Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, Granada, s/n 18071, Spain.
Houston Center for Biomaterials and Biomimetics (HCBB) & Department of Restorative Dentistry and Prosthodontics, University of Texas School of Dentistry at Houston, Houston, Texas.
J Esthet Restor Dent. 2018 Mar;30(2):E24-E30. doi: 10.1111/jerd.12373. Epub 2018 Feb 24.
To determine 50:50% perceptibility threshold (PT) and 50:50% acceptability threshold (AT) for computer-simulated samples of human gingiva using CIEDE2000 and CIELAB color difference formulas.
Each of the 60 pairs of simulated human gingiva was displayed on a calibrated monitor, together with three pairs of upper central incisors of different lightness. The color of gingiva left and right from the midline was compared. A total of 30 observers (15 dentists, 15 laypersons) participated in the study. CIEDE2000 and CIELAB formulas were used to calculate the thresholds and a Takagi-Sugeno-Kang Fuzzy Approximation model was used as fitting procedure. Paired t-test (α = 0.05) was used in evaluation of statistical significance of differences.
The PT and AT for CIEDE2000 and 95% confidence intervals were 1.1 [0.4, 1.7] and 2.8 [1.8, 4.0], respectively. Corresponding CIELAB values were 1.7 [0.2, 2.6] and 3.7 [2.1, 5.7]. Significant differences (P < .01) were recorded between PT and AT, between the corresponding threshold values in CIEDE2000 and CIELAB formulas as well as between dentists and laypersons.
The difference between the perceptibility and acceptability threshold for gingiva was statistically significant in both CIEDE2000 and CIELAB. The same was true for differences between the corresponding thresholds using two color difference formulas, and between dentists and laypersons. Visual thresholds of human gingiva were not dependent upon lightness of adjacent teeth. Overall, CIEDE2000 color difference formula provided better fit than CIELAB formula in the evaluation of color difference thresholds of human gingiva.
The data on visual thresholds for healthy human gingiva can be used as quality control tool/guide for selection and evaluation of dental materials, interpretation of color-related findings in clinical dentistry and research, and for standardization in dentistry. It is of particular value that this study was designed based on in-vivo color evaluation of healthy keratinized gingiva of subjects of different ethnicities, age groups, and gender.
使用 CIEDE2000 和 CIELAB 色差公式确定计算机模拟的人牙龈样本的 50:50%可感知性阈值 (PT) 和 50:50%可接受性阈值 (AT)。
每对 60 个人工模拟的人牙龈与三对不同明度的上颌中切牙一起显示在校准的监视器上。从中线向左和向右比较牙龈的颜色。共有 30 名观察者（15 名牙医，15 名非专业人士）参与了这项研究。使用 CIEDE2000 和 CIELAB 公式计算阈值，并使用 Takagi-Sugeno-Kang 模糊逼近模型作为拟合过程。使用配对 t 检验（α=0.05）评估差异的统计学意义。
CIEDE2000 的 PT 和 AT 及其 95%置信区间分别为 1.1 [0.4, 1.7] 和 2.8 [1.8, 4.0]。相应的 CIELAB 值分别为 1.7 [0.2, 2.6] 和 3.7 [2.1, 5.7]。PT 和 AT、CIEDE2000 和 CIELAB 公式中相应阈值之间以及牙医和非专业人士之间均记录到显著差异（P<.01）。
CIEDE2000 和 CIELAB 中牙龈的可感知性和可接受性阈值之间存在统计学显著差异。两种色差公式对应的阈值之间以及牙医和非专业人士之间也存在差异。人牙龈的视觉阈值不依赖于相邻牙齿的明度。总体而言，CIEDE2000 色差公式在评价人牙龈颜色差异阈值方面比 CIELAB 公式提供了更好的拟合度。
健康人牙龈的视觉阈值数据可用作牙科材料选择和评估、临床牙科和研究中颜色相关发现的解释以及牙科标准化的质量控制工具/指南。特别有价值的是，这项研究是基于对不同种族、年龄组和性别人体角化牙龈的活体颜色评估而设计的。
