title: Dental color standards: shade tab arrangement.
abstract: OBJECTIVE
  The aim of this study was to analyze the shade tab arrangement of two popular dental shade guides, suggest possible improvements, and propose clinical guidelines.
  
  
  METHODS
  Data were recorded using a colorimeter set to standard illuminant source C and CIE L*a*b* system. The manufacturers' shade tab arrangement as well as the possible improvements in the arrangement of shade tabs of Vitapan Classical and Vitapan 3-D Master (Vita Zahnfabrik, Bad Säckingen, Germany) shade guides were examined by regression analysis.
  
  
  RESULTS
  Certain shortcomings in the manufacturers' arrangement of both color standards were observed. The Vitapan 3-D Master arrangement was more consistent, but with a decrease in lightness, tab saturation decreased as well in four of its five groups. When Vitapan Classical and Vitapan 3-D Master tabs were arranged according to deltaE* in relation to the lightest tab, r2 was 0.98 and 0.96, respectively. After dividing the total deltaE* range into four equal segments for the newly established Vitapan Classical guide, r2 was 0.91, 0.95, 0.68, and 0.94, respectively. Corresponding r2 values for Vitapan 3-D Master were 0.96, 0.94, 0.90, 0.94, and 1.0.
  
  
  CONCLUSIONS
  Total color difference in relation to the lightest tab, followed by the tab division into an adequate number of groups, is recommended as a possible and universally applicable mode of tab arrangement in dental color standards.
authors.affiliation: Department of Restorative Dentistry and Biomaterials, University of Texas Health Science Center at Houston, 77030-3402, USA. radeparavina@usa.net
authors.forename: R D
authors.initials: RD
authors.lastname: Paravina
authors.forename: J M
authors.initials: JM
authors.lastname: Powers
authors.forename: R M
authors.initials: RM
authors.lastname: Fay
mesh_terms: D002138:Calibration; D003116:Color / Q000592:standards*; D003124:Colorimetry; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design / Q000295:instrumentation*; D006801:Humans; D008027:Light; D012044:Regression Analysis
chemical_list: D003764:Dental Materials