Despite 40 years of efforts, researchers have failed to provide calcium phosphate bone graft substitutes performing well enough to replace bone grafting procedures: their osteogenesis potential is limited, calcium phosphates are too brittle, and insufficient bone formation in patients. However, there is hope to solve the aforementioned problems.
The calcium phosphate ceramics, the biphasic calcium phosphates (BCP), which are composed of different concentrations of the stable phase, hydroxyapatite (HA), & the more soluble phase, usually composed of β-tricalcium phosphate (β-TCP), have presented significant advantages over other calcium phosphate ceramics due to their controlled bioactivity & balance between resorption/solubilization which guarantees the stability of the biomaterial while promoting bone ingrowth. Depending upon the concentration of the more stable and soluble phases, it is possible to obtain a ceramic that can be applied to large bone defects, in load-bearing areas, and as customized pieces that will maintain their shape over longer periods of time.
The chemical composition of a bioceramic influences the rate of solubilization/resorption as well as its bioactivity. For instance, while HA is slowly resorbed and/or solubilized, calcium sulphate, alpha-TCP, and beta-TCP undergo a much faster process of resorption. A different combination of BCP, HA, alpha, and beta TCPs has been explored for dental and Orthopedic applications.
