Effect of incorporation of nano bioactive silica into commercial Glass Ionomer Cement (GIC)

Four types of bioactive nano-silica were prepared by different methods, and were used to improve commercial dental Glass Ionomer Cement (GIC) bioactivity. The prepared powder samples were characterized by X-ray diffraction (XRD) to identify the formed phase; particle size and morphology were assessed by transmission electron microscope (TEM). The bioactivity of the prepared powder samples and its dental cement blends were applied in simulated body fluid (SBF). The change in surface morphology and composition after soaking in SBF after week at 37°C were determined by scanning electron microscopy with energy dispersive spectroscopy (SEM with EDS) and Fourier transform infrared analyses (FTIR). Our results confirmed that the prepared silica powder exists in nano-scale. Precipitations of carbonate–apatite on the silica surface were observed by FT-IR spectroscopy and scanning electron microscopy. Silica dissolution and re-precipitation phenomena were also observed from SEM. The relationship between both phenomena during the in vitro test is discussed mainly in terms of structural and microstructural features of the silica. Combination of bioactive nano-silica with dental cement improves its bioactivity, which may be helpful to overcome marginal gap formation which is major disadvantage of the commercial dental cement