The purpose of this study was to assess the coverage error and the coverage error percentage for two common commercial dental shade guides named VITA classical A1-D4 shade guide and VITA Toothguide 3D-MASTER. Totally, 197 dental students with intact maxillary anterior teeth were randomly selected to participate in the study. CIELAB values of the teeth were measured with a spectrophotometer. The teeth matched shades were selected by using the spectrophotometer. ∆E₀₀ and ∆E*_ab color differences between the matched shades and the teeth shades were calculated. The mean ∆E₀₀ and ∆E^*_ab values represented the coverage errors for the shade guides. The coverage error values were compared with the thresholds for perceptibility and acceptability using 1-sample t test (α = 0.05). To calculate the coverage error percentages for the shade guides, a color matching error for the shade guides was considered when the color difference value was greater than the thresholds. For VITA classical shade guide, the coverage error was 3.0 ± 1.2 (∆E₀₀) and 3.3 ± 1.3(∆E^*_ab) while the coverage error percentages ranged between 63.6% and 99.4%. For VITA 3D-MASTER guide, the coverage error was 2.5 ± 1.3 (∆E₀₀) and 2.9 ± 1.5 (∆E^*_ab) while the coverage error percentages ranged between 44.5% and 96.9%. Overall, the teeth were more reddish than their matched shades of the shade guides. Using these shade guides may cause inaccurate shade determination in the population studied due to their high coverage error and coverage error percentage values.

中文翻译：

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使用分光光度法评估两种常见商业牙科比色板的覆盖误差

本研究的目的是评估两种常见的商业牙科比色板 VITA 经典 A1-D4 色板和 VITA Toothguide 3D-MASTER 的覆盖率误差和覆盖率误差百分比。共有197名上颌前牙完整的牙科学生被随机选择参加研究。用分光光度计测量牙齿的 CIELAB 值。通过使用分光光度计选择牙齿匹配的色调。计算了匹配色调和牙齿色调之间的Δ E ₀₀和 Δ E* _ab色差。平均值 ∆ E ₀₀和 ∆ E ^* _ab值表示遮光板的覆盖误差。使用 1 样本t检验 ( α  = 0.05) 将覆盖误差值与可感知性和可接受性阈值进行比较。为了计算比色板的覆盖误差百分比，当色差值大于阈值时，考虑到比色板的颜色匹配错误。对于 VITA 经典比色板，覆盖误差为 3.0 ± 1.2 (Δ E ₀₀ ) 和 3.3 ± 1.3(Δ E ^* _ab )，而覆盖误差百分比介于 63.6% 和 99.4% 之间。对于 VITA 3D-MASTER 指南，覆盖误差为 2.5 ± 1.3 (Δ E ₀₀ ) 和 2.9 ± 1.5 (Δ E ^*_ab )，而覆盖错误百分比介于 44.5% 和 96.9% 之间。总体而言，牙齿比它们匹配的阴影指南的色调更红。由于它们的高覆盖误差和覆盖误差百分比值，使用这些色板可能会导致研究人群中的色度测定不准确。