Study of particle size dependant reactivity in an α-TCP orthophosphate cement

Calcium phosphates have been of great interest in the field of medicine for many decades due to their biocompatibility, hardening properties and diverse areas of application. In this study two different alpha phase tricalcium phosphate powders were produced of distinctly different particle size distributions. These two powders were then tested for reactivity and phase evolution. X-ray diffraction was used to characterise the beginning and final products and the exotherm were measured with an isothermal calorimeter. The powders were then viewed relative to their starting properties and differences were drawn. Fine material exhibited a much larger exotherm, which was not directly proportional to the difference in surface area of the particulate. The difference has been attributed to the variant concentrations of nucleation sites assisting the ionic dissolution and precipitation reaction. For proper and ultimately efficient use of this material in the clinic it remains important to fully understand and have control over reactivity. Higher success rates and more reliable fracture fixation will result.