Amer Rafat S, Chandrasekaran Indumathi, Johnston William M
Assistant Professor, Division of General Practice and Materials Science, The Ohio State University, Columbus, Ohio.
Assistant Professor, Division of General Practice and Materials Science, The Ohio State University, Columbus, Ohio.
J Prosthet Dent. 2016 Nov;116(5):770-776. doi: 10.1016/j.prosdent.2016.03.016. Epub 2016 Jun 14.
Dental clinicians face challenges when selecting the proper gingiva-colored composite resin.
The purpose of this study was to evaluate the coverage error (CE) of a gingiva-colored dental composite resin shade guide with regard to the optical characteristics of the attached gingiva of a selected population under 2 different illuminants: Commission Internationale de l'Eclairage (CIE) illuminants A and D65.
The spectral reflectance (SR) values of 12 shade tabs of a gingiva-colored composite resin (Amaris gingiva) were measured at 3 different locations without a backing by using a spectroradiometer and an external light source at wavelengths of 380 to 780 nm at 2-nm intervals. All SR measurements were made using 0-degree observer and 45-degree illumination, with target size 1.1 mm in diameter. The attached gingiva (AG) of 120 participants was measured with the same protocol. CIELab values were calculated from the spectral reflectance values. CEs of the attached gingiva for each of the 120 participants for each of the shade tabs and the 2 illuminants and their combination were determined and averaged. The CIEDE2000 color differences were analyzed by a repeated measures ANOVA (using the maximum likelihood estimation method and the Satterthwaite degrees of freedom method) (α=.001).
The CIEDE2000 color difference for each person's gingiva to the closest match in color to the shade guide was determined separately for CIE illuminants A and D65. CE was calculated as the averages of these color differences and was found to be 4.0 for CIE illuminant D65 and 5.8 for CIE illuminant A.
The tested gingiva-colored shade guide had different CEs under illuminant D65 than under illuminant A and exhibited metamerism. ΔE for both illuminants was greater than the clinically acceptable range reported in the literature.
牙科临床医生在选择合适的牙龈色复合树脂时面临挑战。
本研究的目的是评估一种牙龈色牙科复合树脂比色板在两种不同光源（国际照明委员会（CIE）光源A和D65）下，针对特定人群附着龈的光学特性的覆盖误差（CE）。
使用分光辐射计和外部光源，在无背衬的情况下，于380至780nm波长处以2nm间隔，在3个不同位置测量一种牙龈色复合树脂（Amaris牙龈色）的12个比色片的光谱反射率（SR）值。所有SR测量均使用0度观察者视角和45度照明，目标尺寸为直径1.1mm。按照相同方案测量120名参与者的附着龈（AG）。从光谱反射率值计算CIELab值。确定并计算120名参与者中每个人对于每个比色片以及两种光源及其组合的附着龈的CE，并求平均值。通过重复测量方差分析（使用最大似然估计法和萨特思韦特自由度法）（α = 0.001）分析CIEDE2000颜色差异。
分别针对CIE光源A和D65确定每个人牙龈与比色板最接近颜色匹配的CIEDE2000颜色差异。CE计算为这些颜色差异的平均值，发现CIE光源D65下为4.0，CIE光源A下为5.8。
所测试的牙龈色比色板在光源D65下与在光源A下具有不同的CE，并表现出同色异谱现象。两种光源的ΔE均大于文献报道的临床可接受范围。
