title: Effect of esthetic core shades on the final color of IPS Empress all-ceramic crowns.
abstract: BACKGROUND
  Clinically relevant assessment of all-ceramic crowns supported by esthetic composite resin foundations has not been evaluated with regard to color reproducibility.
  
  
  OBJECTIVE
  This in vitro study quantitatively evaluated the influence of different shades of composite resin foundations and resin cement on the final color of a leucite-reinforced all-ceramic material.
  
  
  METHODS
  A total of 128 disks were fabricated; 64 (20 x 1 mm) were made of all-ceramic material (IPS Empress) and 64 (20 x 4 mm) of 4 different shades composite resin (Tetric Ceram). The ceramic and composite resin disks were luted using 2 shades (A3 and Transparent) of resin cement (Variolink II). Color was measured using a colorimeter configured with a diffuse illumination/0-degree viewing geometry, and Commission Internationale de l'Eclairage (CIE) L( *)a( *)b( *) values were directly calculated. Descriptive statistical analysis was performed, and color differences (DeltaE) for the average L( *), a( *) and b( *) color parameters were calculated. Repeated measures analysis of variance (ANOVA) was used to compare mean values and SDs between the different color combinations (alpha=.05).
  
  
  RESULTS
  The CIE L( *)a( *)b( *) color coordinate values showed no significant differences for variation in color parameters due to the effect of the different composite resin shades (P=.24) or cement shades (P=.12). The mean color difference (DeltaE) value between the groups was 0.8.
  
  
  CONCLUSIONS
  Within the limitations of this study, the use of different shades for composite resin cores and resin cements presented no statistically significant effect on the final color of IPS Empress all-ceramic material.
authors.affiliation: Section of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, Ohio 3218-2357, USA. azer.1@osu.edu <azer.1@osu.edu>
authors.forename: Shereen S
authors.initials: SS
authors.lastname: Azer
authors.forename: Ghada M
authors.initials: GM
authors.lastname: Ayash
authors.forename: William M
authors.initials: WM
authors.lastname: Johnston
authors.forename: Moustafa F
authors.initials: MF
authors.lastname: Khalil
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Rosenstiel
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry*; D000704:Analysis of Variance; D003116:Color; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry; D017797:Prosthesis Coloring / Q000379:methods*; D019279:Resin Cements / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D000538:Aluminum Silicates; C029012:Composite Dental Resin; D003188:Composite Resins; D003764:Dental Materials; C075815:IPS-Empress ceramic; D011140:Polyurethanes; D019279:Resin Cements; D003776:Dental Porcelain