COMPARATIVE STUDY OF THE SETTING REACTION KINETIC OF SEVERAL APATITIC CALCIUM PHOSPHATE BONE CEMENTS

A comparative study between three α-TCP based bone cements has been performed. The study has been focused on the reactivity of the cements in order to know the effect of several processing factors on their kinetic behaviour. The hardening curves and the extent of conversion of α-TCP into a calcium deficient apatite precipitate have been obtained as a function of the hardening time. The factors studied have been the particle size of the α-TCP main reactive phase and the addition of calcium carbonate as a modifying setting additive.

The results showed a strong correlation between the hardening curve and the hydration rate of the main reactive α-TCP phase. However, the results obtained for the cements were statistically different between them. A significant decrease of the particle size of α-TCP was found to accelerate the setting and the hardening of the cement. An increase of the amount of calcium carbonate in the initial powder mixture was shown to decrease the rate of hardening with an important decrease of the compressive strength at saturation.