Abstract:

Objective Based on the HSB color model, the hue(H), saturation(S) and brightness(B) values of each region of the teeth were measured to explore the color change rule. Methods A total of 65 patients with 65 right maxillary central incisors were included in this study. The color of the cervical, middle and incisal regions of the right maxillary central incisors were measured using a color picker tool, avoiding reflective zones. The overall color parameters and the relative differences between each region and the overall tooth were calculated. Finally, results of the calculations were tallied to find rules of color change in three regions of the teeth. Results The results showed that in the same right maxillary central incisor, the cervical, middle and incisal regions differed in hue, saturation, and brightness compared to the overall color parameters of the teeth. In the same right maxillary central incisor, the differences between the hue of the middle region and the hue of the other two regions were statistically significant. Moreover, the differences in saturation between the cervical, middle and incisal regions were statistically significant. The difference in brightness between the cervical region and incisal region, and the difference in brightness between the middle region and the incisal region were also statistically significant. Conclusion There is variability in the color of three regions of the right maxillary central incisor. In the same right maxillary central incisor, the middle region has the most yellowish hue; the hue of the the cervical region and the incisal region are reddish. The cervical region is the most saturated; the middle region is the second most saturated, and the incisal region is the least saturated. The brightness of the incisal region is the lowest.

Key words: HSB color model, right maxillary central incisor, tooth color, change rule