title: Difference between selected and obtained shade for metal-ceramic crown systems.
abstract: OBJECTIVE
  This study evaluated shade differences between selected shades (2 M 2, 3D Master system, Vitazahnfabrik) and obtained shades of crowns made with a gold electroforming metal-ceramic system (Gramm Technik GmbH) veneered with porcelain and compared those crowns with crowns made with In-Ceram alumina blocks (Vitazahnfabrik) in a CEREC 3D machine (Sirona Dental Systems LLC) and with a porcelain-fused-to-metal system (Classic IV gold alloy, Jensen Dental).
  
  
  METHODS
  Ten crown restorations were constructed for each group (gold electroforming, In-Ceram alumina and porcelain-fused-to-metal) following the manufacturers' directions. Shade difference between a selected shade (2 M 2) and the obtained shades was measured using an intraoral spectrophotometer (Easyshade). Data was statistically analyzed.
  
  
  RESULTS
  Shade differences for the three groups were between 1.21-1.56, with the gold electroformed crowns having the lowest mean and the porcelain-fused-to-metal having the highest mean. Statistical analysis with ANOVA revealed a significant difference among the three systems (p < .0001). Further statistical analysis with post hoc Tukey's test revealed a significant difference in means between the porcelain-fused-to-metal group and the other two groups (p < 0.021). No significant difference was detected between the means of the gold electroformed crowns and the In-Ceram alumina crowns (p = 0.981).
  
  
  CONCLUSIONS
  Veneered gold electroformed crowns and In-Ceram crowns produced shade matching significantly better than that obtained with porcelain-fused-to-metal crowns.
authors.affiliation: Department of Fixed Prosthodontics, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt. hananakomar@yahoo.com
authors.forename: Hanan
authors.initials: H
authors.lastname: Omar
authors.forename: Osama
authors.initials: O
authors.lastname: Atta
authors.forename: Omar
authors.initials: O
authors.lastname: El-Mowafy
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003116:Color; D003442:Crowns; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003801:Dental Veneers; D004563:Electrochemistry; D006047:Gold Alloys / Q000737:chemistry*; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D017797:Prosthesis Coloring; D013053:Spectrophotometry
chemical_list: D006047:Gold Alloys; C483026:In-Ceram Alumina; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; C074543:Cerec