ビデオディジタイザーを応用したシェードガイドと天然歯の測色

Abstract

This study was application of the computer and the video digitizer to colorimetry of the teeth of children. However, the chromatical values are not assured, because this equipment was developed for computergraphics. So in the region of crown color, the guaranteed degree and the way of mathematical conversion were researched. After establishing the way for conversion, VITA LUMIN shade guide, upper primary central incisors, and upper permanent central incisors were chromatically examined in CIE 1976 (L^*a^*b^*) Color Space by this system. 1. The guarantee of the chromatic values measured by this system in the region of crown color. The three color charts whose hue is 10YR, chromaticness is 3, and lightness is 6, 8, 9, were chosen as the three standard colors. When measured values were converted with each XYZ value, the value of color differrence between converted values and published values was 1.62 on the average. 2. The chromatic values of VITA LUMIN shade guide. The distribution range in the center was as follows. (L^*value : 60-80, H^*value : 80-112, C^*value : 11-25). The less the number of the shade guide was named, the lighter and the more yellowish. In comparison with A system, B system showed yellowish, C system became darker, and D system were low chromaticness. 3. The chromatic values of upper primary central incisors (upper A), and upper permanent central incisors (upper 1). The distribution range in which 95% cases were included was as follows. upper A……L^* : 62.2-84.6, H^* : 38.8-108.0, C^* : 0.6-22.2 upper 1……L^* : 57.9-91.4, H^* : 55.8-93.4, C^* : 8.7-28.0 4. The difference between the shade guide and the natural teeth a. Because the children's teeth were examined in this study, high brightness shade guide was insufficient. And the average hue of teeth was little redder than shade guide. b. The natural teeth only showed the correlation between L^* and C^* But the shade guide showed the correlation among all the cases. c. In the case of natural teeth, the lightness at central part was the highest. But in the case of the shade guide, the lightness and chromaticness decreased from the cervical part to the incisal edge.