title: Colour stability of provisional crown and bridge restoration materials.
abstract: OBJECTIVE
  In an in vitro study to determine the colour stability of provisional restoration materials, the PMMA synthetics Trimm and Cronsin and the bis-acrylic composites Protemp Garant, Protemp Garant NF, Protemp II and Provipont DC were investigated.
  
  
  METHODS
  The colour changes of the cylindrical untreated samples were measured in comparison with samples after 24 and 72 hours of artificial ageing in a Suntest CPS+ UV ageing device using the Minolta CM 3500d spectrophotometer according to the CIE-L*a*b* system.
  
  
  RESULTS
  Trimm (light), Cronsin (brown, yellow and universal), Provipont DC (yellow) and Protemp Garant NF (extra light) displayed the greatest discoloration with values > or = 4-21 delta E, where discoloration toward yellow could be discerned. The remaining materials showed lower luminance reflectance values of < or = 1-4 delta E, and therefore greater colour stability.
  
  
  CONCLUSIONS
  Because of their colour stability the materials Cronsin (grey), Protemp Garant (yellow), Protemp II (light), Protemp Garant NF (yellow, light and extra light) could also be used as long-term interim prosthetics.
authors.affiliation: Department of Prosthetic Dentistry, University Clinics, Regensburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Lang
authors.forename: M
authors.initials: M
authors.lastname: Rosentritt
authors.forename: A
authors.initials: A
authors.lastname: Leibrock
authors.forename: M
authors.initials: M
authors.lastname: Behr
authors.forename: G
authors.initials: G
authors.lastname: Handel
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003442:Crowns; D017267:Dental Prosthesis Design / Q000592:standards*; D003830:Denture, Partial, Fixed; D006801:Humans; D008422:Materials Testing; D019904:Polymethyl Methacrylate / Q000737:chemistry; D017797:Prosthesis Coloring / Q000592:standards*; D018709:Statistics, Nonparametric
chemical_list: D017438:Bisphenol A-Glycidyl Methacrylate; D019904:Polymethyl Methacrylate