A Feasibility Study Regarding the Potential Use of Silica-Doped Calcium Sulfate Anhydrite as a Bone Void Filler
In the present study, the feasibility of using calcium sulfate anhydrite (CaSO4) pellets as bone void filler is evaluated. The calcium sulfate anhydrite pellets are prepared by dry-pressing calcium sulfate hemihydrate powder, then sintering at elevated temperatures. The remaining porosity within anhydrite pellets is only 7% after sintering at 1000 °C. The growth of CaSO4grains during sintering is very fast. The addition of a small amount of silica (SiO2), <1 wt%, can prevent the coarsening of anhydrite grains during sintering. The microstructure refinement may be related to the formation of CaSiO3 particles at the boundaries of the CaSO4 grains. The SiO2-doped anhydrite pellets thus exhibit higher compressive strength. Moreover, the degradation of SiO2-doped anhydrite pellets is slower than that of anhydrite pellets. The slow degradation rate is likely attributable to the dissolution of minute amounts of SiO2 in CaSO4.