2001 Fiscal Year Final Research Report Summary
Modification of Electrochemically Deposited Apatite Using Supercritical Water and its Dental Application
| Project/Area Number |
12671912
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
補綴理工系歯学
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| Research Institution | Kagoshima University (2001)
Aichi Gakuin University (2000) |
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Principal Investigator |
BAN Seiji Kagoshima University, Dental School, Professor, 歯学部, 教授 (10159105)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Supercritical water / Electrochemical deposition / Apatite / Dental implant / Surface modification |
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| Research Abstract |
Supercritical water was used as a modification method of electrochemically deposited apatite on pure titanium. The apatites were coated on a commercially pure titanium plate using a hydrothermal-electrochemical method. A constant direct current at 12.5 mA/cm^2 was loaded for 1 hr at 25, 60, 100, 150 and 200℃ in an electrolyte containing calcium and phosphate ions. The deposited apatite on the titanium substrate was stored in supercritical water at 450℃ under 45 MPa for 8 hr. With this treatment, the crystallinity of the apatites increased, sharp edges of the deposited apatites were rounded off, and the bonding strength of the titanium substrate to the deposited apatites significantly increased. On the other hand, weight loss in 0.01 N HC1 decreased and the weight gain rate in a simulated body fluid also decreased with this treatment. It is suggested that the modification using supercritical water improved the mechanical strength of the deposited apatite, but worsened its bioactivity.
Furthermore, pure titanium and 12 % AuPdAg alloy plates after sandblasting were treated with super critical water )SCW) in an autoclave under 45MPa at 450℃. Field emission-type scanning electron microscopy showed that fine particles, less than 0.2μm, were formed on the cpTi with SCW and thick layer was formed on the surface heated at 600℃ in air. X-ray diffractometric study revealed that TiO_2 was formed on the cpTi with both the treatments. The bonding strength of two types of veneering resin to both metal plates with and without the above treatments were determined. The bonding strengths of cpTi with SCW to the one resin were larger than the other conditions )p<0.05).
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