title: Colour stability of aesthetic brackets: ceramic and plastic.
abstract: BACKGROUND
  The colour stability of aesthetic brackets may differ according to their composition, morphology and surface property, which may consequently influence their aesthetic performance.
  
  
  OBJECTIVE
  To assess the colour stability of aesthetic brackets (ceramic and plastic) after simulating aging and staining.
  
  
  METHODS
  Twelve commercially manufactured ceramic brackets and four different plastic brackets were assessed. To determine possible colour change (change of E*(ab)) and the value of the NBS (National Bureau of Standards) unit system, spectrophotometric colour measurements for CIE L*, a* and b* were taken before and after the brackets were aged and stained. Statistical analysis was undertaken using a one-way ANOVA analysis of variance and a Tukey multiple comparison test (alpha = 0.05).
  
  
  RESULTS
  The colour change between the various (ceramic and plastic) materials was not significant (p > 0.05), but still varied significantly (p < 0.001) between the brackets of the same composition or crystalline structure and among commercial brands.
  
  
  CONCLUSIONS
  Colour stability cannot be confirmed simply by knowing the type of material and crystalline composition or structure.
authors.affiliation: Department of Orthodontics, Federal University of Rio de Janeiro (UFRJ) Dental School, Rio de Janeiro, Brazil.
authors.forename: Hibernon Lopes
authors.initials: HL
authors.lastname: Filho
authors.forename: Lúcio Henrique
authors.initials: LH
authors.lastname: Maia
authors.forename: Marcus V
authors.initials: MV
authors.lastname: Araújo
authors.forename: Carlos Nelson
authors.initials: CN
authors.lastname: Eliast
authors.forename: Antônio Carlos O
authors.initials: AC
authors.lastname: Ruellas
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003069:Coffee; D003116:Color; D003124:Colorimetry; D003461:Crystallography; D003764:Dental Materials / Q000737:chemistry*; D004955:Esthetics, Dental; D006801:Humans; D006813:Humidity; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D010969:Plastics / Q000737:chemistry*; D013053:Spectrophotometry; D013499:Surface Properties; D013662:Tea; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D003069:Coffee; D003764:Dental Materials; D010969:Plastics; D013662:Tea