Hydroxyapatite cement scaffolds with controlled macroporosity: fabrication protocol and mechanical properties.

Precipitated hydroxyapatite cement scaffolds with macroporosity of controlled size and shape were successfully built using a solid freeform fabrication process. The negative macroporosity was designed using CAD software and built with an inkjet machine. A slip casting process using a plaster mold was used to precipitate the cement and manufacture samples for mechanical testing. The negative macroporosity was then extracted from the samples using a thermal process. Compression, tension and torsion tests were completed successfully on the precipitated hydroxyapatite cement samples in moist condition. Elastic and strength properties were measured for these three loading cases and compared to the plain hydroxyapatite cement properties reported in a previous study. Homogenization theory was applied to estimate the elastic properties of the manufactured scaffolds. A good correlation was obtained between the experimental data and the theory.