The effects of calcium phosphate cement particles on osteoblast functions

Calcium phosphate cements (CPC) are increasingly used in the orthopedic fie ld. This kind of cement has potential applications in bone defect replaceme nts, osteosynthetic screw reinforcements or drug delivery. In vivo studies have demonstrated a good osteointegration of CPC. However, it was also obse rved that the resorption of CPC could create particles. It is known from or thopedic implant studies that particles can be responsible for the peri-imp lant osteolysis. Biocompatibility assessment of CPC should then be performe d with particles. In this study, we quantified the functions of osteoblasts in the presence of beta-TCP, brushite and cement particles. Two particle s izes were prepared. The first one corresponded to the critical diameter ran ge 1-10 mu m and the second one had a diameter larger than 10 mu m. We foun d that CPC particles could adversely affect the osteoblast functions. A dec rease in viability, proliferation and production of extracellular matrix wa s measured. A dose effect was also observed. A ratio of 50 CPC particles pe r osteoblast could be considered as the maximum number of particles support ed by an osteoblast. The smaller particles had stronger negative effects on osteoblast functions than the larger ones. Future CPC development should m inimize the generation of particles smaller than 10 mu m. (C) 2000 Elsevier Science Ltd. All rights reserved.