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.