Sintering Improves the Mechanical Properties of Fluorapatite Scaffolds With Open Porous Gyroid Architecture

ABSTRACT Synthetic scaffolds are needed to overcome the limitations of autografts and allografts for the treatment of critical‐sized bone defects. However, fabricating scaffolds with both high porosity and adequate mechanical stability for load‐bearing applications is difficult. This study was therefore undertaken to optimize the strength of fluorapatite (FAp) bone scaffolds. Here, we fabricated FAp scaffolds with a gyroid architecture—selected for its interconnected porosity and surface properties conducive to bone formation. Scaffolds with 50%, 60%, or 70% porosity were prepared by gel‐casting FAp suspensions within combustible 3D‐printed templates, followed by sintering at 1050°C, 1150°C, or 1250°C. Densification accelerated between 1050°C and 1150°C and slowed toward 1250°C, coinciding with reduced microporosity and increased shrinkage and strength. Scaffolds showed 44%–70% porosity and cancellous‐bone‐like compressive strengths (5–13 MPa). Strength and modulus increased with sintering temperature, most notably between 1050°C and 1150°C. SEM imaging revealed a distinct microporous core and surface layer (“skin”), and delamination of this layer suggested opportunities for process optimization. Together with prior in vitro and in vivo evidence of FAp's bone‐regenerative potential, these findings support the suitability of this fabrication approach for future translational studies and subsequent clinical applications.