Mikhail Sarah S, Schricker Scott R, Azer Shereen S, Brantley William A, Johnston William M
The Ohio State University, College of Dentistry, Division of Restorative, Prosthetic and Primary Care Dentistry, Columbus, OH, USA.
J Dent. 2013 Sep;41(9):771-8. doi: 10.1016/j.jdent.2013.07.001. Epub 2013 Jul 12.
Optical and physical properties of dental restorative composite materials are affected by composition. Basic optical absorption and scattering properties have been derived through the use of a corrected reflectance model, but practical and important optical properties are not easily derived from these basic spectral characteristics. The purposes of this study are to derive and compare colour and translucency characteristics of two cured contemporary nanohybrid composites being marketed as universal composites, and to evaluate colour difference between each composite material and published shade guide data.
Previously derived optical scattering and absorption coefficients for five diverse shades of these composite materials were used to calculate the CIE colour parameters of L*, a* and b* at infinite thickness under various illuminants and to derive ideal translucency parameters at various thicknesses using two colour difference formulae.
Differences were found in the inherent colour parameters and in the translucency parameters between the brands for some of the shades studied. The colour differences of the inherent colours from published shade guide data were always higher than the perceptibility limit, and often higher than the acceptability limit.
Inherent colours and ideal translucency parameters may be calculated from optical coefficients for a variety of illuminants. Different inherent colour parameters of composite materials marked for the same shade indicate the influence of compositional differences between these materials.
Since patients are seen under various illuminations, the ability to assess appearance matching characteristics under diverse illuminants will help assure an optimum match for the patient.
牙科修复复合材料的光学和物理性能受其成分影响。已通过使用校正反射率模型得出基本的光吸收和散射特性，但实际且重要的光学性能并非轻易能从这些基本光谱特征中得出。本研究的目的是推导并比较两种作为通用复合材料销售的当代固化纳米混合复合材料的颜色和半透明特性，并评估每种复合材料与已发表的比色板数据之间的色差。
利用先前得出的这两种复合材料五种不同色度的光散射和吸收系数，计算在各种照明条件下无限厚度时的CIE颜色参数L*、a和b，并使用两种色差公式推导不同厚度下的理想半透明参数。
在所研究的某些色度中，发现不同品牌之间在固有颜色参数和半透明参数方面存在差异。与已发表的比色板数据相比，固有颜色的色差始终高于可察觉极限，且常常高于可接受极限。
可根据各种照明条件下的光学系数计算固有颜色和理想半透明参数。标注相同色度的复合材料具有不同的固有颜色参数，这表明这些材料之间成分差异的影响。
由于患者是在各种照明条件下被观察的，因此能够评估不同照明条件下的外观匹配特性将有助于确保为患者实现最佳匹配。
