title: Mechanical properties of calcium sulphate/hydroxyapatite cement.
abstract: Setting times, volume after setting, injectability and hardness (at 37 degrees C in contact with Ringer's solution) were determined for cements made of mixtures of calcium sulphate hemihydrate (CS) and hydroxyapatite (HA) with a range of compositions. The purpose of these experiments was to determine the behaviour of a mixture that could be used as an injectable cement for orthopaedic applications, including spinal fusion. A suitable mixture consisted of 60% CS and 40% HA by mass; a slurry was made by mixing solid (36 g) with water (15 cm(3)). The slurry had initial and final setting times of 5.7+/-1.3 min and 19.6+/-0.7 min (mean +/- standard deviation), respectively. The hardness of the cement did not systematically increase or decrease in the 72 h following the final setting time. The volume of the cement was 99.8+/-0.4% of the volume of the initial slurry, i.e. there was negligible shrinkage on setting. It was able to withstand a pressure of 7.3+/-1.2 MPa, applied by a hemispherical indenter before the onset of permanent damage, indicating adequate strength for spinal fusion.
authors.affiliation: School of Engineering, Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Dang
authors.initials: D
authors.lastname: Lei
authors.forename: D
authors.initials: D
authors.lastname: Wardlaw
authors.forename: D W L
authors.initials: DW
authors.lastname: Hukins
mesh_terms: D001672:Biocompatible Materials; D002133:Calcium Sulfate / Q000737:chemistry*; D002484:Cementation; D006882:Hydroxyapatites / Q000737:chemistry*; D008422:Materials Testing; D011165:Porphyrinogens / Q000737:chemistry; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D006882:Hydroxyapatites; D011165:Porphyrinogens; C475044:hydroxyapatite cement; C018563:harderoporphyrinogen; D002133:Calcium Sulfate