Masked stereolithography of hydroxyapatite bioceramic scaffolds: From powder tailoring to evaluation of 3D printed parts properties

Abstract

This paper focuses on the tailoring of hydroxyapatite powders properties for the preparation of highly hydroxyapatite-loaded photocurable organic slurries. The suspensions were evaluated as feedstock for the production of hydroxyapatite scaffolds by stereolithography-based additive manufacturing technique. Then, a debinding-sintering process was designed to avoid the formation of cracks during the pyrolysis of the resin and sintering of the printed parts. A total porosity of 35 vol % and compression strength of 4.9 ± 0.3 MPa were obtained for the specimens printed at 45° to the building platform. A slow degradation rate was observed due to the high degree of crystallinity and intrinsic stability of the hydroxyapatite phase. The tailoring of hydroxyapatite powders was required to lower the viscosity and increase the particle stability of the suspensions. The printed hydroxyapatite scaffolds showed promising results for surgery, in the case of minor or non-load bearing implants requiring slow resorption properties.

Keywords

• Hydroxyapatite
• Rheology
• Sedimentation
• Suspensions
• Mechanical properties
• VAT photopolymerization