Color Difference Thresholds for Dentistry
Credible numerical values for visually perceptible and acceptable color differences, 50:50% perceptibility threshold (PT) and 50:50% acceptability threshold (AT) are needed in order to quantify and define color match in dentistry. A prospective multi-center study, performed on different continents, combined visual and instrumental methods on monochromatic ceramic specimens fabricated within the tooth color range. A total of 3 sets of specimen pairs were created, with 20 pairs per set. A total of 175 individuals with normal color vision (25 per research site) participated in visual judgments: dentists, dental students, dental auxiliaries, dental technicians, and laypersons. The frequency level of perceived/accepted color differences was determined. Takagi-Sugeno-Kang (TSK) Fuzzy Approximation was used to perform the fitting of the percentages of answers against the instrumentally measured color differences: A 50:50% perceptibility and acceptability thresholds were significantly different. Observer groups and sites showed a high level of statistical difference in all thresholds. Based on the results, a Eab=2.7 is proposed as 50:50% acceptability threshold in dentistry.
To understand the role of color difference thresholds in quality control, selection and evaluation of dental materials, and interpretation of visual and instrumental findings in clinical dentistry, dental research, and subsequent standardization.
Rade D. Paravina, DDS, MS, PhD is a tenured Professor at the University of Texas School of Dentistry at Houston and Director of Houston Center for Biomaterials and Biomimetics (HCBB). He also holds the Ralph C. Cooley, DDS Distinguished Professorship in Biomaterials, an endowment created by world-renowned heart surgeon Denton A. Cooley, MD. Dr. Paravina has authored/co-edited two books, two software programs, one educational CD, and more than 200 other peer-reviewed publications.
Dr. Paravina designed/developed several dental products and tests. Together with Vita Zahnfabrik he designed two shade guides, Linearguide 3D Master and Bleachedguide 3D Master. He has developed Dental Color Matcher, a free online and offline educational and training program for esthetic dentistry, and the scientific protocol for evaluating "chameleon effect" of dental materials.
Dr. Paravina is Founder and Past President of the Society for Color and Appearance in Dentistry (SCAD). He is a recipient of the 2011 E. B. Clark Award, SCAD award for lifetime achievement, and the 2014 Jerome M. and Dorothy Schweitzer Research Award of the Greater New York Academy of Prosthodontics. He serves as editor of the Color and Appearance in Dentistry, a permanent bi-annual issue of the Journal of Esthetic and Restorative Dentistry, and editorial board member for the Journal of Dentistry, Clinical Oral Investigations, Journal of Prosthodontics, Journal of Esthetic and Restorative Dentistry, and the American Journal of Dentistry.
Dr. Paravina lectures nationally and internationally on various topics associated with color and appearance in esthetic dentistry.
