Translucency estimation for thick pigmented maxillofacial elastomer

Human skin is multilayered and inhomogeneous and has a partially translucent structure. Since it is not straightforward to quantify the translucency for human skin as it is for translucent materials at a certain thickness, a laser light-diffusing method was developed to quantitatively approximate translucency of translucent pigmented maxillofacial materials, using a technique that would be applicable to human skin. A developed method of laser light diffusing area (LLDA) and the method of color difference due to edge loss (CDEL) were compared in accuracy of translucency estimations of thick pigmented maxillofacial elastomeric material.

Thick specimens of 19 different shades of skin-colored maxillofacial elastomer (MFE) were made with a silicone elastomer and four commercially available pigments (tan, red, yellow and black). Translucency parameter (TP) values at a thickness of 1.5mm on ideal black and white backings for each shade based on the CIELAB and CIE2000 color difference formulas were previously calculated, and were predicted by the regressions of TP onto the LLDA and CDEL measurements.

Both the LLDA and CDEL methods provided reasonably accurate (adjusted R(2) ≥ 0.919) estimations of TP, and no significant differences were found in the error variances of the regressions.

The laser light diffusing method appears to be highly reliable for the estimation of translucency of maxillofacial elastomer, and the relationship of translucency to LLDA may be used to estimate the apparent translucency of any thick translucent material within the range of translucency studied. The laser light diffusing method as a non-contact and non-destructive method may be applied to quantitatively estimate the translucency of human skin and prosthetic elastomers, and further be incorporated into appearance matching of maxillofacial prosthesis to human skin.