title: Effects of 5 manipulative variables on the color of ceramics used for computer-generated restorations.
abstract: OBJECTIVE
  Monochromatic ceramic blocks used for computer-generated posterior restorations require color modification to achieve acceptable shade matches. However, it is not known whether manipulative variables affect the final color of these restorations. This study aimed to determine the effects of ceramic type, thickness, extrinsic colorants, glazing, and luting agent on the final color of monochromatic computer-generated ceramics.
  
  
  METHODS
  One hundred forty-five ceramic specimens (12 mm x 10 mm) with different thicknesses were machined from monochromatic ProCAD ceramics (shades 100, 200, and 300; Ivoclar Vivadent) and Vita ceramics (shades A3.5 and 3M2; Vita). The influence of thickness on color was determined on ProCAD and Vita specimens with thicknesses of 1.0, 1.2, 1.5, 2.0, and 10.0 mm, and the influence of extrinsic colorants, glazing, and luting agent was determined on ProCAD and Vita ceramics of 1.5-mm thickness. Panavia F TC (Kuraray) was used to create a luting-agent backing of 100-microm thickness. CIELAB color coordinates (L*a*b*) were measured using a spectrophotometer, and color differences (DeltaE) between the specimens were calculated. The criterion for color difference was considered to be 1.5 DeltaE units. The data were statistically evaluated with ANOVA and the 2-tailed t test with a level of significance of 5%.
  
  
  RESULTS
  All 5 variables demonstrated significant differences for both ProCAD and Vita ceramics (P = .000). The DeltaE values were larger than 1.5 units.
  
  
  CONCLUSIONS
  Thickness and type of ceramic as well as extrinsic colorants, glazing, and a luting agent affect the color coordinates of monochromatic industrial ceramic.
authors.affiliation: Department of Oral Function and Prosthetic Dentistry, Academy Center for Dentistry Amsterdam, The Netherlands. h.denissen@acta.nl
authors.forename: Harry
authors.initials: H
authors.lastname: Denissen
authors.forename: Alma
authors.initials: A
authors.lastname: Dozic
authors.forename: Marinus
authors.initials: M
authors.lastname: van Waas
authors.forename: Albert
authors.initials: A
authors.lastname: Feilzer
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods; D017076:Computer-Aided Design; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000379:methods*; D017797:Prosthesis Coloring / Q000379:methods*; D013053:Spectrophotometry / Q000379:methods
chemical_list: D003764:Dental Materials