Galvanic corrosion behavior of orthodontic archwire alloys coupled to bracket alloys.
The purpose of this study was to provide a quantitative assessment of galvanic corrosion behavior of orthodontic archwire alloys coupled to orthodontic bracket alloys in 0.9% NaCl solution and to study the effect of surface area ratios. Two common bracket alloys, stainless steels and titanium, and four common wire alloys, nickel-titanium (NiTi) alloy, beta-titanium (beta-Ti) alloy, stainless steel, and cobalt-chromium-nickel alloy, were used. Three different area ratios, 1:1, 1:2.35, and 1:3.64, were used; two of them assumed that the multibracket appliances consists of 14 brackets and 0.016 inch of round archwire or 0.016 x 0.022 inch of rectangular archwire. The galvanic current was measured for 3 successive days using zero-impedance ammeter. When the NiTi alloy was coupled with Ti (1:1, 1:2.35, and 1:3.64 of the surface area ratio) or beta-Ti alloy was coupled with Ti (1:2.35 and 1:3.64 of the surface area ratio), Ti initially was the anode and corroded. However, the polarity reversed in 1 hour, resulting in corrosion of the NiTi or beta-Ti. The NiTi alloy coupled with SUS 304 or Ti exhibited a relatively large galvanic current density even after 72 hours. It is suggested that coupling SUS 304-NiTi and Ti-NiTi may remarkably accelerate the corrosion of NiTi alloy, which serves as the anode. The different anode-cathode area ratios used in this study had little effect on galvanic corrosion behavior.
Iijima
Masahiro
M
Department of Orthodontics, Health Sciences University of Hokkaido, Japan. iijima@hoku-iro-u.ac.jp
Endo
Kazuhiko
K
Yuasa
Toshihiro
T
Ohno
Hiroki
H
Hayashi
Kazuo
K
Kakizaki
Mitsugi
M
Mizoguchi
Itaru
I
D002858:Chromium Alloys / Q000737:chemistry; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry; D017097:Electric Impedance; D004563:Electrochemistry; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012965:Sodium Chloride / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry
D002858:Chromium Alloys; D003722:Dental Alloys; D003764:Dental Materials; C023988:beta titanium; C040654:titanium nickelide; D013193:Stainless Steel; D012965:Sodium Chloride; D009532:Nickel; D014025:Titanium