Assessment of coverage error for two common commercial dental shade guides using a spectrophotometric method

Abstract

AbstractThe purpose of this study was to assess the coverage error and the coverage error percentage for two common commercial dental shade guides named VITA classical A1‐D4 shade guide and VITA Toothguide 3D‐MASTER. Totally, 197 dental students with intact maxillary anterior teeth were randomly selected to participate in the study. CIELAB values of the teeth were measured with a spectrophotometer. The teeth matched shades were selected by using the spectrophotometer. ∆E00 and ∆E*ab color differences between the matched shades and the teeth shades were calculated. The mean ∆E00 and ∆E*ab values represented the coverage errors for the shade guides. The coverage error values were compared with the thresholds for perceptibility and acceptability using 1‐sample t test (α = 0.05). To calculate the coverage error percentages for the shade guides, a color matching error for the shade guides was considered when the color difference value was greater than the thresholds. For VITA classical shade guide, the coverage error was 3.0 ± 1.2 (∆E00) and 3.3 ± 1.3(∆E*ab) while the coverage error percentages ranged between 63.6% and 99.4%. For VITA 3D‐MASTER guide, the coverage error was 2.5 ± 1.3 (∆E00) and 2.9 ± 1.5 (∆E*ab) while the coverage error percentages ranged between 44.5% and 96.9%. Overall, the teeth were more reddish than their matched shades of the shade guides. Using these shade guides may cause inaccurate shade determination in the population studied due to their high coverage error and coverage error percentage values.