CIEDE2000 lightness, chroma and hue human gingiva thresholds.

Area of Science:

• Dental Aesthetics
• Color Science
• Psychophysics

Background:

• Accurate color assessment is crucial in dentistry, particularly for gingival tissues.
• Existing color difference thresholds (CIEDE2000) may not be specific to human gingiva.
• Understanding gingival color perception is vital for shade matching and material selection.

Purpose of the Study:

• To establish the visual 50:50% perceptibility threshold (PT) and acceptability threshold (AT) for lightness (L'), chroma (C'), and hue (H') of human gingiva.
• To compare observer sensitivity to changes in gingival lightness, chroma, and hue.
• To provide specific color difference thresholds for gingival evaluations.

Main Methods:

• A psychophysical experiment using simulated gingival images on a calibrated display.
• A 20-observer panel (dentists and laypersons) evaluated lightness, chroma, and hue subsets.
• Takagi-Sugeno-Kang (TSK) Fuzzy Approximation model and t-test were used for analysis.

Main Results:

• The 50:50% perceptibility thresholds (PT) were ΔL'=0.74, ΔC'=1.10, and ΔH'=2.40.
• The 50:50% acceptability thresholds (AT) were ΔL'=2.57 and ΔC'=2.70; AT for ΔH' was not computable.
• Statistically significant differences were found among PT values for lightness, chroma, and hue (p ≤ 0.05).

Conclusions:

• Observer sensitivity to gingival color changes differs, with lower sensitivity to hue variations compared to lightness and chroma.
• Specific perceptibility and acceptability thresholds for human gingiva are necessary.
• These gingiva-specific thresholds are essential for evaluating natural gingiva, shade guides, and restorative materials.