title: Variation in instrument-based color coordinates of esthetic restorative materials by measurement method-A review.
abstract: OBJECTIVE
  Optical properties of an object are determined visually or instrumentally. Although instrumental measurement provides objective and quantitative color coordinates, these values vary by the measurement method such as specimen and background conditions, instrument settings and illuminant. The objective of this study was to review the influence of the measurement method on the instrumental color coordinates of esthetic dental restorative materials.
  
  
  METHODS
  Published reports on the measurement method dependent color variations of esthetic restorative materials were reviewed.
  
  
  RESULTS
  Surface roughness influences the color coordinates differently by the surface roughness range and the measurement geometry. Specimen thickness and the kind of illuminant influence the color coordinates, and the influence of background varied by specimen thickness. Therefore, the specular component excluded (SCE) geometry that reflects the surface condition of specimens is suggested as the correct measurement geometry. Surface roughness, thickness and layering of specimens, and the kind of illuminant should be stipulated in each measurement. There should be a standard for the color and gloss of the background.
  
  
  CONCLUSIONS
  Variables in instrumental color measurements should be stipulated to obtain consistent and comparable color coordinates, and a general guideline for instrumental color measurement of dental materials should be established.
authors.affiliation: R&D Department, Denforus Co., Seoul, Republic of Korea. ykleedm@gmail.com
authors.forename: Yong-Keun
authors.initials: YK
authors.lastname: Lee
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.forename: Seung-Hun
authors.initials: SH
authors.lastname: Lee
authors.forename: Moon-Sang
authors.initials: MS
authors.lastname: Cho
authors.forename: Chi-Youn
authors.initials: CY
authors.lastname: Lee
authors.forename: Ho-Nam
authors.initials: HN
authors.lastname: Lim
mesh_terms: D003116:Color; D003124:Colorimetry / Q000295:instrumentation*; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D004955:Esthetics, Dental; D006801:Humans; D008027:Light; D055620:Optical Phenomena; D013499:Surface Properties
chemical_list: D003764:Dental Materials