ASTM_E_2466_-_13.pdf

Designation:E246613Standard Test Method forColorimetry of Teeth Using Digital Still Camera Technology1This standard is issued under the fixed designation E2466;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONTooth color is an important parameter used to ascertain certain medical and esthetic information.CIE colorimetric values for the teeth are derived from the native RGB signals generated by a digitalstill camera,DSC,by broadband measurement of the reflectance of teeth.The illumination angle is 45degrees and CIELAB colorimetric coordinates are computed using equations contained in PracticeE308.This test method,E2466,specifies the procedure used for the measurement of tooth colorin-vivo and in-vitro with illumination at 45 degrees relative to the sample plane which is also thenormal of the mouth,under an approximate equal energy spectrum.This test method is appropriate foranterior and posterior teeth.1.Scope1.1 This test method covers the procedure,instrumentalrequirements,standardization procedures,material standards,measurement procedures,and parameters necessary to makeprecise measurements of in-vivo tooth color and tooth white-ness.In particular it is meant to measure the color of teeth inselected human subjects.1.2 Digital images are used to evaluate tooth color of bothposterior and anterior dentition(teeth).All other non-relevantparts,such as gums,spaces,etc.,must be separated from themeasurement and the analysis.All localized discoloration;suchas stains,inclusions,etc.,may be separated from the measure-ment and the analysis.1.3 The broadband reflectance factors of teeth are measured.The colorimetric measurement is performed with a digital stillcamera while using an illuminator(s)that provides controlledillumination on the teeth.The measured data from a digitalimage are captured using a DSC.This test method is particu-larly useful for the gamut of tooth color which is:1.3.1 CIE L*from 55 to 95,1.3.2 CIE a*from 3 to 12,1.3.3 CIE b*from 8 to 25 units.1.4 The wavelengths for this test method include thatportion of the visible spectrum from 400 to 700 nm.1.5 Data acquired using this test method is for comparativepurposes used during clinical trials or other types of research.1.6 This test method is designed to encompass natural teeth,artificial teeth,restorations,and shade guides.NOTE1This procedure may not be applicable for all types of dentalwork.1.7 The apparatus,measurement procedure,data analysistechnique are generic,so that a specific apparatus,measure-ment procedure,or data analysis technique may not be ex-cluded.1.8 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.9 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesE179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Propertiesof Materials1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.06 on ImageBased Color Measurement.Current edition approved Jan.1,2013.Published January 2013.Originallyapproved in 2006.Last previous edition approved in 2011 as E2466 06(2011).DOI:10.1520/E2466-13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 E284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE313 Practice for Calculating Yellowness and WhitenessIndices from Instrumentally Measured Color CoordinatesE1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple MeasurementsE1767 Practice for Specifying the Geometries of Observa-tion and Measurement to Characterize the Appearance ofMaterials2.2 ISO Publications:3ISO 17321-1 Colour characterization of digital still cameras(DSCs)Part 1:Stimuli,metrology,and test procedures2.3 ISCC Publications:4Technical Report 2003-1 Guide to Material Standards andTheir Use in Color Measurement3.Terminology3.1 Terms and definitions in Terminology E284 are appli-cable to this test method.3.2 Definitions:3.2.1 Terms included i