Abstract:

Objective　The aim of this article was to discover the corrosion resistance of magnetic attachments, which were encapsulated in stainless steel, when pHvalue of artificial saliva was lower than normal.Methods　Three kinds of magnetic retainers were exposed for 6 months to artificial saliva with pH ranging from 5·6 to 7·0, thermostated at 36·5℃. This study in- cluded electrochemical test as polarization curves, chemical test as immersion test and SEMto analyze the corrosion behavior of the materials.Results　Fe3+ions in stainless steel released more than ten times in an environment pH5·6 than pH7·0. The higher concentration of H+, the more elemental release. That pH value of artificial saliva reduced may affect the corrosion speed. The magnetic retainers were not resistant to acidic environments during exposure.Conclusion　Transient exposure of stainless steel to an acidic oral environment can increase elemental release significantly. So acid resistance of magnetic retainers was relatively weak, and it would affect the life span of magnets.

Key words: magnetic retainer, corrosion resistance, artificial saliva