title: Color match of two different ceramic systems to selected shades of one shade guide.
abstract: BACKGROUND
  There are no consistent indications given by dental manufacturers on how to layer ceramics to achieve a color match to a shade selected from a dental shade guide. The technique for ceramic layering relies primarily on the skill and experience of ceramists and is not easily predictable.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate, using a clinical spectrophotometer, the ability to color match shades selected with the 3D-Master shade guide using 2 different ceramic systems.
  
  
  METHODS
  Two ceramic systems were selected for this study, the VITA Omega 900 and VITA VM 13. For both systems, shades 2M3, 3M2, 4M2 of the VITA 3D-Master shade guide were selected. Thirty ceramic discs, 15 mm in diameter, were fabricated with different layer thickness ratios of opaque dentin, dentin, and enamel, maintaining a constant overall thickness. A clinical spectrophotometer (VITA Easyshade) was used for color comparison. The measured ΔE values were statistically analyzed with a 3-way ANOVA and the Tukey HSD test (α=.05).
  
  
  RESULTS
  The 3-way ANOVA showed that the ceramic system (P<.001), the selected shade (P<.001), and the layering scheme all significantly influenced the ΔE values (P<.001).
  
  
  CONCLUSIONS
  Both VITA VM 13 and VITA Omega 900 ceramic systems showed a color match with the shades 2M3, 3M2, and 4M2 of the VITA 3D-Master shade guide to be within the limits for clinical acceptability (ΔE≤ 3.3). VM 13 showed a statistically better color match. The layering scheme influenced the definitive color of the restoration.
authors.affiliation: Department of Dental Materials and Fixed Prosthodontics, School of Dentistry, University of Siena, Siena, Italy. gabriele.corciolani@gmail.com
authors.forename: Gabriele
authors.initials: G
authors.lastname: Corciolani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vichi
authors.forename: Chris
authors.initials: C
authors.lastname: Louca
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D003116:Color; D003743:Dental Enamel / Q000033:anatomy & histology; D045662:Dental Etching / Q000379:methods; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003801:Dental Veneers; D003804:Dentin / Q000033:anatomy & histology; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D055620:Optical Phenomena; D017797:Prosthesis Coloring / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D013053:Spectrophotometry; D013499:Surface Properties
chemical_list: D016876:Metal Ceramic Alloys; C110711:vita omega; D003776:Dental Porcelain; D000537:Aluminum Oxide