Preparation and characterisation of glass ionomer cements incorporating barium and magnesium ions

The aim of this study is to investigate glass compositions containing BaO and MgO with a view to improve the mechanical properties of conventional glass ionomer cements. Two glass systems based on the compositions of SiO2–Al2O3–CaF2–TiO2 and SiO2–Al2O3–CaF2–ZrO2 were prepared and reacted with an in-house produced co-poly(alkenoic acid) to produce glass ionomer cements. X-ray diffraction and X-ray fluorescence were used to determine the phases and chemical compositions of the glass after melting. The morphologies of the glass powder and cement surfaces were analysed by SEM. The compressive strength and the working and setting times of the cements were also measured. Cements prepared from glass systems of SiO2–Al2O3–CaF2–TiO2 and SiO2–Al2O3–CaF2–ZrO2 containing barium and magnesium ions showed significantly increased strength compared to their original glasses. ZrBa1Mg1 cement that contained equal amounts of barium/magnesium oxide possessed high cement strength at ∼110 MPa but long setting time at ∼16 min. This cement was found to be promising for further improvement as a filling material.