title: Optical influence of the type of illuminant, substrates and thickness of ceramic materials.
abstract: OBJECTIVE
  The present study is an instrumental evaluation of the optical influence of the type of illuminant, substrate and different thickness on the color of dental ceramics.
  
  
  METHODS
  Thirty ceramic disks were prepared from IPS-Empress and IPS-Empress2 in three different thicknesses (1.5, 2.0 and 2.5mm). Disks made of composite resin; silver-palladium alloy and gold were used as substrates. The disks with a 1.5mm thickness were placed on a neutral gray photographic paper and measured with a spectrophotometer under three illuminants: daylight (D65), incandescent light (A) and fluorescent light (F6). All ceramic disks were combined with the substrate disks and a spectrophotometer was used to measure the coordinates of lightness (L*) and chromaticity (a* and b*). Two-way ANOVA (p<0.05) was used to analyze the combinations of ceramics, substrates and illuminants tested considering the coordinates of lightness (L*) and chromaticity (a* and b*), and also differences of color (DeltaE), lightness (DeltaL*), chromaticity values (Deltaa* and Deltab*).
  
  
  RESULTS
  For the illuminants tested, the results present significant differences for coordinates of chromaticity a* and b*, suggesting a metamerism effect. In combination with the substrates, the results present statistical differences in all the tested conditions, especially where there is no ceramic substructure.
  
  
  CONCLUSIONS
  The presence of discolored tooth remnants or metallic posts and cores can interfere with the desired aesthetic result, based on the selection of color aided by a single luminous source. Thus, the substrate color effect, thickness of the ceramic materials and type of illuminant are important factors to be considered during the clinical application of the ceramic systems.
authors.affiliation: Department of Stomatology, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil. claudiamvolpato@hotmail.com
authors.forename: Cláudia Angela Maziero
authors.initials: CA
authors.lastname: Volpato
authors.forename: Sylvio
authors.initials: S
authors.lastname: Monteiro
authors.forename: Mauro Caldeira
authors.initials: MC
authors.lastname: de Andrada
authors.forename: Márcio Celso
authors.initials: MC
authors.lastname: Fredel
authors.forename: Carlos Otávio
authors.initials: CO
authors.lastname: Petter
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008027:Light; D008029:Lighting / Q000145:classification; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D010165:Palladium / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013053:Spectrophotometry; D013472:Sunlight; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; D003722:Dental Alloys; D003764:Dental Materials; C118557:Empress 2; C474035:Filtek Supreme; D006047:Gold Alloys; C075815:IPS-Empress ceramic; D018020:Lithium Compounds; C493120:lithia disilicate; D003776:Dental Porcelain; C078519:leucite; D012834:Silver; D010165:Palladium