Oral antiseptics and nickel–titanium alloys: mechanical and chemical effects of interaction
Abstract
The
effect of oral antiseptics on the corrosion of nickel–titanium (NiTi)
alloys with various coating was investigated. Uncoated, titanium
nitride-coated and rhodium-coated NiTi archwires (0.020 × 0.020″) were
tested in interaction with artificial saliva pH 4.8 and oral antiseptics
based on hyaluronic acid (Gengigel), chlorhexidine (Curasept) and
essential oils in alcohol base (Listerine). The dynamics of nickel and
titanium ions release were recorded during 28 days. Springback ratio and
modulus of resilience were assessed by three-point bending test. The
results showed that corrosion of NiTi is related to type of antiseptic
mouth rinse and coating formulations. Exposure to an artificial saliva
and antiseptics tend to reduce flexibility and resilience of NiTi
archwires. The influence of the media is more significant than the
influence of the type of the alloys coating. The largest release of
nickel ions is in the first 3 days. Antiseptics do not cause further
deterioration of the elastic properties in uncoated NiTi compared to
saliva. As a result of exposure of nitrified NiTi wires in Listerine,
there is bigger release of nickel ions, decrease in elastic properties
and lower force delivery in unload. Listerine tends to reduce elastic
properties of rhodium-coated wires also. In conclusion, except for
Listerine, changes of mechanical characteristics induced by antiseptics
are small and would not have a clinically important impact. Generally,
Curasept would be the most suitable option.
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