Division of Operative Dentistry and Biomaterials, Department of Restorative Sciences, University of North Carolina School of Dentistry, Chapel Hill, North Carolina.
Operative Dentistry and Cariology, Faculty of Odontology, Division of Health Sciences, University of Iceland, Reykjavic, Iceland.
J Esthet Restor Dent. 2019 Mar;31(2):118-123. doi: 10.1111/jerd.12461. Epub 2019 Feb 23.
To estimate the time required for teeth to dehydrate and rehydrate and its relation to the accuracy of tooth shade selection.
Thirty-two participants were recruited, and color measurements were conducted using a spectrophotometer placed with a custom jig. After isolation, baseline measurements were made at 1, 2, 3, 5, 7, 10, and 15 min intervals to determine dehydration time. After mouth rinsing, measurements were made to determine rehydration time. CIEDE2000 values were obtained for color change between the baseline recordings and all intervals and compared to the 50:50% perceptibility and acceptability thresholds. Analysis of variance (anova) and Tukey test was used for multiple comparisons.
The tooth color changes were beyond the ΔE perceptibility threshold (0.8) within the first minute of dehydration (P > 0.0001). After the first minute, 87% of the teeth were beyond the ΔE perceptibility threshold (0.8), and 72% of the teeth were beyond the ΔE acceptability threshold (1.8). After 15 min of rehydration, 90% of the teeth were beyond the perceptibility threshold, and 65% were beyond the acceptability threshold.
Shade selection procedures should be carried out within the first minute and before teeth dehydrate by means of isolation. Teeth do not rehydrate within 15 min after rehydration.
Teeth dehydration has a negative impact on shade selection, which can affect the final esthetic outcome. Shade selection should be performed at the beginning of any restorative procedure.
评估牙齿脱水和复水所需的时间及其与牙齿比色选择准确性的关系。
招募了 32 名参与者，并使用带有定制夹具的分光光度计进行颜色测量。隔离后，在 1、2、3、5、7、10 和 15 分钟间隔进行基线测量，以确定脱水时间。漱口后，进行测量以确定复水时间。获取基线记录与所有间隔之间颜色变化的 CIEDE2000 值，并与 50:50%可感知性和可接受性阈值进行比较。使用方差分析（anova）和 Tukey 检验进行多重比较。
牙齿颜色变化在脱水的第一分钟内超过了 ΔE 可感知性阈值（0.8）（P > 0.0001）。在第一分钟之后，87%的牙齿超过了 ΔE 可感知性阈值（0.8），72%的牙齿超过了 ΔE 可接受性阈值（1.8）。复水 15 分钟后，90%的牙齿超过了可感知性阈值，65%的牙齿超过了可接受性阈值。
比色选择程序应在隔离后的第一分钟内进行，以避免牙齿脱水。在 15 分钟的复水后，牙齿不会完全复水。
牙齿脱水会对比色选择产生负面影响，从而影响最终的美观效果。比色选择应在任何修复程序开始时进行。
