Sagel Paul A, Gerlach Robert W
The Procter & Gamble Company, Mason, OH 45040, USA.
Am J Dent. 2007 Sep;20 Spec No A:7A-14A.
The development of novel peroxide-based bleaching systems during the last several years has prompted the need for robust clinical methods to evaluate whitening response. Advances in digital camera technology and image analysis software provided the basis for an instrumental method to assess tooth color closely following a technique previously used to quantify plaque on tooth surfaces. In vitro and in vivo research was conducted to determine reproducibility of color measurements using this objective, digital imaging method.
Each of the 16 tabs in a standard shade guide system was mounted in a jig, and measurement reproducibility was assessed in vitro from paired digital images collected over a 2-day period. Separately, clinical measurement reproducibility was assessed in vivo from paired images of 14 healthy adult volunteers collected over a 2-day period. From these digital images, mean L*, a*, and b* color values were derived for each of the 16 individual shade tabs (in vitro study), or the facial surfaces of the maxillary six anterior teeth (in vivo study) of the 14 subjects. For each data set, variability was determined using ANOVA, and between-visit color measurement reliability was determined from intra-class correlation coefficients (ICCs).
In the in vitro study, shade tab yellowness (b*) ranged from 9.0-18.6, lightness (L*) ranged from 63.4-76.2, and redness (a*) ranged from 0.9-3.6. Overall daily means differed by 0.08 units or less, and intra-class correlations for the image pairs were 0.998 for L*, 0.996 for a* and 0.998 for b*. In the in vivo assessment, the 14 volunteers exhibited considerable range in tooth color. Yellowness (b*) ranged from 13.5-21.3, lightness (L*) ranged from 69.2-78.0, and redness (a*) ranged from 5.2-8.8. Clinical measurement of mean tooth color from digital images was highly reproducible across visits. Intra-class correlations for the image pairs were 0.989 for b*, 0.970 for L* and 0.979 for a*.
在过去几年中，新型过氧化物基漂白系统的发展促使人们需要可靠的临床方法来评估美白效果。数码相机技术和图像分析软件的进步为一种仪器方法提供了基础，该方法可紧密跟踪先前用于量化牙齿表面菌斑的技术来评估牙齿颜色。进行了体外和体内研究，以确定使用这种客观的数字成像方法进行颜色测量的可重复性。
将标准比色板系统中的16个色片分别安装在一个夹具中，并通过在两天内收集的成对数字图像在体外评估测量的可重复性。另外，通过在两天内收集的14名健康成年志愿者的成对图像在体内评估临床测量的可重复性。从这些数字图像中，得出16个单个色片（体外研究）或14名受试者上颌六颗前牙的唇面（体内研究）各自的平均L*、a和b颜色值。对于每个数据集，使用方差分析确定变异性，并通过组内相关系数（ICC）确定不同就诊间颜色测量的可靠性。
在体外研究中，色片的黄度（b*）范围为9.0 - 18.6，亮度（L*）范围为63.4 - 76.2，红度（a*）范围为0.9 - 3.6。总体每日平均值相差0.08个单位或更少，图像对的组内相关性对于L为0.998，对于a为0.996，对于b为0.998。在体内评估中，14名志愿者的牙齿颜色范围相当大。黄度（b）范围为13.5 - 21.3，亮度（L*）范围为69.2 - 78.0，红度（a*）范围为5.2 - 8.8。通过数字图像对平均牙齿颜色进行的临床测量在不同就诊间具有高度可重复性。图像对的组内相关性对于b为0.989，对于L为0.970，对于a*为0.979。
