title: Effect of substrate shades on the color of ceramic laminate veneers.
abstract: BACKGROUND
  Ceramic laminate veneers are generally fabricated with varying thicknesses ranging from 0.3 to 1 mm, depending on the need to mask discolored teeth or slightly correct the contour of malpositioned teeth. Clinical color reproduction poses a challenge because of color interaction with the underlying substrate, whether tooth structure or esthetic restorative material.
  
  
  OBJECTIVE
  The purpose of this in vitro investigation was to measure the effect of color change resulting from applying 2 shades of ceramic material, translucent (T1) and opaque (O2), to 2 shades of composite resin substrate material, light (A3) and dark (C4), on the overall color of ceramic laminates.
  
  
  METHODS
  Forty disks were fabricated. Twenty disks (15 × 0.5 mm) were cut from pressed ceramic, 10 disks for each shade (translucent and opaque). Additionally, 20 disks (15 × 4.0 mm) were fabricated from light-polymerized composite resin material, 10 disks for each shade (light and dark). The ceramic disks were bonded to the composite resin disks with clear resin cement. The specimen combinations were divided into 4 groups (n=5). Color measurements were done with a colorimeter (Minolta Chroma Meter CR-200b) configured with diffuse illumination/0-degree viewing geometry. Mean CIE lightness (L*), chroma (C*(ab)), and hue angle (h(ab)) values were obtained. A 2-way analysis of variance (ANOVA) was used to compare the means and standard deviations between the different color combinations (α=.05), followed by Tukey's HSD post hoc test for significant interactions.
  
  
  RESULTS
  The 2-way ANOVA showed significant differences (P<.001) in L*, C*(ab), and h(ab) for a change in the composite resin substrate, regardless of the ceramic material shade. There was significant color change from dark to light substrate (P=.044). The mean h(ab) (SD) of dark substrate/opaque veneer was 89.62 (1.5), while the mean h(ab) of light substrate/translucent veneer was 81.23 (1.7).
  
  
  CONCLUSIONS
  Within the limitations of this study, the selected color of a 0.5 mm ceramic laminate veneer was significantly affected by the change in color of the supporting substrate.
authors: Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio 43210-1267, USA. azer.1@osu.edu
authors: Shereen S
authors: SS
authors: Azer
authors: Stephen F
authors: SF
authors: Rosenstiel
authors: Robert R
authors: RR
authors: Seghi
authors: William M
authors: WM
authors: Johnston
mesh_terms: D003116:Color; D003124:Colorimetry; D003188:Composite Resins; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D003801:Dental Veneers; D017797:Prosthesis Coloring / Q000379:methods*
chemical_list: D003188:Composite Resins; D003776:Dental Porcelain