Hu Xingxue, Johnston William M
Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, OH 43210, USA.
Dent Mater. 2009 Nov;25(11):1468-73. doi: 10.1016/j.dental.2009.07.004. Epub 2009 Aug 20.
The purpose of this study is to determine a regression model which performs accurately for predicting Kubelka-Munk (K-M) absorption (K) and scattering (S) coefficients of pigment mixtures in maxillofacial elastomer (MFE).
Specimens at varying thicknesses of 19 shades of skin-colored MFE were made incorporating tan, red, yellow and black pigments. Using a non-contact 45 degrees/0 degrees spectral reflectance system, reflectance values were obtained and fit by non-linear regression to corrected K-M theory to determine observed K and S values. Predicted values were calculated using: first order linear regression model (M(1)), second order square-factor model (M(2S)), second order interaction-factor model (M(2I)) and complete second order model (M(2C)). Errors between observed and predicted values for each model at each wavelength studied are evaluated. Differences in color and the Translucency Parameter (TP) at a thickness of 1.5 mm based on CIE2000 color difference formula between observed and predicted values were also analyzed using repeated-measures ANOVA (alpha=0.05).
M(2C) shows less absolute differences in color and TP (1.5 mm) than those for the M(1) and M(2S) models (P<0.05).
Within limitations of this study, the complete second order regression model performs accurately in concentration additivity of pigmented maxillofacial elastomer mixture. This regression model is recommended as a viable alternative in the application of colorant formulation based on corrected K-M model for improving appearance match of pigmented maxillofacial prosthesis to human skin.
本研究旨在确定一种回归模型，该模型能准确预测颌面弹性体（MFE）中色素混合物的库贝尔卡-蒙克（K-M）吸收系数（K）和散射系数（S）。
制作了包含棕色、红色、黄色和黑色色素的19种肤色MFE不同厚度的样本。使用非接触式45度/0度光谱反射系统获取反射率值，并通过非线性回归拟合校正后的K-M理论，以确定观测到的K和S值。使用以下模型计算预测值：一阶线性回归模型（M(1)）、二阶平方因子模型（M(2S)）、二阶交互因子模型（M(2I)）和完全二阶模型（M(2C)）。评估了每个研究波长下每个模型观测值与预测值之间的误差。还使用重复测量方差分析（α = 0.05）分析了基于CIE2000色差公式在1.5毫米厚度下观测值与预测值之间的颜色差异和透明度参数（TP）。
M(2C)在颜色和TP（1.5毫米）方面的绝对差异比M(1)和M(2S)模型小（P<0.05）。
在本研究的局限性内，完全二阶回归模型在色素颌面弹性体混合物的浓度加和性方面表现准确。该回归模型被推荐作为基于校正后的K-M模型应用于着色剂配方的可行替代方案，以改善色素颌面假体与人体皮肤的外观匹配。
