title: Inductively coupled plasma-mass spectroscopy measurements of elemental release from 2 high-palladium dental casting alloys into a corrosion testing medium.
abstract: BACKGROUND
  The biocompatibility of high-palladium alloy restorations has been of some concern due to the release of palladium into the oral environment and sensitivity reactions in patients.
  
  
  OBJECTIVE
  This study measured the in vitro elemental release from a Pd-Cu-Ga alloy and a Pd-Ga alloy into a corrosion testing medium.
  
  
  METHODS
  Both alloys were cast into 12-mm-diameter x 1-mm-thick disks, subjected to heat treatment that simulated porcelain firing cycles, polished to a 0.05-mm surface finish, and ultrasonically cleaned in ethanol. Two specimens of each alloy were immersed 3 times (at 7, 70, and 700 hours) in an aqueous lactic acid/NaCl solution used for in vitro corrosion testing and maintained at 37 degrees C. The specimens were removed after each immersion time, and the elemental compositions of the solutions were analyzed with inductively coupled plasma-mass spectroscopy (ICP-MS). Elemental concentrations for the 2 alloys at each immersion time were compared with Student t test (alpha=.05).
  
  
  RESULTS
  No significant differences in palladium release were found for the 7- and 70-hour solutions, but significant differences were found for the 700-hour solutions. Mean concentrations of palladium and gallium in the 700-hour solutions, expressed as mass per unit area of alloy surface, were 97 (Pd) and 46 (Ga) microg/cm(2) for the Pd-Cu-Ga alloy and 5 (Pd) and 18 (Ga) microg/cm(2) for the Pd-Ga alloy.
  
  
  CONCLUSIONS
  Relative proportions of the elements in the solutions were consistent with the release of palladium and breakdown of microstructural phases found in the alloys. The results suggest that there may be a lower risk of adverse biological reactions with the Pd-Ga alloy than with the Pd-Cu-Ga alloy tested.
authors.affiliation: Oral Biology Program, College of Dentistry, The Ohio State University, Columbus, Ohio 43218, USA.
authors.forename: Eser
authors.initials: E
authors.lastname: Tufekci
authors.forename: John C
authors.initials: JC
authors.lastname: Mitchell
authors.forename: John W
authors.initials: JW
authors.lastname: Olesik
authors.forename: William A
authors.initials: WA
authors.lastname: Brantley
authors.forename: Efstratios
authors.initials: E
authors.lastname: Papazoglou
authors.forename: Peter
authors.initials: P
authors.lastname: Monaghan
mesh_terms: D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry; D003300:Copper / Q000032:analysis / Q000737:chemistry; D003343:Corrosion; D003722:Dental Alloys / Q000032:analysis* / Q000737:chemistry; D003734:Dental Casting Investment / Q000032:analysis* / Q000737:chemistry; D003735:Dental Casting Technique; D003775:Dental Polishing; D003902:Detergents / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D005708:Gallium / Q000032:analysis / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D007101:Immersion; D019344:Lactic Acid / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D008422:Materials Testing; D008669:Metallurgy; D010165:Palladium / Q000032:analysis* / Q000737:chemistry; D012965:Sodium Chloride; D013223:Statistics as Topic; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D001672:Biocompatible Materials; D003722:Dental Alloys; D003734:Dental Casting Investment; D003902:Detergents; D019344:Lactic Acid; D000431:Ethanol; D012965:Sodium Chloride; D010165:Palladium; D003300:Copper; D005708:Gallium