Bone Regeneration in Rat Calvaria Using 3D-Printed Scaffolds with Graded Porosity and In Vitro Degradation

Craniofacial bone defects present a significant clinical challenge due to their structural complexity and potential neurological implications. In this study, a three-dimensional (3D) polylactic acid (PLA) scaffold with graded porosity and three pore types was fabricated and subjected to a controlled in vitro degradation process. Dental pulp stem cells (DPSCs), which are known for their osteogenic potential, were seeded on the scaffolds to evaluate their osteoconductive performance in a critical-size calvarial defect model in Wistar rats. In vitro assays revealed no significant changes in surface morphology, weight, pH, and mechanical properties over 0, 60, 100, 140, and 180 days of degradation. However, scaffolds degraded for 60 days demonstrated enhanced biological activity in cell-based assays and were therefore selected for in vivo implantation. Microcomputed tomography and bone mineral density analysis indicated that the group receiving degraded scaffolds without cells exhibited the most substantial new bone formation, suggesting effective osteoconductive properties. These findings represent a promising step toward translational medicine and highlight the potential for clinical application, pending further preclinical validation.