title: Elemental release from CoCr and NiCr alloys containing palladium.
abstract: OBJECTIVE
  An entirely new subclass of casting alloy composition whereby palladium (∼approximately 25 wt%) is added to traditional base metal alloys such as CoCr and NiCr was recently introduced to the market. The purpose of this study was to evaluate the elemental release of new CoPdCr and NiPdCr alloys and compare them to traditional CoCr and NiCr alloys.
  
  
  METHODS
  Five casting alloys were investigated: CoPdCr-A (NobleCrown NF, The Argen Corporation), CoPdCr-I (Callisto CP+, Ivoclar Vivadent), NiPdCr (NobleCrown, Argen), CoCr (Argeloy N.P. Special, Argen), and NiCr (Argeloy N.P. Star, Argen). Rectangular specimens (n = 6/alloy) were prepared and immersed in a lactic acid/NaCl solution at 37°C for 7 days according to ISO 10271. Solutions were analyzed with ICP-AES to determine elemental release. The concentrations of major ions (cobalt, nickel, palladium, chromium, and molybdenum) were compared using a generalized linear model (p < 0.05). Representative specimens were examined with optical microscopy before and after immersion.
  
  
  RESULTS
  The CoPdCr alloys released a significantly greater amount of respective ions (Co, Cr, Mo, and total ions) compared to the traditional CoCr alloy. No significant differences in elemental release were noted between NiPdCr and NiCr. Optical microscopic examination showed abundant areas of corrosion in the palladium-containing CoCr alloys after immersion, whereas little difference was observed for the other alloys.
  
  
  CONCLUSIONS
  Corrosion resistance measured via elemental release was compromised when CoCr was alloyed with palladium, but this effect was not observed with NiCr.
authors.affiliation: Department of Prosthodontics, Marquette University School of Dentistry, Milwaukee, WI, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Beck
authors.forename: Demetrios M
authors.initials: DM
authors.lastname: Sarantopoulos
authors.forename: Isao
authors.initials: I
authors.lastname: Kawashima
authors.forename: David W
authors.initials: DW
authors.lastname: Berzins
mesh_terms: D000497:Alloys / Q000737:chemistry; D002857:Chromium / Q000032:analysis; D002858:Chromium Alloys / Q000737:chemistry*; D003035:Cobalt / Q000032:analysis / Q000737:chemistry; D003343:Corrosion; D003735:Dental Casting Technique; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D008982:Molybdenum / Q000032:analysis; D009532:Nickel / Q000032:analysis / Q000737:chemistry; D010165:Palladium / Q000032:analysis / Q000737:chemistry; D012996:Solutions; D013054:Spectrophotometry, Atomic
chemical_list: D000497:Alloys; D002858:Chromium Alloys; D012996:Solutions; C099370:palladium-cobalt alloy; D002857:Chromium; C050456:nickel-palladium alloy; D003035:Cobalt; D010165:Palladium; D009532:Nickel; D008982:Molybdenum