Colorimetric (CIEDE2000) comparison between two shade guides used for visual evaluation of tooth whitening efficacy

Abstract

Introduction/Objective The objective of this study was to perform colorimetric comparison between two shade guides used for visual tooth whitening monitoring. Methods VITA Bleachedguide 3D-Master (BG) and value scale of VITA classical A1-D4 (VC) were evaluated (n = 3) using a non-contact spectroradiometer. Ranges, distribution, and correlation among color parameters were evaluated using CIEDE2000 color difference formula. In addition, optimized whiteness index for dentistry (WID), and Yellowness Index E313 (YI) were analyzed. ANOVA and Fisher’s PLSD test at a 0.05 level of significance were used in statistical analysis. Results The lightness (L’), chroma (C’), and hue (h’) ranges for BG were 20.4, 25.9, and 19.1, respectively. The corresponding ranges for VC were 15.3, 10.9, and 20.6. R2 values for individual color coordinate/tab arrangement were higher for BG than VC. The same is true for R2 values of pairs of color coordinates for BG/VC: L’C’ = 0.89/0.33, L’h’ = 0.88/0.53, and C’h’ = 0.70/0.51. BG also exhibited better agreement between the manufacturer’s tab arrangement with ΔE’, WID and YI. The ΔE’ between the lightest and the darkest BG and VC tab were 20.6 and 13.2, respectively. The average ΔE’ among the adjacent tabs were 1.9 (0.5) for BG (corresponding to two shade guide units, SGU) and 3.0 (1.0) for VC (1 SGU). Conclusion VITA Bleachedguide 3D-Master exhibited wider L’, C’, ΔE’, WID, and YI ranges compared to value scale of VITA classical A1-D4 shade guide and better distribution of evaluated color parameters. This, along with the presence of several shades lighter than B1 of VC, recommends the use of BG for visual evaluation of tooth whitening efficacy.