title: Elements released from dental casting alloys and their cytotoxic effects.
abstract: OBJECTIVE
  This in vitro study investigated the element release from seven commercially available dental casting alloys and tested their cytotoxic effects.
  
  
  METHODS
  The casting alloys tested were one high-noble alloy (Bioherador N) and six base-metal alloys, including four Ni-Cr alloys (Remanium CS, Heranium NA, Wiron 99, CB Soft), one Co-Cr alloy (Wirobond C), and one Cu-based alloy (Thermobond). Ten specimens from each alloy were prepared in the form of disks, and each of the seven dental casting alloys (10 disks per group) were conditioned in distilled water at 37 degrees C for either 72 or 168 hours. The conditioning media were analyzed for element release, and the cytotoxic effects were assessed on Balb C fibroblasts using MTT assay.
  
  
  RESULTS
  Element release was greater at 168 hours of conditioning than at 72 hours. The extract from the high-noble alloy showed the least amount of element release (only Zn), with no cytotoxic effects. The greatest amount of element release was detected in the Cu-based alloy Thermobond and the Ni-Cr alloy CB Soft; their extracts were significantly more toxic than all the other alloy extracts. The cytotoxic effects of the other Ni-Cr alloy extracts were not statistically significantly different from the high-noble alloy extract. However, the Co-Cr alloy (Wirobond C) extract was significantly more cytotoxic than the high-noble alloy extract.
  
  
  CONCLUSIONS
  Element release from casting alloys is proportional to the conditioning time. The content of Cr and Mo in the alloy protects the alloy from dissolution, while the Cu content makes it more susceptible to corrosion and dissolution, rendering it more cytotoxic.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan. hiyasat@just.edu.jo
authors.forename: Ahmad S
authors.initials: AS
authors.lastname: al-Hiyasat
authors.forename: Omar M
authors.initials: OM
authors.lastname: Bashabsheh
authors.forename: Homa
authors.initials: H
authors.lastname: Darmani
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D003035:Cobalt / Q000633:toxicity; D003300:Copper / Q000633:toxicity; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry* / Q000633:toxicity*; D004577:Electron Probe Microanalysis; D005347:Fibroblasts / Q000187:drug effects*; D008422:Materials Testing; D051379:Mice; D008807:Mice, Inbred BALB C; D008982:Molybdenum / Q000633:toxicity; D009532:Nickel / Q000633:toxicity; D013997:Time Factors; D015032:Zinc / Q000633:toxicity
chemical_list: D003722:Dental Alloys; D003035:Cobalt; D003300:Copper; D009532:Nickel; D008982:Molybdenum; D015032:Zinc