title: Release of metal ions from fixed orthodontic appliance: an in vitro study in continuous flow system.
abstract: OBJECTIVE
  To evaluate the release of metal ions from fixed orthodontic appliances.
  
  
  METHODS
  A new system for in vitro testing of dental materials was constructed and consisted of a thermostatic glass reactor that enabled immersion of the studied material. Experimental conditions reflected the human oral cavity, with a temperature of 37°C and a saliva flow rate of 0.5mL/min. The simulated fixed orthodontic appliance made of stainless steel was evaluated. Sampling was performed at several time points during the 28-day study, and the metal ion concentration was determined by inductively coupled plasma optical emission spectrometry.
  
  
  RESULTS
  The total mass of released metal ions from the appliance during 4 weeks of the experiment was as follows nickel 18.7 μg, chromium 5.47 μg, copper 31.3 μg.
  
  
  CONCLUSIONS
  The estimated doses of nickel, chromium, and copper determined by extrapolation of experimental data released during the treatment period were far below the toxic dose to humans. This shows that orthodontic treatment might not be a significant source of exposure to these metal ions.
authors.affiliation: a  Assistant Professor, Department of Dentofacial Orthopedics and Orthodontics, Wroclaw Medical University, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Mikulewicz
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Chojnacka
authors.forename: Paulina
authors.initials: P
authors.lastname: Wołowiec
mesh_terms: D002857:Chromium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D020724:Elastomers / Q000737:chemistry; D004867:Equipment Design; D006801:Humans; D007700:Kinetics; D008422:Materials Testing / Q000295:instrumentation; D008670:Metals / Q000737:chemistry; D009532:Nickel / Q000737:chemistry; D009967:Orthodontic Appliances; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012464:Saliva, Artificial / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D013193:Stainless Steel / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
chemical_list: D003722:Dental Alloys; D020724:Elastomers; D008670:Metals; D012464:Saliva, Artificial; D002857:Chromium; D013193:Stainless Steel; D003300:Copper; D009532:Nickel; D012825:Silicon