Digital light processing of β-tricalcium phosphate bioceramic scaffolds with controllable porous structures for patient specific craniomaxillofacial bone reconstruction

Abstract

β-TCP scaffolds with four representative pore configurations are prepared for using digital light processing (DLP)-based additive manufacturing. The process optimization, pore design, mechanical properties, and microstructure of the fabricated scaffolds are investigated. The optimal slurry solid content, exposure intensity, slice thickness, and exposure time were found to be 60 wt%, 10 mW/cm2, 25 μm, and 4 s, respectively. The DLP-formed β-TCP bone scaffolds showed 3D interconnected and multilevel pores, achieving porosities of 49%–89% and strut diameters of 200–1000 μm. The primary pore size exceeded 100 μm, and the secondary pore size was less than 10 μm. The porosity significantly affected the mechanical properties of the scaffolds, whereas the pore configuration exerted a minor influence. The prepared scaffolds with a pore configuration of triply periodic minimal surface behaved the best mechanical properties. The compressive strength and elastic modulus of the scaffolds reached 20–30 MPa and 2–4 GPa, respectively. Based on patient’s medical imaging data, large-volume β-TCP scaffolds (∽70 × 40 × 15 mm and 40 × 40 × 4 mm, after sintering) with controlled biomimicking porous structures and anatomical shapes were successfully designed and fabricated by DLP for repair of massively damaged mandible and cranial defects.