| Color selection and color matching are the key to success in the maxillofacial restorations. For the satisfied result of prostheses, there are two problems which have to be solved at first: ①how to definite the character and range of the maxillofacial complexion; ②how to select the color exactly. So this study aims at: ①investigating the main factors which affect the facial skin color and the range of the maxillofacial complexion in Sichuanese; ②designing and manufacturing the maxillofacial derma shade guide matching to complexion of Chinese, based on the normal range of the Chinese facial complexion; ③applying the digital image technique to color selection of maxillofacial derma. Part One The elementary study on Chinese Maxillofacial Complexion This study made color measurements of the Chinese maxillofacial derma in Sichuan by means of Minolta Chroma Meter CR-100, in order to have a basic understanding of the influence of the anatomic region, age, sex, occupation and nationality on the maxillofacial dermal color. And the results showed: 1. Maxillofacial complexion in the Han nationality was symmetrical. 2. The chroma L~*a~*b~* of frontal area, temple area, zygomatic area, cheek area, nasal area, labrum area and chin area were different. There were the highest L~* and the lowest a~* in the cheek area, the lowest L~* and b~* in the labrum, the highest a* in the chin area, the highest b* in the temple area. 3. The color of the maxillofacial derma was related to sex. Male had the lower L* and b* value and the higher a* value than female did. 4. The maxillofacial chroma L* and a* were related to age negatively, and b* was related to age positively. 5. Compared with the indoor workers, the outdoor workers had lower L* value and higher a*,b* value. 6. There were significant different of maxillofacial skin chroma L* and a* among the Han nationality, the Tibetan and the Qiang nationality , due to the highest L* and the lowest a* in the Han nationality . There was no significant difference of chroma b* among the three nationalities. 7. The 95% normal range of Chinese maxillofacial skin chroma in Sichuan were: Y:19.19~33.81;x:0.366~0.396;y:0.354~0.374;L*:51.34~65.34;a*:6.05~14.59;b*:14.32~20.74;C*ab:17.22~23.68;H0ab:0.82~1.26. Part Two The design, manufacture and application to the maxillofacial derma shade guide This study designed the maxillofacial derma shade guide within the range of Chinese maxillofacail complexion, according to the chromatic distribution of VITAPAN 3D-MASTER, and manufactured the 22 pieces of maxillofacial derma shade guide by lithography. The degree of manufacturing accuracy was 1.55ΔE. Base on the measurement of the skin color of the zygomatic area with the self-made derma shade guide, the results showed that there was average 3.02ΔE between the shade guide value and the colorimeter value, so that the chroma of this derma shade guide coincided with the chroma of the Chinese maxillofacial derma on the whole.This study collected the images of the derma shade guide and the maxillofacial derma by means of a CCD video camera and a Canon digital camera. We measured the color by CorelDRAW software, and compared the chroma value coming from computer with the value from colorimeter, in order to evaluate the reliability of the digital imaging technique. The results showed: 1. There was a high correlation between the chroma value coming from CCD video camera and the value from colorimeter, and at least 2.6ΔE difference between them after calibration . 2. The best condition to shoot the images was: light source –two 40W tungsten lamp, shooting distance –10cm, custom white balance, shutter speed –1/125, aperture –3.5. 3. There was a high correlation between the chroma value coming from digital camera and the value from colorimeter, and at least 2.5ΔE difference between them after calibration. These results gave us some instruction on the color selection and color matching of maxiollfacial prostheses in clinic, and provided a theoretical base for color selection by digital image, and provided a base on derma shade guide which matched well to complexion of Chinese. In addition, the development of new material matching the complexion will benefit from these results. |
