Threshold Values for the Perception of Color Changes in Human Teeth

The aim of the present study was to assess the threshold values for color changes on the level of the tooth separately for laypeople, dentists, and dental technicians. Standardized presentations were made of five cases (maxilla, left to right lateral incisors) with the gingiva and teeth separated. The color parameters L (lightness), a, and b (chroma) (CIE L*a*b* parameters) of the tooth layers were adjusted to induce darker and lighter colors. In the presentations, the left part of the pictures (maxillary right central and lateral incisors) was unchanged, whereas the right part was modified. A group of 10 dentists, 10 dental technicians, and 10 laypeople evaluated the color differences between the pictures. The median threshold values were 1.8 (laypeople), 1.8 (dental technicians), and 1.9 (dentists). The overall ΔE amounted to 1.8.