摘要：
目的 研究牙科领域中透射率(T)、透射系数(TP)、对比系数(CR)3种常用半透性测量指标的相互关系.方法制作Vita体瓷和釉瓷试件各6个,起始厚度为1.2 mm,逐渐打磨至1.0、0.8、0.6、0.4、0.2 mm,用PR-650型光谱扫描色度仪分别测量每个厚度下的T值、黑白背景前的颜色参数、黑白背景前的反射率,比较3种半透性测量指标T、TP、CR的关系.结果T与厚度之间呈指数关系,随着厚度的减小T值明显升高;TP值随试件厚度减小而升高,接近于直线关系;CR值随试件厚度减小而降低,接近于直线关系.不同厚度试件的T、TP、CR,除釉质瓷1.2 mm组与1.0 mm组的T值无统计学差异外,其余各组结果之间均有统计学差异.3项指标的变异系数(CV)无统计学差异.TP与T、CR与T之间均为指数关系,拟合优度分别为0.951和0.939,具有统计学意义(P<0.05).结论在本实验条件下,T、TP、CR这3种半透性的测量指标具有相同的离散度,T与TP、T与CR均为指数关系,TP和CR的测量结果不能准确地反映不同材料之间半透性差异的大小.%Objective This study aims to compare the three commonly used translucency parameters in prosthodontics: transmittance (T), contrast ratio (CR), and translucency parameter (TP).Methods Six platelet specimens were composed of Vita enamel and dental porcelain. The initial thickness was 1.2 mm. The specimens were gradually ground to 1.0, 0.8, 0.6, 0.4, and 0.2 mm. T, color parameters, and reflection were measured by a spectrocolorimeter for each corresponding thickness. T, CR and TP were calculated and compared.Results TP increased, whereas CR decreased, with decreasing thickness. Moreover, T increased with decreasing thickness, and exponential relationships were found. Two-way ANOVA showed statistical signi-ficance between T and thickness, except between T and the 1.2 mm and 1.0 mm enamel porcelain groups. No difference was found among the coefficient variations (CV) of T, CR and TP. Curve fitting indicated the existence of exponential relationships between T and CR and between T and TP. The values for goodness of fit with statistical significance were 0.951 and 0.939, respectively (P<0.05).Conclusion Under the experimental conditions, T, TP and CR achieved the same CV. T and TP, as well as T and CR, were found with exponential relationships. The value of CR and TP could not represent the translucency precisely, especially when comparing the changing ratios.
