This study investigates the validation of a tooth imaging system in assessing changes in tooth whiteness in clinical dental trials. Sixteen male and female subjects aged between 18-70 years participated in the study and were divided into two groups. The control group was given a non-whitening toothpaste, whereas the test group used a tooth-whitening system for 14 days. Five Images were taken at the beginning of the trial (baseline), 4th, 7th, 11th and 14th day of the treatment. Camera RGB values were transformed to CIELAB space, and colour differences and three whiteness indices were calculated. The test group showed obvious changes in colour coordinates and whiteness indices over the two week period, while the control group kept stable in tooth colour. At the meantime of image capture, visual assessments by a dentist were done in a typical clinical surgery. The comparison result between the camera measurements and visual assessments also proved the validation of the tooth-imaging system for measuring tooth-whiteness.
W. Luo, S. Westland, R. Ellwood, P. Brunton, I. Pretty, "Validation of a Tooth-Imaging System in Tooth-Whitening Trials" in Proc. IS&T CGIV 2006 3rd European Conf. on Colour in Graphics, Imaging, and Vision, 2006, pp 40 - 43, https://doi.org/10.2352/CGIV.2006.3.1.art00008