The Ca/P range of nanoapatitic calcium phosphate cements

Nanoapatites are apatites consisting of nanometer size crystals. The commercial calcium phosphate cements set by the precipitation of nanoapatitic calcium phosphates in the range 1.5 less than or equal to Ca/P < 1.8 In this study it is shown that a continuum of nanoapatites can precipitate in the range 0.8 < Ca/P less than or equal to 1.5. In order to be formed these nanoapatites need to incorporate K+ ions. In addition they can incorporate some Na+ ions. Upon immersion in aqueous solutions these nanoapatites loose phosphate, K+ and Na+ so that in an open system they are transformed into calcium deficient hydroxyapatite Ca-9(HPO4)(PO4)(5)OH within about 2 months. (C) 2002 Elsevier Science Ltd. All rights reserved.