An investigation on injectable composites fabricated by 45S5 bioactive glass and gum tragacanth: Rheological properties and in vitro behavior

The injectable composites were formulated from meltderived 45S5 bioactive glass powder and gum tragacanth. The effect of the tragacanth (2 and 4 w/v%) and powder to liquid ratio (P/L= 1.5 to 2.5) on rheological properties, injectability, degradation, swelling, and bioactivity the composites were studied. With increasing the P/L ratio and tragacanth concentration, the force required for injection of the composites is increased. However, the formulated composites show maximum injection force of 15 N, which seems to be appropriate for surgical purposes. The formulated composites indicate positive thixotropic behavior, whereas increasing tragacanth from 2% to 4% lead to deteriorating its behavior. Moreover, thecomposites formulated by 2% tragacanth show much more resistance against degradation and swelling. The bioactivity analyze confirms the formation of flakelike apatite nanostructures on the surface of nanocomposites in initial days of immersion into the SBF solution.