One-pot synthesis of hydroxyapatite–silica nanopowder composite for hardness enhancement of glass ionomer cement (GIC)

Hydroxyapatite–silica nanopowder composite was prepared using one-pot sol–gel technique. The morphology of the powder consists of a mixture of spherical silica particles (∼30 nm) embedded within the elongated hydroxyapatite (∼103 nm). The synthesized nanoparticles were incorporated into commercial glass ionomer cement (GIC) and Vickers hardness was evaluated. Results shown that the addition of the nanopowder composite gave ∼73% increment in the hardness compared to the pure GIC. Higher content of hydroxyapatite–silica nanopowder resulted in dense cement and produced a stronger GIC and the application of this material with improved hardness property might lead to extend the clinical indications, especially in stress bearing areas.