Visual Assessment of Color Difference.

描述（由申请人提供）：自然牙齿、皮肤、牙齿和颌面材料光学特性的扩展知识和临床应用是改善口腔内和口腔外修复过程中颜色复制的长期目标。需要牙齿修复治疗和/或面部假体重建的患者可以随着牙齿颜色复制过程的进步而改善生活质量。通过应用已建立的心理物理学方法，以下具体目标旨在提高牙科颜色复制过程的准确性：(1)确定色差公式，该公式为人类观察者对微小色差的感知和可接受性提供最佳指标；(2)确定人类牙列颜色范围内可感知和可接受色差的差异和大小。方法：对50名受试者进行前牙颜色测量，以确定人类牙列的颜色范围（实验一）。这些信息将用于规划标准“牙齿”和比较“修复”对之间的颜色差异（实验二的第一、二、三阶段）。将招募三组不同的24名受试者，每个阶段一个。受试者人群由四个观察组组成：牙医、辅助人员、技术人员和患者。受试者将评估牙齿/修复体对的可感知和可接受的颜色差异，这些牙齿/修复体对呈现为(1)由不透明瓷制成的磁盘-阶段1，(2)在计算机屏幕上作为磁盘模型-阶段2，或(3)在计算机面部模型上作为三维相邻的“牙齿”和“冠”模型-阶段3。根据我们的初步研究，标准和比较的色差分布分别为0、0.5、1、1.5、3、4.5 delta Es。色差的大小取决于L*a*或b*方向的变化。统计分析：对每个受试者的数据生成受试者操作者特征曲线（receiver operator characteristic curve， ROC）以及可感知性和可接受性的各种色差公式。曲线下的面积将被计算并排序。CMC色差公式的最佳因子将通过设计的实验装置来确定。采用重复测量方差分析（alpha= 0.05）来确定观察组间拟合的统计学显著性；CIELAB色差公式和最优CMC色差公式的可感知性和可接受性。将为每个观察组和每个公式确定50:50的可感知性和可接受性delta E点。Tukey's Studentized Range Test （alpha= 0.05）将被用作事后检验。卡方检验将比较第一阶段和第二阶段的数据，以评估计算机与实际样本模型的有效性。

DESCRIPTION (provided by applicant): Expanded knowledge and clinical application of the optical properties of natural teeth, skin, dental and maxillofacial materials are necessary as a long-range goal for improved color replication involving both intra- and extra-oral restorative procedures. Patients needing restorative dental treatment and/or facial prosthetic reconstruction can experience improved quality of life with the advancement of the dental color replication process. By applying established psychophysical methodology, the following specific aims target improving the accuracy of the color replication process for dentistry: (1) To determine the color difference formula that provides the best indicator for perceptibility and acceptability of small color differences by human observers and (2) To determine the difference and magnitude of perceptible and acceptable color differences within the color range of human dentition. Methods: Anterior tooth color measurements will be taken from 50 subjects to determine the range of color of human dentition (Experiment I). This information will be used to plan color differences between standard "tooth" and comparison "restoration" pairs (Phases I, II, III of Experiment II). Three different sets of 24 subjects will be recruited, one for each phase. The subject population consists of four observer groups: dentists, auxiliaries, technicians and patients. Subjects will evaluate perceivable and acceptable color differences among the tooth/restoration pairs that are presented (1) as disks fabricated with opaque porcelain - Phase I, (2) as disk models on a computer screen - Phase II, or (3) as three-dimensional adjacent "tooth" and "crown" models on a computer face model - Phase III. From our preliminary study, the proposed distribution of the color difference between standard and comparisons are 0,0.5,1, 1.5, 3, 4.5 delta Es. The magnitude of the color difference will be due to variations according to either a change in direction of L*a* or b*. Statistical analyses: The receiver operator characteristics curve (ROC) will be generated for each subject's data and the various color difference formulas for perceptibility and acceptability. The area under the curves will be calculated and ranked. The optimal factor for the CMC color difference formula will be determined using designed experimental sets. A repeated measures analysis of variance (alpha= 0.05) will be applied to determine statistical significance of fit among the observer groups; the CIELAB color difference formula and the optimal CMC color difference formula for both perceptibility and acceptability. The 50:50 delta E point for perceptibility and acceptability will be determined for each observer group and each formula. Tukey's Studentized Range Test (alpha=O.05) will be used as a post hoc test. A chi-square test will compare data from phase I and II to assess validation of the computer with the actual sample model.