title: [In vitro evaluation of chromatic stability in new-generation composites].
abstract: BACKGROUND
  Ultraviolet light exposure produces chromatic changes in composites used for esthetic restoration. The aim of the study was to compare the chromatic changes induced by accelerated aging in two composites of new generation: Tetric Ceram and Diamond Crown.
  
  
  METHODS
  Five samples were prepared for each composite, each divided into two pieces, one exposed to accelerated aging obtained by ultraviolet-light exposure for 24 hours, and one maintained in dark. Thereafter, the samples were lighted by a light beam and the percentage of reflected light was assessed. The distribution of the levels of red, green and blue was assessed using a camera connected to a PC with a software for image processing.
  
  
  RESULTS
  For both the composites, the values of the three colors were significantly lower in the samples artificially aged (p<0.0001). The values concerning to the Tetric Ceram were significantly lower than those of Diamond Crown (p<0.0001). The latter showed aging-induced variation significantly smaller than the former.
  
  
  CONCLUSIONS
  Both the composites showed significant chromatic variations after 24 hours artificial aging. Diamond Crown showed significantly better stability.
authors.affiliation: Corso di Laurea in Odontoiatria e Protesi Dentaria, Odontoiatria Restaurativa, Dipartimento di Fisiologia Clinica, Università degli Studi di Torino.
authors.forename: A
authors.initials: A
authors.lastname: De Lillo
authors.forename: S
authors.initials: S
authors.lastname: Lombardo
authors.forename: D
authors.initials: D
authors.lastname: Chiadò Cutin
authors.forename: F
authors.initials: F
authors.lastname: Pirri
authors.forename: S
authors.initials: S
authors.lastname: Carossa
mesh_terms: D001672:Biocompatible Materials / Q000528:radiation effects*; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000528:radiation effects*; D007091:Image Processing, Computer-Assisted; D008422:Materials Testing; D010777:Photochemistry; D013053:Spectrophotometry; D013997:Time Factors; D014867:Water
chemical_list: D001672:Biocompatible Materials; D003188:Composite Resins; C472423:Diamond Crown; C121818:Tetric ceram; D014867:Water