title: Deterioration in the superelasticity of Ti sputter coated on NiTi orthodontic wire.
abstract: To evaluate the deterioration in the superelasticity of Ti-coated NiTi orthodontic wires, titanium was coated onto wires to form a 1-microm thick film using radio frequency magnetron sputtering. In superelasticity cycle tests, the sigma5.0 value (the stress at 5.0% strain) of a Ti-coated wire was lower than that of a non-coated wire by 6.2% after one cycle, and by 10.4% after 20 cycles. In a three point bend tests, the L2.0 value (the load at 2.0 mm deflection) of a Ti-coated wire was 2.55 N, and this was reduced by 39.0% of the L2.0 value of a non-coated wire (4.18 N). After the non-coated and the Ti-coated wires had been immersed in physiological saline for periods of four and eight weeks, the concentration of Ni ions released into each solution was detected using MIP-Mass, and Ni peak intensity of the wires was measured using XPS. After eight weeks, the concentration of Ni ions released from the non-coated and the Ti-coated wires was 657 and 135 ppb, respectively. In a clinical test, no inflammation was observed during the entire attached period of four weeks in both the non-coated and the Ti-coated wire. In the Ti-coated wire, little exfoliation of the Ti-coating was observed using SEM and EDS. It was concluded that Ti-coated NiTi orthodontic wire has much potential for its application, with a low probability of causing any Ni allergy.
authors.affiliation: Applied Systems Engineering, Graduate school of Science and Engineering, Tokyo Denki University, Ishizaka, Hatoyama, Hiki, Saitama 350-0394, Japan. ozeki@bme.f.dendai.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Ozeki
authors.forename: T
authors.initials: T
authors.lastname: Yuhta
authors.forename: H
authors.initials: H
authors.lastname: Aoki
authors.forename: T
authors.initials: T
authors.lastname: Asaoka
authors.forename: T
authors.initials: T
authors.lastname: Daisaku
authors.forename: Y
authors.initials: Y
authors.lastname: Fukui
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D019232:Dental Restoration Failure; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods*; D005260:Female; D006244:Hardness; D006801:Humans; D008297:Male; D009532:Nickel / Q000737:chemistry*; D009969:Orthodontic Wires; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium