Perceptibility and Acceptability Thresholds for Color Differences in Ceramic Shade Tabs: A Comparison Between...

The aim of this study was to evaluate the 50%:50% perceptibility thresholds (PT) and acceptability thresholds (AT) for color differences in ceramic shade tabs observed by dentists and patients using CIEDE2000 color difference formula.

Twenty-two combinations of ceramic shade tabs from the VITA 3D Master shade guide were assembled to be used for the visual comparison analyses. The color difference between each shade tab pair was numerically determined by spectrophotometry using the VITA EasyShade V, and calculated using the CIEDE2000 formula (ΔE00). Twenty dentists and twenty patients were recruited for this study. All participants performed the visual assessment of the provided shade tab pairs under D65 illumination and a grey background, and requested to determine if they could perceive a color difference between them (PT) and whether they considered the combination clinically acceptable (AT). The correlation between numeric data of color difference between the shade tabs, and the perceptibility and acceptability thresholds given by the participants was analyzed by logistic regression (α=0.05; β=0.0085).

The PT for dentists was ΔE00= 2.29, and ΔE00= 2.27 for patients. The AT for dentists was ΔE00=2,41, and ΔE00=2,83 for patients. The results showed a statistically significant difference between PT and AT thresholds for both dentists and patients. However, there was no statistically significant differences in PT (p=0.39) or AT (p=0.54) between patients and dentists.

Within the limitations of this study, it was possible to conclude that while the PT and AT vary significantly within each group, they are statistically similar between dentists and patients when discriminating color differences in ceramic tabs. Key words:Color difference, esthetic, aesthetic, spectrophotometry, CIEDE2000.