Validation of Two Clinical Color Measuring Instruments for Use in Dental Research

Objective: There are several shade matching instruments developed for clinical use, but the validity of their use in dental research has not been thoroughly investigated. The objective of this study is to evaluate the accuracy of using two clinical color measuring instruments, VitaEasyshade and Spectroshade, against a referent laboratory color measuring instrument (Spectroradiometer PR670). Methods and materials: The validity and repeatability of the referent laboratory color measuring instrument was assessed using standard color patches with certified CIE L*a*b* values. 10% of the 240 color patches were randomly selected and measured ten times in a random order to test for repeatability. 16 metal ceramic specimens, fabricated from base metal alloy veneered with porcelain of different Vita Classic shades, were measured for L*a*b* values using the PR670, Vita EasyShade and the Spectroshade. The CIE L*a*b* values obtained from the three color measuring instruments were compared using repeated measures ANOVA and post hoc using the Bonferroni test. The color difference, CIEDE2000 (∆E ₀₀), between the gold standard (PR670) and the two color measuring instruments were also determined and compared against the known perceptible color difference. Results: L*a*b* values varied significantly between the three instruments. When comparing the mean ΔE ₀₀, the differences in values between PR670 and Spectroshade were not clinically significantly. However, the mean ΔE ₀₀ values between PR670 and Vita Easyshade were both clinically and statistically significant. Conclusion: The lack of clinical significance in values obtained from the SpectroShade when compared to those obtained by the PR670 suggests that the SpectroShade may be recommended for use in dental color research. Clinical significance: The SpectroShade instrument and PR670 spectroradiometer provided values that lacked clinical significance, suggesting that its use may be highly beneficial for clinical shade matching as well as color research.