title: Analysis of edge-losses in reflectance measurements of pigmented maxillofacial elastomer.
abstract: Edge-losses occur during reflectance measurements of pigmented maxillofacial elastomer when light is scattered within a sample beyond that part of the surface exposed to the observation system of the optical device. A custom sample-holder is presented which redirects light that would not be measured during conventional reflectance measurement back into the sample. The amount of edge-loss occurring within thin layers of maxillofacial elastomer with tan pigment on black-and-white backings was found to depend on sample thickness, the backing, the beam size used during conventional reflectance measurement, and the optical term bS = (2KS + K2)1/2. Data analysis revealed a significant interaction among these four factors. Additionally, the edge-loss occurring during the tristimulus reflectance measurement of thick samples of maxillofacial elastomer with various concentrations of tan and black pigment was found to be linearly related to bS up to a limiting value, with no additional edge-loss occurring for bS values above this limiting value. Edge-loss is an important consideration during the matching of the optical characteristics of pigmented maxillofacial material to those of human skin.
authors.affiliation: Section of Restorative and Prosthetic Dentistry, College of Dentistry, Ohio State University, Columbus 43210-1241, USA.
authors.forename: W M
authors.initials: WM
authors.lastname: Johnston
authors.forename: N S
authors.initials: NS
authors.lastname: Hesse
authors.forename: B K
authors.initials: BK
authors.lastname: Davis
authors.forename: R R
authors.initials: RR
authors.lastname: Seghi
mesh_terms: D000042:Absorption; D000465:Algorithms; D000704:Analysis of Variance; D001672:Biocompatible Materials / Q000737:chemistry; D003116:Color; D003124:Colorimetry; D006801:Humans; D008027:Light; D016014:Linear Models; D008447:Maxillofacial Prosthesis; D055096:Optical Devices; D055095:Optics and Photonics; D010860:Pigments, Biological / Q000737:chemistry; D011474:Prosthesis Design; D012542:Scattering, Radiation; D012826:Silicone Elastomers / Q000737:chemistry*; D012880:Skin Pigmentation; D013053:Spectrophotometry; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D010860:Pigments, Biological; D012826:Silicone Elastomers