title: [Study on relationship of different thickness and opaquing capacity of various opaques].
abstract: OBJECTIVE
  To evaluate the relation between different opaque thickness and color difference.
  
  
  METHODS
  Model made of the thin plastic paper was used to control the ceramic thickness. The data of chromaticity was measured by TC-PIIG auto color difference meter and its results were processed by computer.
  
  
  RESULTS
  There are two thickness values which can be considered as ideal range of opaque thickness for color opaquing: one is the values of ceramic thickness which is based on the color difference values of the infinite chromaticity thickness (ICT) and the other is the values of ceramic thickness which is depended on the color difference values which is 1.5 compared with ICT. The ideal range for VITA is (0.207-0.152) mm, SHOFO is (0.190-0.160) mm, CARAT is (0.140-0.074) mm and EXCELCO is (0.169-0.144) mm.
  
  
  CONCLUSIONS
  There is a relationship of non linear direct ratio between opaque thickness and its shadow capacity. However, no more increase of color difference values in respect to the thickness was found when the ceramic thickness reach a certain value. Different ceramic porcelain needs different ideal range of thickness.
authors.affiliation: College of Stomatology, West China University of Medical Sciences, Chengdu 610041.
authors.forename: Y
authors.initials: Y
authors.lastname: Luo
authors.forename: Y
authors.initials: Y
authors.lastname: Chao
mesh_terms: D002516:Ceramics / Q000592:standards; D003116:Color / Q000592:standards; D003764:Dental Materials / Q000032:analysis / Q000592:standards*; D003776:Dental Porcelain / Q000592:standards*; D008422:Materials Testing / Q000379:methods; D016876:Metal Ceramic Alloys / Q000592:standards; D017797:Prosthesis Coloring / Q000592:standards
chemical_list: D003764:Dental Materials; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain