1992 Fiscal Year Final Research Report Summary
Study on the Adhesive Strength Affected by Interface Reactions between Titanjum and Porcelain during Firing
| Project/Area Number |
03453151
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
補綴理工系歯学
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| Research Institution | Niigata University |
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Principal Investigator |
SHIOKAWA Nobuhiro Niigata University, Dentistry, Professor, 歯学部, 教授 (90018408)
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| Co-Investigator(Kenkyū-buntansha) |
OKAWA Seigou Niigata University, Dentistry, Assistant, 歯学部, 助手 (80143791)
WATANABE Kouichi Niigata University, Dentistry, Assistant, 歯学部, 助手 (20018766)
MIYAKAWA Osamu Niigata University, Dentistry, Assistant Professor, 歯学部, 助教授 (40018429)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Pure titanium / Porcelain fusing / Interface reaction / Multi-layrs / Infrared spectroscopy / X-ray diffraction / Elemental analysis |
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| Research Abstract |
Since a casting technique for pure titanium was developed using a new type casting machine and new investments, pure titanium has been applicable to fixed prothodontics crowns. Titanium is well known for its high corrosion resitance and excellent biocompatibility and it is much less expensive than gold alloys. Furthermore, pure titanium has the intermediate mechnical properties between gold and nickel-chromium alloys and higher sag resistance than these alloys. However, pure titanium is not used for ceramometal restorations because of its low bonding strength caused by both its low thermal expansion and rapid oxidization at high temperature.
To clarify the interface reaction between porcelain and pure titanium during porcelain firing, electron probe microanalyzer (EPMA), X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) have been used to characterize the interface which has emerged by mechanically peeling off. The separation was occurred partly at the interface between titanium and porcelain and partly at the slight inside of porcelain after three times firing at 760ﾟC.
From the elemental analysis of the bonding interface, the following results have been obtained : At the nearest layr to the titanium, potassium content is slightly higher, and on the contrary aluminium and magnesium were not detected practially. Diffusion thickness of titanium to the porcelain was about 3mum. Titanium element was not detected at all when the interface of porcelain was suptter-etched for 4mum. In the surface layr of the titanium side, only oxygen was detected as a diffusing element.
Redox reaction was deduced from the X-ray diffraction results which indicated a decrease in SnO_2 and emerging the beta-Sn (metalic Sn). Considerable amount of Ti_2O was formed at the interface with firing at 760ﾟC for two minutes.
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