2003 Fiscal Year Final Research Report Summary
A Clinical Study n Discoloration of the Dental Casting Alloys
| Project/Area Number |
13672061
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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 | Tsurumi University |
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Principal Investigator |
TAKAYAMA Yasuko Tsurumi University, School of Dental Medicine, Assistant Professor, 歯学部, 助手 (30175939)
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| Co-Investigator(Kenkyū-buntansha) |
MIURA Eiji Tsurumi University, School of Dental Medicine, Assistant Professor, 歯学部, 助手 (20157423)
HIRANO Susumu Tsurumi University, School of Dental Medicine, Professor, 歯学部, 教授 (00089400)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Ag-Pd-Au alloy / Titanium / discoloration / color difference / Oral Microorganism / Heat treatment / Surface Observation / electrical potential |
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| Research Abstract |
The present study was to evaluate discoloration and accretion on the polished surface of dental cast metal in the oral cavity.
1. The findings indicated in vitro that the production of CH_3SH, H_2S was related to the discoloration of Au-Ag-Pd alloy. The dicoloration of Au-Ag-Pd alloy may also be related to the oral conditions such as periodontics, halitosis and oral care.
2. The prevention of discoloration was influenced by composition of Ag-Pd-Au alloys (Cu : 10.0〜20.0 mass%, Au 12.0 or 20.0 mass%). But it was difficult to prevent to the discoloration of commercially available Ag-Pd-Au alloys with the current compositions for patients having high corrosive influence on the mouth.
3. Cast clasps ware conventionally cast using Ag-20Pd-12Au alloy. After casting, the heat treatment was performed as wing manners : 1) Heated at 800℃ for 1 hour and quenched in water. 2) Heated at 800℃ for 1 hour and air cooled. As a control, cast clasps without heat treatment. Although there are significant differences in the luminance among two heat treatment and control, the luminance was markedly decreased in all conditions after delivery. On the high discoloration subjects heat treatments might be little effect.
4. The pure titanium and Ag-Pd-Cu-Au alloy were installed in the partial denture by cooperating in three patients and each denture was used as usual for two months. The surfaces of the discolored specimens were confirmed to be covered with the spherical accretion. The accretion of titanium was taken away by Argon ion etching in X-ray Photoelectron Spectroscopy and its thickness was confirmed to be 0.3〜0.5μm. However, the thickness of the accretion in Ag-Pd-Cu-Au alloy could not been estimated because it was taken away by Argon ion etching.
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Research Products
(8 results)
