Al Ben Ali Abdulaziz, Kang Kiho, Finkelman Matthew D, Zandparsa Roya, Hirayama Hiroshi
Department of Prosthodontics and Operative Dentistry, Tufts University School of Dental Medicine, Boston, MA.
J Prosthodont. 2014 Apr;23(3):213-20. doi: 10.1111/jopr.12080. Epub 2013 Jul 26.
The purpose of this study was to compare the effect of variations in translucency and background on color differences (ΔE) for different shades of computer-aided design and computer-aided manufacturing (CAD/CAM) lithium disilicate glass ceramics.
A pilot study suggested n = 10 as an appropriate sample size for the number of lithium disilicate glass ceramic cylinders per group. High-transparency (HT) and low-transparency (LT) cylinders (diameter, 12 mm; length, 13 mm) were fabricated in three ceramic shades (BL1, A2, C3) using CAD/CAM technology and were cut into specimen disks (thickness, 1.2 mm; diameter, 12 mm) for placement on Natural Die (ND1 and ND4) backgrounds. Four combinations of translucency and background color were evaluated in terms of color differences for the three ceramic shades: group 1 (HT ND1, reference), group 2 (HT ND4), group 3 (LT ND1), and group 4 (LT ND4). A spectrophotometer was used to measure the color differences. Nonparametric tests (Kruskal-Wallis tests) were used to evaluate the color differences among the tested groups, and Mann-Whitney U tests with Bonferroni correction were used as post hoc tests. Furthermore, for each ceramic shade, the HT groups were compared to the LT groups using the Mann-Whitney U test.
Significant differences were present among the tested groups of the same ceramic shade (p < 0.001). The highest ΔE values were observed in the HT ND4 group for BL1, while the lowest ΔE values were found in the LT ND1 group for both A2 and C3. Further, the HT groups and the groups with a darker background (ND4) showed increased ΔE values compared with the other groups (p < 0.001).
Within the limitations of this study, the results suggested that the translucency and background color significantly influenced the lithium disilicate glass ceramic color among the BL1, A2, and C3 ceramic shades. Changing the underlying color from a lighter background to a darker background resulted in increased color differences.
本研究旨在比较不同透明度和背景对不同色度的计算机辅助设计与计算机辅助制造（CAD/CAM）二硅酸锂玻璃陶瓷颜色差异（ΔE）的影响。
一项预试验表明，每组二硅酸锂玻璃陶瓷圆柱体的合适样本量为n = 10。使用CAD/CAM技术制作了三种陶瓷色度（BL1、A2、C3）的高透明度（HT）和低透明度（LT）圆柱体（直径12 mm；长度13 mm），并将其切割成试样盘（厚度1.2 mm；直径12 mm），放置在自然色模具（ND1和ND4）背景上。针对三种陶瓷色度，评估了透明度和背景颜色的四种组合的颜色差异：第1组（HT ND1，参考组）、第2组（HT ND4）、第3组（LT ND1）和第4组（LT ND4）。使用分光光度计测量颜色差异。采用非参数检验（Kruskal-Wallis检验）评估测试组之间的颜色差异，并使用经Bonferroni校正的Mann-Whitney U检验作为事后检验。此外，对于每种陶瓷色度，使用Mann-Whitney U检验比较HT组和LT组。
相同陶瓷色度的测试组之间存在显著差异（p < 0.001）。BL1的HT ND4组观察到最高的ΔE值，而A2和C3的LT ND1组均发现最低的ΔE值。此外，与其他组相比，HT组和背景较深（ND4）的组显示出更高的ΔE值（p < 0.001）。
在本研究的局限性范围内，结果表明透明度和背景颜色对BL1、A2和C3陶瓷色度的二硅酸锂玻璃陶瓷颜色有显著影响。将底色从较浅背景改为较深背景会导致颜色差异增加。
