title: Influence of resin cement shade on the color and translucency of ceramic veneers.
abstract: OBJECTIVE
  This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates.
  
  
  METHODS
  One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick) under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE) of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B) and white (W) background readings was used for TP analysis, while chroma was calculated by the formula C*ab=(a*2+b*2)½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test.
  
  
  RESULTS
  HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC.
  
  
  CONCLUSIONS
  Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable.
authors.affiliation: - Universidade de Guarulhos, Departamento de Odontologia Restauradora, Guarulhos, SP, Brasil.
authors.forename: Daiana Kelly Lopes
authors.initials: DK
authors.lastname: Hernandes
authors.affiliation: - Universidade Estadual de Ponta Grossa, Departamento de Dentística, Ponta Grossa, PR, Brasil.
authors.forename: Cesar Augusto Galvão
authors.initials: CA
authors.lastname: Arrais
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia, Departamento de Materiais Odontológicos, São Paulo, SP, Brasil.
authors.forename: Erick de
authors.initials: Ed
authors.lastname: Lima
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia, Departamento de Materiais Odontológicos, São Paulo, SP, Brasil.
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
authors.affiliation: - Universidade de Guarulhos, Departamento de Odontologia Restauradora, Guarulhos, SP, Brasil.
authors.forename: José Augusto
authors.initials: JA
authors.lastname: Rodrigues
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D002516:Ceramics / Q000737:chemistry*; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D003776:Dental Porcelain / Q000737:chemistry; D003801:Dental Veneers; D008422:Materials Testing; D011140:Polyurethanes / Q000737:chemistry*; D017797:Prosthesis Coloring / Q000379:methods*; D012016:Reference Values; D019279:Resin Cements / Q000737:chemistry*; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D011140:Polyurethanes; D019279:Resin Cements; C513703:Vivadent; C493120:lithia disilicate; D003776:Dental Porcelain; C103502:Variolink