贵州省氟斑牙前牙色度值的测量分析

背景：在口腔烤瓷修复中应用维他经典比色板和维他三维能手比色板比色时不能完全覆盖所有天然牙颜色构成的空间范围，对氟斑牙色度的覆盖范围更少。目的：分析贵州省氟斑牙色度值的分布规律和特征及与正常牙色度值分布的差别。方法：从贵州省氟中毒人群中随机抽取氟斑牙患者317例作为实验组，共计634颗上颌中切牙；随机抽取204名健康人群的正常天然牙作为对照组，共记408颗上颌中切牙，采用国际照明委员会(CIE)推荐的CIE_1976(L*a*b*)表色系统，用Shade Eye-NCC电脑比色仪测定其色度学各要素(L*、a*、b*)值。结果与结论：实验组氟斑牙上颌中切牙色度值范围较对照组大，其中氟斑牙明度均值L*显著小于对照组(P < 0.05)，a*、b*均值明显高于对照组(P < 0.05)。实验组氟斑牙上颌中切牙9个区明度L*值在颈部Ⅱ区最高，切部Ⅸ区最低，从颈部、中部到切部逐渐降低；唇面近中1/3的a*、b*值均大于远中1/3，且同一受试者左右两侧中切牙的颜色参数差异无显著性意义(P < 0.05)。表明与与天然牙相比，氟斑牙色度值分布较为松散，色度学各要素分布范围广，颜色较正常牙暗且偏红偏黄。

Chroma values of maxillary central incisors in Guizhou residents with dental fluorosis

BACKGROUND:In shade matching of ceramic restoration, the color range of Vitapan classic shade guide and Vitapan 3D-Master shade guide both cannot cover all that of natural teeth，and cover even less the color space of dental fluorosis teeth.OBJECTIVE:To analyze the characteristics and distribution of dental fluorosis chroma value and to further compare the differences of chroma values between dental fluorosis and normal teeth from Guizhou residents.METHODS:A total of 317 dental fluorosis patients with 634 maxillary central incisors were randomly selected as experimental group, and 204 healthy normal people with 408 maxillary central incisors were randomly selected as control group. The tooth color was measured by a computer-aided Shade-Eye NCC colorimeter, and expressed in terms of three coordinate values (L*, a*, b*) of the CIE-1976-Lab color system recommended by International Commission on Illumination.RESULTS AND CONCLUSION:The chroma value of maxillary central incisors in the experimental group (dental fluorosis) was wider than that in the control group (normal teeth) and the L* value in the experimental group was significantly lower than that in the control group (P < 0.05), while the a* value and b* value in the experimental group were both obviously higher than those in the control group (P < 0.05). As for dental fluorosis, the L* value in cervical Ⅱ region was the highest among nine regions, and that in incisal Ⅸ region was the lowest. The L* value showed a diminishing trend from cervical, central region to incisal region. While a* value and b* value in the mesial 1/3 region of teeth lips face were both higher than those in the distal 1/3 region. There was no significant difference was in the chroma values of maxillary incisors between the left and the right for the same subject (P > 0.05). These results suggest that compared with normal teeth, the chroma-value distribution of dental fluorosis is more dispersive and wider, besides, the corresponding color is dark, redder and yellower.