Resorbable bioceramics based on stabilized calcium phosphates. Part I: rational design, sample preparation and material characterization

It has long been the goal of biomaterials research in the field of orthoped ics to develop synthetic structures exhibiting comprehensive bioactivity. I n particular, an ideal bone-biomaterial would support the activity of osteo blasts in the development of new bone, while simultaneously being resorbed by osteoclasts as part of the lifelong orderly process of bone remodelling. Such resorbable calcium phosphate-based thin films and bulk ceramics have now been created by the high-temperature processing of a fine precipitate, formed from a colloidal sol and stabilized using an additive such as silico n. The materials have two characteristic features: a phase composition whic h is a mixture of calcium hydroxyapatite and a silicon stabilized tricalciu m phosphate, and a microporous morphology based on inter-connected particle s (0.2-1 mu m in diameter). X-ray diffraction, infrared spectroscopy, nucle ar magnetic resonance spectroscopy, and light scattering experiments indica te that the characteristic phase composition arises during sintering throug h substitution reactions where silicon enters the calcium phosphate lattice under conditions of high chemical reactivity. The crystallographic feature s are linked through the glaserite form of the apatite structure. (C) 1999 Elsevier Science Ltd. All rights reserved.