Coverage error of commercial skin pigments as compared to human facial skin tones

It is unknown if present-day pigments used for intrinsic colouration of maxillofacial prostheses are representative of human facial skin tones. This study's purpose was to measure L*a*b* values of pigmented elastomers coloured by eleven skin tone pigments and determine coverage error (CE) when the pigments were compared to human facial lip and nose colour data.

11 skin tone pigments were combined at 0.1%, 1% and 10% by weight with A-2186 elastomer (n=3). L*a*b* values were measured with a spectrophotometer and group means were used to calculate ΔE* colour differences with each L*a*b* value obtained for human nose and lip. Pigmented elastomer CEs were calculated for nose and lip. Results were compared to CEs for proposed shade guide colours obtained from clustering analyses of facial skin colours.

L* values of pigmented elastomers generally were higher than those measured for nose and lip, whereas a* values were lower. CEs for pigmented elastomers were higher than those obtained from the proposed shade guide obtained from clustered skin measurements.

Overall, the current commercial elastomers appeared to be too white and not red enough to adequately match the skin tones of the subject population. Adjustments must be made to the existing pigmenting system in order to adequately match the skin colours of the study population.

The creation of a shade guide and a collection of intrinsic pigments representing the realm of human facial skin colours would greatly decrease the time a patient must sit while the clinician is obtaining an acceptable colour match for the silicone to be used for processing the final prosthesis, thereby increasing both patient satisfaction and clinician productivity.