Optimized fabrication of DLP-based 3D printing calcium phosphate ceramics with high-precision and low-defect to induce calvarial defect regeneration

Acquiring high-performance calcium phosphate (CaP) ceramics via 3D printing is critical for their applications in bone regenerative repair. In current study, a complete process study of 3D printed CaP ceramics based on digital light processing (DLP) technology was performed to get the ideal implant for the regenerative repair of calvarial defects. The smaller particle size of initial powder would be more favorable to getting slurry with high solid content and low viscosity. CaP green body with high precision and high curing rate could be fabricated at the exposure energy density and exposure time of 6.20 mJ cm−2 and 2 s, respectively. Moreover, the post-curing treatment could eliminate the interlayer cracks and increase the curing rate from 69.78% to 93.91% of green body. After that, the mechanical strength of CaP ceramics increased by 46.34%. In-vitro cellular experiments showed that 3D printed CaP ceramics had good biocompatibility, and could promote the osteoblastic differentiation of BMSCs. In-vivo rat cranial defect implantation revealed 3D printed CaP ceramics exhibited better osteogenic ability than the commercial ones (BAM®), reaching the close level with the autografts. Overall, this study could provide a closed-loop solution for 3D printed CaP ceramics with high-precision and low-defect to induce bone regeneration.