Della Bona Alvaro, Pecho Oscar E, Ghinea Razvan, Cardona Juan C, Pérez María M
Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Brazil.
Post-graduate Program in Dentistry, Dental School, University of Passo Fundo, Brazil; Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, s/n, 18071 Granada, Spain.
J Dent. 2015 Jun;43(6):726-34. doi: 10.1016/j.jdent.2015.02.015. Epub 2015 Mar 6.
To evaluate colour differences between (1) CAD-CAM ceramic systems considering shades A1, A2 and A3 and the corresponding nominal shade of VC (Vita Classical shade guide) and (2) shades A1-A2, A2-A3 and A1, A2 and A3 within the same ceramic system.
Samples of shades A1, A2 and A3 were fabricated (n=5) from CAD-CAM ceramic blocks (IPS e.max(®) CAD LT and HT, IPS Empress(®) CAD LT and HT, Paradigm™ C, and VITABLOCS(®) Mark II) and polished to 1.0±0.01mm in thickness. Spectral reflectance and colour coordinates were measured using a spectroradiometer inside a viewing booth using the CIE D65 illuminant and the d/0° geometry. Spectral reflectance curves were compared using VAF coefficient and were statistically analyzed using Kruskal-Wallis and the Mann-Whitney U test (α=0.05). Colour coordinates were statistically analyzed using one-way ANOVA, Tukey's test with Bonferroni correction (α=0.001). All colour differences (ΔEab(*) and ΔE00) were analyzed through comparisons with the PT - perceptibility and AT - acceptability thresholds for dental ceramics.
ΔE between ceramic systems and its corresponding shade ranged from 6.32 to 13.42 (ΔEab()) and 4.48 to 9.30 (ΔE00). ΔE between shades A1-A2, A2-A3 and A1, A2 and A3 ranged, respectively, 1.93-4.82, 1.22-5.59 and 3.63-8.84 (ΔEab()); 1.54-3.87, 1.03-3.90 and 2.95-6.51 (ΔE00).
Considering the corresponding nominal shade from VC, none of the ceramic systems showed colour differences below the AT. In addition, some ceramic systems showed colour differences below AT (shades A1-A2 and A2-A3) and below PT (shades A2-A3).
Careful adjustments should be made to the final shade of CAD-CAM ceramic restorations to reach a clinically acceptable shade match.
评估（1）考虑A1、A2和A3色阶以及相应的Vita古典比色板（VC）标称色阶的计算机辅助设计与计算机辅助制造（CAD-CAM）陶瓷系统之间的颜色差异，以及（2）同一陶瓷系统内A1 - A2、A2 - A3以及A1、A2和A3色阶之间的颜色差异。
用CAD-CAM陶瓷块（IPS e.max® CAD LT和HT、IPS Empress® CAD LT和HT、Paradigm™ C以及VITABLOCS® Mark II）制作A1、A2和A3色阶的样本（n = 5），并抛光至厚度为1.0±0.01mm。在观察箱内使用分光辐射计，采用CIE D65照明体和d/0°几何条件测量光谱反射率和颜色坐标。使用VAF系数比较光谱反射率曲线，并采用Kruskal-Wallis检验和Mann-Whitney U检验进行统计分析（α = 0.05）。颜色坐标采用单因素方差分析、经Bonferroni校正的Tukey检验进行统计分析（α = 0.001）。通过与牙科陶瓷的PT - 可察觉性阈值和AT - 可接受性阈值进行比较，分析所有颜色差异（ΔEab(*)和ΔE00）。
陶瓷系统与其相应色阶之间的ΔE范围为6.32至13.42（ΔEab()）和4.48至9.30（ΔE00）。A1 - A2、A2 - A3以及A1、A2和A3色阶之间的ΔE分别为1.93 - 4.82、1.22 - 5.59和3.63 - 8.84（ΔEab()）；1.54 - 3.87、1.03 - 3.90和2.95 - 6.51（ΔE00）。
考虑到VC的相应标称色阶，没有一个陶瓷系统的颜色差异低于可接受性阈值。此外，一些陶瓷系统的颜色差异低于可接受性阈值（A1 - A2和A2 - A3色阶）以及低于可察觉性阈值（A2 - A3色阶）。
对于CAD-CAM陶瓷修复体的最终色阶应进行仔细调整，以达到临床可接受的颜色匹配。
