2001 Fiscal Year Final Research Report Summary
Titanium superstructure by a resin pattern material with non-polymerization shrinkage and a thermal expansion typed investments
| Project/Area Number |
12671881
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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 | Osaka University |
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Principal Investigator |
TAKAHASHI Junzo Graduate School of Dentistry, Osaka University, Professor, 大学院・歯学研究科, 教授 (80029149)
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| Co-Investigator(Kenkyū-buntansha) |
TERAOKA Fumio Graduate School of Dentistry, Osaka University, Assistant Professor, 大学院・歯学研究科, 講師 (00099805)
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| Project Period (FY) |
2000 – 2001
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| Keywords | metallic compound / ZrC / ZrN / compensation of casting shrinkage / investment for titanium / casting accuracy / thermal expansion rate / surface roughness |
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| Research Abstract |
Three different chemical substances were added to a liquid component of a self-curing acrylic resin (Pattern Resin, GC).
OXO (surfactant), ACMO (monomer) and ESCOURON (coumarone-indene resin) were selected as substances. The addition of 2 wt%-OXO to liquid reduces linear shrinkage to 0.04 %, about 1/3 of the shrinkage of the basic resin.
The effect of the addition of various metallic compounds on thermal expansion of an investment (Selevest D) was examined. Then, ZrC and ZrN were selected as additives to the investment. Investments added 3.0, 3.5, 4.0 and 5.0 wt% of ZrC and 5.0, 5.5, 6.0 and 7.0 wt% of ZrN were prepared. All investments showed setting shrinkage of about 0.5%. The thermal expansion of investments increased with the amount of Zr compounds and heating temperature, and remained after cooling at room temperature. The compressive strength of investments decreased with the amount of Zr compounds and firing temperature.
Then, pure titanium was cast into these investment-molds, which were fired and cooled down to room temperature.
The surface condition of castings into higher firing temperature was better than that into lower firing temperature. The surface roughness increased with the amount of Zr compounds. The casting accuracy of crowns were 0.21% in 3.5wt%ZrC-700℃ (firing temperature), 0.25% in 5.5wt%ZrN-700℃ and 0. 14% in 5.0wt%ZrN-900℃. In 5.0wt%ZrC, titanium cast crowns had fins which was formed as a result of cracks in the investment.
The casting accuracy could be controlled by the addition content of Zr compounds. The development of new thermal expansion typed investment for titanium was suggested to be possible.
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