1998 Fiscal Year Final Research Report Summary
Experimental Polyalkenoate Cements Based on the Bioactive Glass
| Project/Area Number |
09470439
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
補綴理工系歯学
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
MATSUYA Shigeki Kyushu Univ., Faculty of Dentistry, Associate Professor, 歯学部, 助教授 (00108755)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OHTA Michio Kyushu Univ., Faculty of Dentistry, Professor, 歯学部, 教授 (30037824)
MATSUYA Youko Kyushu Univ., Faculty of Dentistry, Research Associate, 歯学部, 助手 (50128097)
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Keywords | bioactive glass / glass ionomer cement / NMR / silicate glass / setting mechanism / IR / polyacrylic acid |
|---|
| Research Abstract |
We -prepared a new glass ionomer cement using the bioactive CaO-P_2O_5-SiO_2(-MgO) glasses and investigated its setting process using FT-IR and MAS NMR analyses and their bioactivity. Compressive strength of the cements depended on the glass composition and the maximum strength of 33.3 4.7 MPa was obtained with the cement using the glass composition of MgO : 4.6, CaO : 44.9, SiO_2 : 34.2 and P_2O_5 : 16.3% in weight. The FT-JR analysis shows that COON group in the polyacrylic acid decreased and carboxylate ion (COO-Ca^<2+>) increased after the setting reaction. A broad signal appeared around -82 ppm in ^<29>Si MAS-NMR spectra of the glasses and a new signal corresponding to hydrated silica gel formation appeared around -102 and -111 ppm after setting. This fact suggests that Ca^<2+> was released from the glass powder to form the carboxylate salt and that a degree of polymerization in silicate network increased, With the glass containing Al, Al ion existed as tetrahedral position in the original glass. As the setting reaction proceeded, however, it was released from the glass as hexa-coordinated Al^<3+> hydrate ion to form cross-linking with COO^- groups in the acid molecule. The setting mechanism of the cement was found to be essentially the same in the conventional glass ionomer cement. In vitro bioactivity of the set cement was inferior to that of the original glasses. This was probably because of capture of Ca^<2+> ion by the carboxyl group in the acid molecule. It is necessary to improve the mechanical strength and bioactivity to use the cement as an alternative of the hard tissue. For that purpose we should consider the composition of the glass, the sort of the polymer acid and its molecular weight.
|
