency of zirconia.