The overall objective of this study is to confirm the method of determining the accuracy of Kubelka‐Munk reflectance theory (KMRT) for composite materials after undergoing aging unrelated to surface exposure. The specific aims of this study include comparisons of optical characterizations for two dental resin composite materials before and after aging in darkness. Aging of five shades of two nanohybrid dental resin composite materials was accomplished under relatively normal room conditions in a dark enclosure for over 3 years. The accuracy of KMRT was assessed and optical absorption and scattering and color and translucency characterizations were performed. The magnitudes of the error of nonlinear regression of reflectance after aging to KMRT are well within the limits of expected measurement error as applied to regression analysis. The characterizations of inherent optical scattering, inherent color, and translucency indicate that aging in darkness will have some effect for at least some shades of the materials studied. KMRT is a reliable method to predict the reflectance of dental resin aged in darkness and permits subsequent clinically relevant optical characterizations of materials aged in this manner. Although changes in optical scattering were detected due to this aging, such changes appear to have a negligible clinical effect on color and translucency.

中文翻译：

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在黑暗中老化的牙科树脂复合材料的体外光学表征

这项研究的总体目标是确定一种确定与表面暴露无关的老化后复合材料的Kubelka-Munk反射理论（KMRT）的准确性的方法。这项研究的具体目标包括在黑暗中老化前后两种牙科树脂复合材料的光学特性比较。在相对正常的室内条件下，在黑暗的密闭环境中进行了超过5年的两种纳米混合牙科树脂复合材料的老化处理。评估KMRT的准确性，并进行光吸收和散射以及颜色和半透明性表征。老化至KMRT后，反射率非线性回归的误差幅度完全在预期的测量误差范围之内（应用于回归分析）。固有的光学散射，固有的颜色和半透明性的特征表明，黑暗中的老化至少会对所研究材料的某些阴影产生影响。KMRT是预测在黑暗中老化的牙科树脂的反射率的可靠方法，并允许以这种方式对材料进行后续的临床相关光学表征。尽管由于这种老化而检测到光散射的变化，但是这种变化对颜色和半透明性的临床影响似乎可以忽略不计。KMRT是预测在黑暗中老化的牙科树脂的反射率的可靠方法，并允许以这种方式对材料进行后续的临床相关光学表征。尽管由于这种老化而检测到光散射的变化，但是这种变化对颜色和半透明性的临床影响似乎可以忽略不计。KMRT是预测在黑暗中老化的牙科树脂的反射率的可靠方法，并允许以这种方式对材料进行后续的临床相关光学表征。尽管由于这种老化而检测到光散射的变化，但是这种变化对颜色和半透明性的临床影响似乎可以忽略不计。