| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
In this project, the objective is to evaluate risks of the galvanic corrosion in the three types of the combination groups including dental precious and non-precious alloys contacted with titanium and titanium alloys, dental precious alloys and titanium contacted with several stainless steels for dental magnetic attachments, and orthodontic wires with silver solder. Although, titanium and titanium alloys increase Ag and Cu ions released from the precious alloys in the first group, the combination of Type 4 gold alloy and titanium showed the least total amount of ions released from them. Thus, this combination is probably better adapted to dental implants. On the other hand, titanium and titanium alloy slightly increased the ions released from non-precious alloys, since their rest potentials were close to non-precious alloys. The vest combination with little released Ni ions predictably seemed Co-Cr alloy and titanium, or Co-Cr alloy and Ti-6Al-4V alloy. Dental amalgams contacted with t
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itanium in the first group, released quit a lot of Sn (Conventional type) or Cu (High copper type) ions when the surface area ratio of titanium to the amalgams extremely increased at 10 times. The combination of amalgams and titanium has a risk of the galvanic corrosion. In the second group of the stainless steels and the precious alloys, the ferritic stainless steel SUS447J1 slightly released Fe ions even if it contacted with a high carat gold alloy showing very noble rest potential. Almost stainless steels contacted with Pt-Fe-Nb magnet alloy which had extremely noble rest potential, sometime caused pitting corrosion and released quit a lot of ions, but SUS447J was stable. SUS447J1 is the most suitable stainless steel for the dental magnetic attachment. Soldering increased Fe and Ni ions released from orthodontic Co-Cr and stainless steel when the surface area ratio of the silver solder was getting large at 10 times. Adversely, Sn and Cu ions released from the silver solder, the surface area ratio decreased at 1/10. Less
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