Lee Yong-Keun, Lim Bum-Soon, Rhee Sang-Hoon, Yang Hyeong-Cheol, Powers John M
Department of Dental Biomaterials Science, Dental Research Institute, College of Dentistry, Seoul National University, Seoul, Korea.
Oper Dent. 2005 Jul-Aug;30(4):436-42.
This study determined the differences in values and changes of color and translucency of eight brands of A2 shade resin composites after curing, polishing and thermocycling (TC). The color of specimens 10-mm in diameter and 2-mm thick was measured on a reflection spectrophotometer with SCE geometry under D65 illumination over a white and black background. Measurements were obtained before curing, after curing, after polishing and after TC. The color change (deltaEab), translucency parameter (TP) and contrast ratio (CR) were then compared. The range of deltaEab after curing was 3.8 to 10.2 (average deltaEab for the eight composites = 6.4), which was deemed perceptible to the observer. Polishing caused deltaEab of 1.9 to 4.5, which was perceptible in five of the eight composites. After 2,000 TC, deltaE*ab was 0.4 to 1.3. TP values tended to increase after curing and decrease after TC (range before curing was 7.1 to 17.2). Changes in TP values after curing were statistically significant in all composites (p<0.05). Changes in CR values were similar to the translucency changes in TP. Though the composite shades were all designated as A2, color coordinates, TP and CR values, changes in color and translucency after curing, polishing and thermocycling varied by brand.
本研究测定了8个品牌A2色号树脂复合材料在固化、抛光和热循环（TC）后颜色和透明度的值及变化差异。在D65照明条件下，于白色和黑色背景上，使用SCE几何结构的反射分光光度计测量直径10毫米、厚2毫米的试样颜色。在固化前、固化后、抛光后和热循环后进行测量。然后比较颜色变化（ΔEab）、透明度参数（TP）和对比度（CR）。固化后ΔEab的范围为3.8至10.2（8种复合材料的平均ΔEab = 6.4），观察者认为这是可察觉的。抛光导致ΔEab为1.9至4.5，8种复合材料中有5种可察觉。经过2000次热循环后，ΔE*ab为0.4至1.3。TP值在固化后趋于增加，在热循环后趋于降低（固化前范围为7.1至17.2）。所有复合材料固化后TP值的变化具有统计学意义（p<0.05）。CR值的变化与TP的透明度变化相似。尽管复合材料色号均指定为A2，但颜色坐标、TP和CR值、固化、抛光和热循环后的颜色和透明度变化因品牌而异。
