title: Effect of different high-palladium metal-ceramic alloys on the color of opaque porcelain.
abstract: OBJECTIVE
  The purpose of this study was to assess the effect of different high-palladium alloys on the resulting color of opaque porcelain. Three Pd-Cu-Ga alloys, Spartan Plus (S; Williams Dental Co/Division of Ivoclar North America, Amhest, NY), Liberty (B; J.F. Jelenko & Co, Armonk, NY), and Freedom Plus (F; J.F. Jelenko & Co); 4 Pd-Ga alloys, Legacy (L; J.F. Jelenko & Co), IS 85 (I; Williams Dental Co), Protocol (P; Williams Dental Co), and Legacy XT (X; J.F. Jelenko & Co); and a Pd-Ag alloy, Super Star (T; J.F. Jelenko & Co), were examined. The Au-Pd alloy Olympia (O; J.F. Jelenko & Co) served as the control.
  
  
  METHODS
  Three cast 16-mm discs, 1-mm thick, were prepared from each of the alloys. After metallurgically polishing and air-abrading, the specimens were oxidized following the manufacturer's recommendations. Shade B1 opaque porcelain (Vita-Omega; Vident, Baldwin Park, CA) was applied at a final thickness of 0.1 mm using a mold. After 2 opaque porcelain firing cycles, the surfaces were air-abraded. The colors of the specimens were measured using a colorimeter and expressed in Commission International de l'Eclairage (CIE) L*a*b* coordinates. Color differences (delta E) were determined between the control and each experimental group. Analysis of Variance and Tukey-Kramer tests were performed on the delta E data.
  
  
  RESULTS
  The 3 Pd-Cu-Ga alloys showed significantly greater (p < .01) delta E values (S = 2.8 +/- 1.1, B = 3.0 +/- 0.6, and F = 2.1 +/- 0.2) than the remaining 5 experimental groups (L = 0.7 +/- 0.5, I = 0.7 +/- 0.4, P = 0.7 +/- 0.2, X = 0.7 +/- 0.4, and T = 0.7 +/- 0.5). The directions of the significant color changes were relatively equally distributed along the L*, a*, and b* axes, and all delta L*, delta a*, and delta b* values were negative (lower value, more green and blue relative to control O).
  
  
  CONCLUSIONS
  This work suggests that a 0.1-mm-thick layer of opaque porcelain in the Pd-Cu-Ga alloys studied, did not reliably reproduce the color of porcelain.
authors.affiliation: Ohio State University College of Dentistry, Columbus, OH, USA. Minos.Stavridakis@medecine.unige.ch
authors.forename: M M
authors.initials: MM
authors.lastname: Stavridakis
authors.forename: E
authors.initials: E
authors.lastname: Papazoglou
authors.forename: R R
authors.initials: RR
authors.lastname: Seghi
authors.forename: W M
authors.initials: WM
authors.lastname: Johnston
authors.forename: W A
authors.initials: WA
authors.lastname: Brantley
mesh_terms: D020906:Air Abrasion, Dental; D000704:Analysis of Variance; D003116:Color; D003124:Colorimetry; D016001:Confidence Intervals; D003300:Copper / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D013223:Statistics as Topic; D013499:Surface Properties
chemical_list: D003722:Dental Alloys; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D012834:Silver; D010165:Palladium; C049241:olympia; D003300:Copper; D005708:Gallium