In this study, various whiteness and yellowness indices were compared with regard to their ability to measure the perceived whiteness of human teeth. Psychophysical experiments were conducted by 80 observers on tooth whiteness perception under typical clinical test conditions. The Pearson correlation coefficient and ‘per-cent-wrong decision’ criterion were used to determine the best index for tooth whiteness measurement. The results confirmed the findings of a previous study that a modified form of the CIE Whiteness Index formula is appropriate for the prediction of tooth whiteness.
W. Luo, S. Westland, I. Pretty, R. Ellwood, "Testing the Performance of a Modified Whiteness Formula for Dentistry" in Proc. IS&T 13th Color and Imaging Conf., 2005, pp 59 - 62, https://doi.org/10.2352/CIC.2005.13.1.art00011