Generally speaking, shade guide tabs are not spaced evenly with regards to whiteness. ShadeVision has implemented a mathematical calculation to identify the whiteness of a tooth with equidistant units of measurement.
Activate the "Show Whiteness" check box while in the "Average" shade view to display the “whiteness number” for the average dentin area of the tooth. This calculation is independent of the shade assignment for each tooth. This new whiteness calculation, based on value and chroma, can represent a numeric progression of whiteness.
Higher whiteness numbers indicate whiter teeth. For example, a tooth with a dentin shade of C4 might have a "Whiteness" of “W17”, whereas a tooth with a dentin shade of A1 might have a Whiteness of “W31”. This will be very useful for comparing before and after measurements to track the progress of bleaching.
NOTE: This feature is NOT intended as a quality control for matching the color of teeth. The sole intended use of this feature is to aid in tracking the progress of a tooth whitening process.
Select the tab Average in the Group Editor.
Activate Show Whiteness on the left side of the window underneath the list of Shade Guides.
In the tooth image, you see a whiteness number in curly brackets under the shade index. The numerical value indicates the level of white of the dentin and is based on value and chroma. The higher the number, the whiter the tooth.