Characterization of a novel calcium phosphate composite bone cement: flow, setting, and aging properties.

The flow, setting, and aging characteristics of a newly developed calcium phosphate/calcium aluminate composite orthopaedic cement were studied. The effect of vibration on the flow of the cement paste was studied and found to greatly enhance placement. The setting times of this cement were dependent on temperature and decreased with increasing temperatures. At 37 degrees C, the working and setting times were 6.3 +/- 0.3 and 12.8 +/- 0.4 minutes, respectively. Hydration and conversion of the cement phases continued while specimens were stored under simulated, physiological conditions. A cumulative increase in mass of 8.23 +/- 0.65% was observed over a 14 month test period. During this time, the cement was found to expand slightly, 0.71 +/- 0.39%. X-ray diffraction was used to characterize the crystalline phases present during hydration and conversion. The calcium aluminate in the cement hydrated and formed calcium aluminate chloride hydrates, while no changes were observed in the beta-tricalcium phosphate during the testing period.