title: [An evaluation on corrosion resistance of magnetic retainers].
abstract: OBJECTIVE
  The present study was to explore the corrosion resistance of three kinds of magnetic retainers which named neodymium-iron-boron magnet and encapsulated in stainless steel.
  
  
  METHODS
  Three kinds of magnetic retainers were exposed for 6 months to artificial saliva thermostated at 36.5 degrees C. This study included a electrochemical test as polarization curves and a chemical test as immersion test.
  
  
  RESULTS
  In the electrochemical test, current density of the national keeper was 7.015 microA/cm2 and magnet was 0.119 microA/cm2. In the chemical test, corrosion rate of national keeper was 3.67 x 10(-5) mg/cm2.h and magnet was 1.77 x 10(-5) mg/cm2.h. The corrosion resistance of the national magnetic retainer had little difference with the imported ones.
  
  
  CONCLUSIONS
  Transient exposure of stainless steel to artificial saliva environment is likely to significantly increase elemental release. It would affect the useful life span of magnets.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Shanghai Second Medical University, Shanghai 200011, China.
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: B
authors.initials: B
authors.lastname: Hu
authors.forename: Y
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D017268:Dental Prosthesis Retention; D005069:Evaluation Studies as Topic; D008280:Magnetics; D018704:Orthodontic Retainers
chemical_list: D003722:Dental Alloys