Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, S/N 18071, Granada, Spain.
Department of Stomatology, Faculty of Dentistry, University of Granada, Campus de Cartuja S/N, Granada, 18071, Spain.
J Dent. 2021 Feb;105:103560. doi: 10.1016/j.jdent.2020.103560. Epub 2021 Jan 6.
To determine in-vivo chromatic and whiteness changes produced by short-term dental dehydration.
Spectral reflectance of 452 upper incisors (226 centrals and 226 laterals) of 113 participants were measured using a spectroradiometer at baseline and after short-term dehydration (minutes 2, 4, 6, 8 and 10). CIE Lab* color coordinates (L*, a*, b*, C* and h) and whiteness index for dentistry (WI) were calculated. Color differences (ΔE, ΔE) and whiteness differences (ΔWI) were computed and interpreted based on their respective 50:50% perceptibility (PT) and acceptability thresholds (AT). Statistical analysis was performed using the related samples Wilcoxon signed-rank test.
L* showed an increasing trend with dehydration, while a*, b*, C* and h have a decreasing tendency. All chromatic coordinates showed statistically significant differences (p < 0.003) at each interval of dehydration compared with baseline, except a* for all teeth. For ΔE and ΔE values were higher than PT after 2 min of teeth dehydration and higher than AT after 6 and 8 min, respectively. The percentage of teeth exceeding corresponding PT was higher than 50% after 2 min. WI index increased with dehydration time, while whiteness differences were clinically perceptible after 4 min. Statistically significant differences were found for WI between all dehydration intervals (except 8-10 min). The percentage of teeth exceeding whiteness PT was higher than 50% after 6 min of teeth dehydration.
Short-term dental dehydration produces clinically unacceptable changes in tooth color and clinically perceptible increase in tooth whiteness level.
Clinical shade matching must be done within the first two minutes of any clinical procedure that requires precise chromatic determination but implies a risk of tooth dehydration.
确定短期牙齿脱水引起的体内色度和白度变化。
使用分光光度计在基线和短期脱水后（2、4、6、8 和 10 分钟）测量 113 名参与者的 452 颗上颌切牙（226 颗中切牙和 226 颗侧切牙）的光谱反射率。计算 CIE Lab颜色坐标（L、a*、b*、C*和 h）和牙科白度指数（WI）。根据各自的 50:50%可察觉性（PT）和可接受性阈值（AT）计算和解释颜色差异（ΔE、ΔE）和白度差异（ΔWI）。使用相关样本 Wilcoxon 符号秩检验进行统计分析。
L随着脱水呈上升趋势，而 a、b*、C和 h 呈下降趋势。与基线相比，所有色度坐标在脱水的每个间隔都显示出统计学上的显著差异（p<0.003），除了所有牙齿的 a。对于 ΔE 和 ΔE 值，在牙齿脱水 2 分钟后高于 PT，在 6 和 8 分钟后高于 AT。超过相应 PT 的牙齿百分比高于 50%，在 2 分钟后。WI 指数随脱水时间的增加而增加，而在 4 分钟后白度差异具有临床可察觉性。WI 之间在所有脱水间隔均存在统计学差异（除 8-10 分钟外）。在牙齿脱水 6 分钟后，超过白度 PT 的牙齿百分比高于 50%。
短期牙齿脱水会导致牙齿颜色出现临床不可接受的变化，并使牙齿白度水平明显增加。
在任何需要精确色度测定但意味着牙齿脱水风险的临床操作的前两分钟内，必须进行临床比色匹配。
