Evaluation of the osteogenic performance of calcium phosphate-chitosan bone fillers

There has been recent interest in utilizing calcium phosphates (CaPs) that set in situ for treating bone defects due to the limitations associated with morselized autografts and allografts. However, CaP cements have long setting times, poor mechanical properties, and poor osteoinductivity. This has prompted research toward finding a nonprotein-based compound, such as chitosan, to accelerate setting times and increase osteoinductivity. The purpose of this study was to compare bone growth rates during the early bone healing response achieved using conventionally prepared chitosan-CaP bone filler to an extensively purified chitosan-CaP compound. Both compounds set quickly and stimulated bone formation. Histomorphometry demonstrated a 290% increase in new bone formation when using the conventional chitosan-CaP bone filler and a 172% increase with the highly purified chitosan-CaP compound compared to the increase in bone formation seen with the unfilled control group. The results of this study indicate that a highly purified chitosan-CaP paste stimulated less bone formation than a conventionally prepared chitosan-CaP paste but both pastes have the potential to stimulate bone formation.