Lee Yong-Keun
Department of Dental Biomaterials Science, Dental Research Institute, College of Dentistry, Seoul National University, Seoul, Republic of Korea.
Dent Mater. 2007 Jan;23(1):124-31. doi: 10.1016/j.dental.2006.01.007. Epub 2006 Feb 17.
Optical scattering has been studied because of its important effects on the color and translucency of a material. The objective of this study was to determine the influence of the scattering and absorption characteristics including translucency and opalescence on the CIE color coordinates (L(), a(), and b(*)) of resin composites.
Color and spectral distribution of seven resin composites (14 shades, 1mm thick) were measured in the reflectance and the transmittance modes. Optical constants including scattering coefficient (S), absorption coefficient (K) and light reflectivity (RI) were calculated from the spectral reflectance data using Kubelka's equations. The opalescence parameter (OP) was calculated as the difference in yellow-blue (Deltab()) and red-green (Deltaa()) coordinates between the reflected and transmitted colors. The translucency parameter (TP) was calculated for the translucency evaluation. Simple correlation among each of CIE L(), a() and b(*) values measured using varied protocols with optical parameters (S, K, RI, OP and TP) was determined, and multiple regression analysis was used to determine the significantly influencing variables on the color coordinates (p<0.05).
CIE L(), a(), and b() values were influenced by S, K, RI, TP and OP values. The CIE L() value without backing and that in the transmission mode were highly correlated with S. OP and TP values also influenced CIE L() value. The CIE b() value was correlated with the OP value when different composites with the same shade designation were compared.
Since the scattering and absorption characteristics influence the color of resin composites, the size and volume fraction of fillers should be controlled for the best color reproduction, considering the refractive indices of filler and resin matrix.
由于光散射对材料的颜色和半透明性有重要影响，因此对其进行了研究。本研究的目的是确定散射和吸收特性（包括半透明性和乳光现象）对树脂复合材料的CIE颜色坐标（L(), a(), 和b(*)）的影响。
在反射和透射模式下测量了七种树脂复合材料（14种色号，1毫米厚）的颜色和光谱分布。使用库贝尔卡方程从光谱反射数据计算出包括散射系数（S）、吸收系数（K）和光反射率（RI）在内的光学常数。乳光参数（OP）计算为反射色和透射色之间黄蓝（Deltab()）和红绿（Deltaa()）坐标的差值。计算半透明参数（TP）用于半透明性评估。确定了使用不同方案测量的CIE L(), a()和b(*)值与光学参数（S、K、RI、OP和TP）之间的简单相关性，并使用多元回归分析确定对颜色坐标有显著影响的变量（p<0.05）。
CIE L(), a(), 和b()值受S、K、RI、TP和OP值的影响。无背衬时的CIE L()值和透射模式下的CIE L()值与S高度相关。OP和TP值也影响CIE L()值。当比较相同色号的不同复合材料时，CIE b(*)值与OP值相关。
由于散射和吸收特性会影响树脂复合材料的颜色，因此在考虑填料和树脂基体的折射率时，应控制填料的尺寸和体积分数以实现最佳的颜色再现。
