Designing visually optimal shade guides

Statement of problem. Dental shade guides do not provide a broad coverage of tooth colors. There is a need for shade guides that can provide closer color matches. Purpose. The purpose of this study was to propose and assess a visually optimal shade guide for tooth color matching. Material and methods. With the use of a spectrophotometric approach, the color distribution (L*a*b*) of 150 extracted human teeth and 3 commercially available shade guides (Vita Lumin V, Trubyte Bioform Color Order Shade Guide, and Vitapan 3D-Master Shade System) was measured. With the use of a hierarchical clustering approach, a series of shade guides was designed with a varying number of tabs. The average error (DeltaE) between colors from each shade guide and the extracted teeth was computed. Results. The proposed visually optimal shade guide had the smallest average error of all guides tested. The new guide achieved lower error with fewer shade tabs than the 3 commercial systems evaluated. Conclusion. Within the limitations of this study, it was demonstrated that a hierarchical clustering technique can be used to design a visually optimal shade guide for a given population with a flexible degree of control over the mean error and number of tabs.