title: Effects of environment on the release of Ni, Cr, Fe, and Co from new and recast Ni-Cr alloy.
abstract: BACKGROUND
  The addition of previously cast alloy to new alloy for economic reasons may increase the release of elements.
  
  
  OBJECTIVE
  The purpose of this study was to analyze the effects of the immersion period, immersion media, and addition of previously cast alloy to new alloy on the release of elements.
  
  
  METHODS
  Disk-shaped specimens were prepared from a Ni-Cr alloy (Ni: 61 wt%, Cr: 26 wt%, Mo: 11 wt%, Si: 1.5 wt%, Fe, Ce, Al, and Co <1 wt%) (Remanium CS; Dentaurum) with new alloy (group N) and 50% new/50% recast alloy (group R). After the immersion of the specimens in both NaCl (pH 4) and artificial saliva (pH 6.7) for 3, 7, 14, 30, and 60 days, the release of ions was determined by using atomic absorption spectrometry. Data were analyzed with a 3-way ANOVA (α=.001).
  
  
  RESULTS
  The release of Ni was significantly affected by the immersion period, of Ni and Cr by the alloy and media (P<.01), and of Fe by the alloy (P<.01). Ion release from the recast alloy in artificial saliva was 109.71 for Ni, 6.49 for Cr, 223.22 for Fe, and 29.90 μg/L for Co. The release of Co in NaCl was below the detection limit in both groups.
  
  
  CONCLUSIONS
  The release of Ni in NaCl and artificial saliva increased with the length of the immersion period in both groups. The release of Cr and Fe was higher in artificial saliva than in NaCl in group R, regardless of the immersion period. The release of Co in NaCl was below the detection limit in both groups.
authors.affiliation: Assistant Professor, School of Health Services, Dental Prosthetics Technology, Hacettepe University, Ankara, Turkey. Electronic address: poyar73@gmail.com.
authors.forename: Perihan
authors.initials: P
authors.lastname: Oyar
authors.affiliation: Professor, Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey.
authors.forename: Gülşen
authors.initials: G
authors.lastname: Can
authors.affiliation: Professor, Department of Chemistry, Faculty of Science, Ankara University, Tandogan Campus, Tandogan, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Atakol
mesh_terms: D002857:Chromium / Q000737:chemistry*; D002858:Chromium Alloys / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D003734:Dental Casting Investment / Q000737:chemistry*; D003775:Dental Polishing / Q000379:methods; D004058:Diffusion; D017743:Equipment Reuse; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D007501:Iron / Q000737:chemistry*; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D013997:Time Factors
chemical_list: D002858:Chromium Alloys; D003734:Dental Casting Investment; D012464:Saliva, Artificial; D002857:Chromium; D003035:Cobalt; D012965:Sodium Chloride; D009532:Nickel; D007501:Iron