title: Relevant optical properties for direct restorative materials.
abstract: OBJECTIVE
  To evaluate relevant optical properties of esthetic direct restorative materials focusing on whitened and translucent shades.
  
  
  METHODS
  Enamel (E), body (B), dentin (D), translucent (T) and whitened (Wh) shades for E (WhE) and B (WhB) from a restorative system (Filtek Supreme XTE, 3M ESPE) were evaluated. Samples (1 mm thick) were prepared. Spectral reflectance (R%) and color coordinates (L*, a*, b*, C* and h°) were measured against black and white backgrounds, using a spectroradiometer, in a viewing booth, with CIE D65 illuminant and d/0° geometry. Scattering (S) and absorption (K) coefficients and transmittance (T%) were calculated using Kubelka-Munk's equations. Translucency (TP) and opalescence (OP) parameters and whiteness index (W*) were obtained from differences of CIELAB color coordinates. R%, S, K and T% curves from all shades were compared using VAF (Variance Accounting For) coefficient with Cauchy-Schwarz inequality. Color coordinates and optical parameters were statistically analyzed using one-way ANOVA, Tukey's test with Bonferroni correction (α=0.0007).
  
  
  RESULTS
  Spectral behavior of R% and S were different for T shades. In addition, T shades showed the lowest R%, S and K values, as well as the highest T%, TP an OP values. In most cases, WhB shades showed different color and optical properties (including TP and W*) than their corresponding B shades. WhE shades showed similar mean W* values and higher mean T% and TP values than E shades.
  
  
  CONCLUSIONS
  When using whitened or translucent composites, the final color is influenced not only by the intraoral background but also by the color and optical properties of multilayers used in the esthetic restoration.
authors.affiliation: Post-Graduate Program in Dentistry, Dental School, University of Passo Fundo, Campus I, BR 285, Km 171, 99001-970, Passo Fundo, RS, Brazil; Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, s/n 18071, Granada, Spain.
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Pecho
authors.affiliation: Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, s/n 18071, Granada, Spain.
authors.forename: Razvan
authors.initials: R
authors.lastname: Ghinea
authors.affiliation: Department of Stomatology, School of Dentistry, University of Granada, Campus de Cartuja, s/n 18071, Granada, Spain.
authors.forename: Erika A Navarro
authors.initials: EA
authors.lastname: do Amaral
authors.affiliation: Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, s/n 18071, Granada, Spain.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Cardona
authors.affiliation: Post-Graduate Program in Dentistry, Dental School, University of Passo Fundo, Campus I, BR 285, Km 171, 99001-970, Passo Fundo, RS, Brazil. Electronic address: dbona@upf.br.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Della Bona
authors.affiliation: Department of Optics, Faculty of Science, University of Granada, Campus Fuente Nueva, Edificio Mecenas, s/n 18071, Granada, Spain.
authors.forename: María M
authors.initials: MM
authors.lastname: Pérez
mesh_terms: D003116:Color; D003188:Composite Resins; D003743:Dental Enamel; D003764:Dental Materials; D003804:Dentin; D006801:Humans
chemical_list: D003188:Composite Resins; D003764:Dental Materials
keywords: Absorption coefficient; Color; Dental composites; Opalescence; Scattering coefficient; Translucency