Effect of phosphate solution on setting reaction of α-TCP spheres

In this study, effect of phosphate solution on setting reaction of α-tricalcium phosphate (α-TCP) spheres was investigated by employing three phosphate solutions: 0.2 mol/L Na₂HPO₄, 0.2 mol/L NaH₂PO₄ and 0.2 mol/L MCPM-0.1 mol/L H₃PO₄ solution. For the basic study on etting property, two α-TCP spheres were placed together then reacted to different phosphate solutions at 37°C for 10 minutes. When mixed with 0.2 mol/L MCPM-0.1 mol/L H₃PO₄ solution, two α-TCP spheres can be set to form brushite crystals at the interface while they show no reactivity with Na₂HPO₄ or NaH₂PO₄ solution. In order to investigate the setting mechanism between α-TCP spheres, set two-sphere specimens were evaluated in terms of crystal structure and surface morphology. Thus, it was concluded that the reaction between α-TCP spheres and 0.2 mol/L MCPM-0.1 mol/L H₃PO₄ solution resulted in forming of brushite crystals on the surface of α-TCP sphere and the interlocking of brushite crystals is the setting mechanism between α-TCP spheres. This study shows the feasibility to fabricate interconnected porous cement which mimics the morphology of natural bone by connecting many α-TCP spheres together.