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.
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。