Non-decay type fast-setting calcium phosphate cement: setting behaviour in calf serum and its tissue response.

Non-decay type fast-setting calcium phosphate cement (nd-FSCPC) was evaluated in terms of its setting behaviour in calf serum and its tissue response to investigate the feasibility of its clinical use in surgical applications. Non-decay type cements were prepared by adding various amounts of sodium alginate to the liquid phase of base cements, fast-setting calcium phosphate cement (FSCPC) and conventional calcium phosphate cement (c-CPC). Cement pastes were immersed in serum at 37 degrees C immediately after mixing, and decay behaviour, setting time and mechanical strength were measured to evaluate the possibility of their use in surgical applications. Also, nd-FSCPC was implanted into rat subcutaneous tissue for the initial evaluation of biocompatibility of this potential bioactive cement. nd-FSCPC set in approximately 6-7 min in serum, even when the cement paste was immersed in the serum immediately after mixing, whereas c-CPC and FSCPC decayed completely upon immersion. nd-FSCPC transforms to hydroxyapatite (HA) within 24 h and shows a diametral tensile strength of approximately 4-5 MPa. As a result of transformation to HA, nd-FSCPC showed excellent tissue response when implanted subcutaneously in rats. We conclude that nd-FSCPC has good potential value for use in orthopaedics, plastic and reconstructive surgery, and oral and maxillofacial surgery, where the cement is exposed to blood.