Department of Dental and Biomedical Materials Science, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
Department of Dental and Biomedical Materials Science, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
Dent Mater. 2016 May;32(5):660-7. doi: 10.1016/j.dental.2016.02.004. Epub 2016 Feb 28.
This study was conducted to investigate thickness dependence of light transmittance, translucency and opalescence of a commercially available fully-sintered ceria-stabilized zirconia/alumina nanocomposite for dental all-ceramic restorations.
Three disk samples of 16 mm in diameter and thickness ranging from 0.2 to 0.6 mm with 0.1 mm increment each were cut from a fully-sintered rod-shaped Ce-TZP/alumina nanocomposite (NANOZR, Panasonic Healthcare, Japan) and polished flat by using diamond slurry. Spectral light transmittance data under the CIE standard illuminant D65 were recorded at 10nm intervals from 360 to 740 nm using a computer-controlled spectrophotometer. Average transmittance, translucency and opalescence parameters were determined as a function of sample thickness. Optical properties of a fully-sintered yttria-stabilized tetragonal zirconia polycrystals (Cercon(®) base, DeguDent GmbH, Germany) were also investigated as a reference. Two-way ANOVA was performed to determine the significant differences in various optical parameters among types of ceramic and thicknesses at α=0.05.
Results of the two-way ANOVA showed that the average transmittance, translucency and opalescence parameters of both ceramic materials were significantly influenced by the type of ceramic and thickness (p<0.001). Light transmittance of the NANOZR was significantly lower than that of the Cercon(®) base. For both ceramic materials, average transmittance of light and translucency parameter decreased with sample thickness following exponential functions. The NANOZR showed substantially higher opalescence parameters exceeding 20 CIE units when the sample thickness was nearly 0.3 mm. The prominent characteristics of high opalescence and low transmittance of light in the NANOZR was considered to be caused by its specific very fine interpenetrated intragranular microstructure and by a large difference of refractive indices of Ce-TZP and alumina components.
High opalescence and low transmittance of light of the ceria-stabilized zirconia/alumina nanocomposite (NANOZR) are attractive properties for use as a substructure in fabricating porcelain-veneering-type esthetic all-ceramic restorations.
本研究旨在探讨一种商用全烧结氧化铈稳定氧化锆/氧化铝纳米复合材料的透光率、半透明度和乳光性随厚度的变化。
从全烧结氧化铈稳定氧化锆/氧化铝纳米复合材料（NANOZR，日本松下医疗）的棒状样品上切下三个直径为 16mm、厚度分别为 0.2mm、0.3mm、0.4mm、0.5mm、0.6mm，厚度间隔为 0.1mm 的圆盘试件，并用金刚石浆抛光成平面。使用计算机控制分光光度计在 CIE 标准照明体 D65 下以 10nm 的间隔记录从 360nm 到 740nm 的光谱光透射率数据。作为厚度的函数，确定平均透光率、半透明度和乳光参数。还研究了全烧结氧化钇稳定四方氧化锆多晶（Cercon®基底，德国 DeguDent GmbH）的光学性能作为参考。采用双向方差分析（Two-way ANOVA）在α=0.05 水平上确定两种陶瓷材料的各种光学参数在不同类型陶瓷和厚度之间的显著差异。
双向方差分析的结果表明，两种陶瓷材料的平均透光率、半透明度和乳光参数均受陶瓷材料类型和厚度的显著影响（p<0.001）。NANOZR 的透光率明显低于 Cercon®基底。对于两种陶瓷材料，随着样品厚度的增加，光的平均透射率和半透明度参数均呈指数下降。当样品厚度接近 0.3mm 时，NANOZR 表现出显著更高的乳光参数超过 20CIE 单位。NANOZR 表现出高乳光和低透光的显著特征，这被认为是由于其特定的非常细的相互贯穿的颗粒内微观结构以及氧化铈稳定氧化锆和氧化铝成分之间折射率的巨大差异所致。
氧化铈稳定氧化锆/氧化铝纳米复合材料（NANOZR）的高乳光和低透光率是作为制造烤瓷贴面式全瓷修复体的底层结构的有吸引力的特性。
