Reliability of shade selection using an intraoral spectrophotometer

Abstract

In this study, we evaluate the accuracy and reproducibility of human tooth shade selection using a digital spectrophotometer. Variability among examiners and illumination conditions were tested for possible influence on measurement reproducibility. Fifteen intact anterior teeth of 15 subjects were evaluated for their shade using a digital spectrophotometer (Crystaleye, Olympus, Tokyo, Japan) by two examiners under the same light conditions representing a dental laboratory situation. Each examiner performed the measurement ten times on the labial surface of each tooth containing three evaluation sides (cervical, body, incisal). Commission International on Illumination color space values for L* (lightness), a* (red/green), and b* (yellow/blue) were obtained from each evaluated side. Examiner 2 repeated the measurements of the same subjects under different light conditions (i.e., a dental unit with a chairside lamp). To describe measurement precision, the mean color difference from the mean metric was used. The computed confidence interval (CI) value 5.228 (4.6598-5.8615) reflected (represented) the validity of the measurements. Least square mean analysis of the values obtained by examiners 1 and 2 or under different illumination conditions revealed no statistically significant differences (CI = 95%). Within the limits of the present study, the accuracy and reproducibility of dental shade selection using the tested spectrophotometer with respect to examiner and illumination conditions reflected the reliability of this device. This study suggests that the tested spectrophotometer can be recommended for the clinical application of shade selection.

Investigations on the effects of mouthrinses on the colour stability and surface roughness of different dental bioceramics

“…In this study, spectrophotometry was used in which the results were automatically provided through a coordinate system (CIE L * a * b * ) 11213334. Ceramic materials having ΔE values greater than 3.3 are clinically unacceptable 1123.…”

Actual Methods of Color Measurement: A Systematic Review

“…Sarafianou ve ark., bu cihazların farklı aydınlatma koşullarındaki tekrarlanabilirliklerini yetersiz bulurken; Witkowski ve ark., Crystaleye cihazının farklı aydınlatmalarda ve farklı gözlemciler tarafından kullanılsa bile tutarlı sonuçlar verdiğini belirtmişlerdir. 66,68 Imbery ve ark. ile Khurana ve ark., tam yüzey ölçümü yapan cihazları (SpectroShade Micro ve Crystaleye); spot ölçümü yapan cihazlardan (Easyshade Compact, Shade-X) daha üstün bulmuş; bunun prob çapıyla orantılı olarak sınırlı bölgenin renk ölçümünün sonuçlar arası farklılıklara neden olabileceğini belirtmişlerdir.…”

Reliability of shade selection using an intraoral spectrophotometer: common mistakes in reliability analysis

“…As the authors point out in their conclusion, the accuracy and reproducibility of dental shade selection using the tested spectrophotometer with respect to examiner and illumination conditions reflected the reliability of this device [1]. A narrow CI has nothing to do with accuracy.…”

“…They report the mean colour difference from the mean metric for measurement precision (reliability)! Also, least square test was used to assess inter-and intra-observer reliability [1]. Why did the authors not use well-known statistical tests for reliability analysis such as intra-class correlation coefficient for quantitative variables, weighted kappa for qualitative ones [2][3][4][5] or other methods such as coefficient of variance for repeatability [2][3][4][5], considering that the mean of the variables and using paired t test, least square test or correlation coefficient (r) are among the common mistakes in reliability analysis [2][3][4][5]?…”