Assessing tooth color differences in digital facial portraits

Area of Science:

• Dental Aesthetics
• Color Science
• Human Perception

Background:

• Color perception is influenced by background color and luminance.
• Previous tooth color difference studies often overlooked viewing context.
• Skin and gingival color may affect tooth color judgments.

Purpose of the Study:

• To test if skin/gingival color differences influence tooth color difference judgments.
• To determine perceptibility and acceptability thresholds for tooth color differences within varying contexts.
• To investigate the impact of portrait ethnicity on tooth color perception.

Main Methods:

• A signal detection paradigm was used with 10 participants.
• Participants evaluated 500 facial portraits (African-American and Caucasian).
• Portraits varied in the direction (CIELAB +L*, +a*, +b*) and magnitude of tooth color difference.

Main Results:

• Participants showed significantly lower sensitivity to lightness (L*) tooth color differences in Caucasian portraits.
• Perceptibility and acceptability thresholds were often not statistically different.
• Sensitivity varied based on color difference direction and portrait ethnicity.

Conclusions:

• Facial context, specifically skin and gingival color, demonstrably influences tooth color perception.
• The +L* direction of tooth color difference is perceived less readily in Caucasian portraits.
• Context-dependent perception suggests a need to incorporate viewing conditions into dental shade assessment standards.