Effect of biofluid environment on the dissolution and flexural strength of calcium phosphate bone cements

This study investigates the dissolution of calcium (Ca2+), phosphorus (P5+), and the transverse strength of commercially available calcium phosphate (CaP) bone cements after immersion in fetal bovine serum and a tissue fluid substitute. It was observed that although a continual increase in Ca2+ and P5+ dissolution was detected in all three test media throughout the 21-day period, no statistical difference existed in the overall Ca2+ release after incubating the cements in the three different media. However, P5+ release after immersion in Tris solution (0.37 +/- 0.02 microgram/mm2) and fetal bovine serum solution (0.347 +/- 0.06 microgram/mm2) was significantly higher when compared with P5+ released (0.03 +/- 0.002 microgram/mm2) in tissue fluid substitute. In addition, no significant difference in transverse strength was observed for samples immersed in the three solutions during the 21-day period. However, the transverse strength for immersed CaP cement bars at 37 degrees C was statistically greater than non-immersed bars set aside at room temperature for the 21-day period (7.78 +/- 1.82 N and 3.19 +/- 0.93 N, respectively). It was concluded from this study that the transverse strength of the CaP bone cements was not significantly affected by the dissolution process but by the temperature at which the bone cement was exposed.