PDF(Pubmed)
Abstract：
BACKGROUND: Effects of ceramic translucency, layer thickness, and substrate colour on the shade of lithium disilicate glass-ceramic restorations proved to be significant in several studies, however, quantitative, numerical results on the relationship between the colour difference and these parameters are still lacking. The purpose of this in vitro study was to quantitatively determine how the colour reproduction ability of a lithium disilicate glass-ceramic is affected by its translucency, layer thickness, and substrate colour.
METHODS: Ceramic samples were prepared from A2 shade IPS e.max CAD blocks with high and low translucencies (HT and LT) in a thickness range of 0.5-2.5 mm (+/- 0.05 mm). Layered samples were acquired utilizing composite substrates in 9 shades; transparent try-in paste was used. The spectral reflectance of the specimens was assessed under D65 standard illumination with a Konica Minolta CM-3720d spectrophotometer. The CIEDE2000 colour difference (ΔE00) between two samples was analysed using perceptibility and acceptability thresholds set at 50:50%. Statistical analysis involved linear regression analysis and the Kruskal-Wallis test.
RESULTS: An increase in the thickness of 0.5 mm reduced the ΔE00 of the HT samples to 72.8%, and that of the T samples to 71.1% (p < 0.0001). 7 substrates with HT and LT specimens had significantly different results from the mean (p < 0.05). A thickness of 0.5 mm is not sufficient to achieve an acceptable result at any level of translucency, while the low translucency ceramic at a thickness of 1.5 mm gave acceptable results, except for severely discoloured substrates (ND8 and ND9).
CONCLUSIONS: The colour reproduction ability of lithium disilicate glass-ceramics is significantly affected by their translucency, layer thickness, and 7 substrates out of 9 substrates examined.
METHODS: Ceramic samples were prepared from A2 shade IPS e.max CAD blocks with high and low translucencies (HT and LT) in a thickness range of 0.5-2.5 mm (+/- 0.05 mm). Layered samples were acquired utilizing composite substrates in 9 shades; transparent try-in paste was used. The spectral reflectance of the specimens was assessed under D65 standard illumination with a Konica Minolta CM-3720d spectrophotometer. The CIEDE2000 colour difference (ΔE00) between two samples was analysed using perceptibility and acceptability thresholds set at 50:50%. Statistical analysis involved linear regression analysis and the Kruskal-Wallis test.
RESULTS: An increase in the thickness of 0.5 mm reduced the ΔE00 of the HT samples to 72.8%, and that of the T samples to 71.1% (p < 0.0001). 7 substrates with HT and LT specimens had significantly different results from the mean (p < 0.05). A thickness of 0.5 mm is not sufficient to achieve an acceptable result at any level of translucency, while the low translucency ceramic at a thickness of 1.5 mm gave acceptable results, except for severely discoloured substrates (ND8 and ND9).
CONCLUSIONS: The colour reproduction ability of lithium disilicate glass-ceramics is significantly affected by their translucency, layer thickness, and 7 substrates out of 9 substrates examined.
摘要：
背景：陶瓷半透明的影响，层厚度,在一些研究中，二硅酸锂玻璃陶瓷修复体的阴影和基底颜色被证明是重要的，然而,定量,关于色差与这些参数之间关系的数值结果仍然缺乏。这项体外研究的目的是定量确定二硅酸锂玻璃陶瓷的颜色再现能力如何受到其半透明性的影响。层厚度,和基材颜色。
方法:陶瓷样品由具有高和低半透明性(HT和LT)的A2色调IPSE.maxCAD块在0.5-2.5mm(+/-0.05mm)的厚度范围内制备。利用9种色调的复合基材获得分层样品;使用透明试吃膏。在D65标准照明下用柯尼卡美能达CM-3720d分光光度计评估样品的光谱反射率。使用设定为50：50％的可感知性和可接受性阈值分析了两个样品之间的TheCIEDE2000色差（ΔE00）。统计分析包括线性回归分析和Kruskal-Wallis检验。
结果：厚度增加0.5mm时，HT样品的ΔE00降低到72.8％，T样品的比例为71.1%(p<0.0001)。具有HT和LT样品的7种底物具有与平均值显著不同的结果(p<0.05)。0.5mm的厚度不足以在任何半透明水平下实现可接受的结果，而厚度为1.5毫米的低半透明陶瓷给出了可接受的结果，除了严重变色的底物（ND8和ND9）。
结论：二硅酸锂微晶玻璃的颜色再现能力受半透明性的显著影响，层厚度,和检查的9个衬底中的7个衬底。
方法:陶瓷样品由具有高和低半透明性(HT和LT)的A2色调IPSE.maxCAD块在0.5-2.5mm(+/-0.05mm)的厚度范围内制备。利用9种色调的复合基材获得分层样品;使用透明试吃膏。在D65标准照明下用柯尼卡美能达CM-3720d分光光度计评估样品的光谱反射率。使用设定为50：50％的可感知性和可接受性阈值分析了两个样品之间的TheCIEDE2000色差（ΔE00）。统计分析包括线性回归分析和Kruskal-Wallis检验。
结果：厚度增加0.5mm时，HT样品的ΔE00降低到72.8％，T样品的比例为71.1%(p<0.0001)。具有HT和LT样品的7种底物具有与平均值显著不同的结果(p<0.05)。0.5mm的厚度不足以在任何半透明水平下实现可接受的结果，而厚度为1.5毫米的低半透明陶瓷给出了可接受的结果，除了严重变色的底物（ND8和ND9）。
结论：二硅酸锂微晶玻璃的颜色再现能力受半透明性的显著影响，层厚度,和检查的9个衬底中的7个衬底。
