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.
Conclusion: 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.