Compressive strength of calcium phosphate cements prepared using different initial setting temperatures

Abstract

The effect of initial setting temperature on the compressive strength of calcium phosphate cements prepared using Ca4(PO4)2O and CaHPO4 was examined. The strength of the initial setting bodies increased with increasing temperatures: the strength of the body heated at 100°C was ∼14 MPa, which was ∼7 times higher than that heated at 37°C. When the setting bodies were soaked in simulated body fluid at 37°C for 24 h, they showed enhanced strength properties owing to the interlocking structure originating from hydroxyapatite formation. The extent of this effect increased with decreasing setting temperatures: the strength of the body heated at 37°C was ∼50 MPa, which was ∼3 times higher than that heated at 100°C. This was due to the rapid formation of hydroxyapatite following initial setting of the bodies treated at higher temperatures and the delayed hydration reaction following soaking in simulated body fluid.