The corrosion behavior of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material.
Our findings indicate that (1) 2205 stainless steel exhibits better corrosion resistance than 316L stainless steel; (2) when 2205 is coupled with a less corrosion resistant material (316L stainless steel), 2205 stainless steel shows decreases corrosion; and (3) this trend is reduced when the exposed surface areas have a anodic / cathodic ratio less than 1 and that 2205, unlike 316L, is not subject to crevice corrosion.
From the standpoint of corrosion resistance, the use of 2205 as an orthodontic bracket material seems to be justified when the arch wire material is stainless steel or titanium. Use of this alloy could decrease the amount of corrosion products to which a patient would be exposed that could minimize nickel allergy problems potentially associated with orthodontic treatment.