NON-DECAY TYPE FAST-SETTING CALCIUM-PHOSPHATE CEMENT - HYDROXYAPATITEPUTTY CONTAINING AN INCREASED AMOUNT OF SODIUM ALGINATE

A hydroxyapatite [(HAP) Ca-10(PO4)(6)(OH)(2)] putty that behaves like a putty or self-curing resin was made by increasing the amount of sodi um alginate in non-decay type fast-setting calcium phosphate cement (n d-FSCPC). nd-FSCPC became viscous as the sodium alginate concentration was increased. The best handling properties were obtained when nd-FSC PC contained 8% sodium alginate in its liquid phase. When a 2-kg glass plate was placed on the paste, HAP putty spread to form an area three times that of FSCPC paste. Thus, HAP putty is expected to be easier t o use than FSCPC in the filling of bone defects. HAP putty did not dec ay; in fact, it set within approximately 20 min when immersed in disti lled water immediately after mixing. The wet diametral tensile strengt h value of HAP putty was approximately 12 MPa after 24 h, the same as that for nd-FSCPC containing 0.5% sodium alginate in its liquid phase, or FSCPC that is free from sodium alginate. The elements constituting set HAP putty were examined using powder X-ray diffraction and found to be predominantly apatitic minerals after 24 h. Since the handling p roperties of a putty or self-curing resinlike cement are very useful i n certain surgical procedures, HAP putty made by increasing the sodium alginate concentration in nd-FSCPC is potentially a valuable new biom aterial for use in plastic and reconstructive surgery, as well as oral and maxillofacial surgery. (C) 1997 John Wiley & Sons, Inc.