Structure of bioactive glass and its application to glass ionomer cement.
We prepared a new glass ionomer cement using bioactive CaO-P2O5-SiO2(-MgO) glass and investigated its setting process using FT-IR and MAS NMR analyses. The compressive strengths of the cements depended on the glass composition and a maximum strength of 33.3 +/- 4.7 MPa was obtained using cement with the glass composition of MgO:4.6, CaO:44.9, SiO2:34.2 and P2O5:16.3% in weight. FT-IR analysis showed that the COOH group in the polyacrylic acid decreased and carboxylate ion (COO-Ca2+) increased after the setting reaction. A broad signal appeared around -82 ppm in 29Si MAS-NMR spectra of the glass and a new signal corresponding to hydrated silica gel formation appeared around -102 and -111 ppm after setting. This suggests that Ca2+ was released from the glass powder to form carboxylate salt and that a degree of polymerization in the silicate network increased. The setting mechanism of the cement was found to be essentially the same as in conventional glass ionomer cement.
Matsuya
S
S
Department of Dental Materials Engineering, Kyushu University, Fukuoka, Japan.
Matsuya
Y
Y
Ohta
M
M
D001672:Biocompatible Materials / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D019245:Compressive Strength; D005898:Glass / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013329:Structure-Activity Relationship
D001672:Biocompatible Materials; D017610:Calcium Compounds; D005899:Glass Ionomer Cements; D010087:Oxides; D010710:Phosphates; D008277:Magnesium Oxide; D012822:Silicon Dioxide; C016538:lime