| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Masaaki Osaka Dental University, Department of Biomaterials, Professor, 歯学部, 教授 (50067055)
OGURA Hideo The Nippon Dental University School of Life Dentistry at Nigata, Department of Dental Materials Science, Professor, 新潟生命歯学部, 教授 (60095099)
GOTO Shin-ichi The Nippon Dental University School of Life Dentistry at Nigata, Department of Dental Materials Science, Associate Professor, 新潟生命歯学部, 助教授 (10105504)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
Dental alloys containing indium, indium alloys with additive ratios of 10%, 15% and 20% ; alloys of silver, palladium, gold, copper and indium with additive ratios of 2%, 4% and 6% ; and a gold alloy for porcelain bonding were examined to evaluate the embryotoxicity risk by accelerated extraction with diamond powder in Dulbecco's Modified Eagle Medium (DMEM). An examination of the embryotoxicity level of each extract using mouse-derived ES-D3 cells demonstrated the possibility of embryotoxicity only for silver-20%indium alloys. The ES-D3 cells in artificial saliva did not differentiate.
This suggests elution of the alloy content due to occlusal wear. Accordingly, we simulated the actual conditions of mouth elution of the silver-20% indium alloy, the alloys of silver, palladium, gold, copper and 6%indium using the following procedure. First, anchor teeth for the left and right molars were fixed in a maxillomandibular model, and full cast crowns were made using the above alloys. Finally, the crown surface was polished, and the upper jaw of the model was repeatedly moved for 6 or 12 hours, in order to apply repetitive wear motions to the crown surface. Measurements with ICPS measured the amounts of indium, silver, palladium or copper ions eluted from the alloys to be less than 1 ppm. Furthermore, it was suggested that the embryotoxicity of the alloys of silver, palladium, gold, copper and indium were weaker than those of silver-indium alloys.
To examine the supposed embryotoxicity risk of the alloy of Ag-20%, a developmental toxicity test was conducted by the rat whole-embryo culture method. The test results showed that there was no significant difference in yolk-sac diameter, crown-rump length, head length, number of somites and protein content compared to those in the control group. Therefore, no abnormalities were found in the embryos.
The results demonstrate that the embryotoxicity risk of alloys containing indium examined in this test is very low.
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