Self-setting properties and in vitro bioactivity of calcium sulfate hemihydrate-tricalcium silicate composite bone cements

Self-setting biomaterials are widely used for tissue repair and regeneration. Calcium sulfate hemihydrate has been used for many years as a self-setting biomaterial due to its good setting properties. However, too fast a degradation rate and lack of bioactivity have limited its application in orthopaedic field. Herein, tricalcium silicate was introduced into calcium sulfate hemihydrate (CaSO4 center dot 1/2H(2)O) to form a calcium sulfate hemihydrate-based composite, and its behavior as a cement was studied in comparison with pure calcium sulfate hemihydrate. The results indicated that the workability and setting time of the composite pastes are higher than those of pure CaSO4 center dot 1/2H(2)O, and the composite pastes showed much better short- and long-term mechanical properties than those of pure CaSO4 center dot 1/2H(2)O. Moreover, the biphasic specimens showed significantly improved bioactivity and degradability compared with those of pure CaSO4 center dot 1/2H(2)O, indicating that the composite cements might have a significant clinical advantage over the traditional CaSO4 center dot 1/2H(2)O cement. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.