HAp/PLGA/Chitosan Scaffolds Fabricated by Freeze-Drying and 3D Printing for Bone Regeneration: In Vitro Evaluation and Finite Element Analysis

Tooth loss and bone resorption of the alveolar cavity caused by dental caries and periodontal disease remain major clinical challenges that compromise oral function. Tissue engineering approaches based on biocompatible scaffolds have emerged as promising strategies for bone regeneration; however, the influence of fabrication methods on scaffold performance remains unclear. This study developed hydroxyapatite/poly (lactic-coglycolic acid)/chitosan scaffolds (HAp/PLGA/CS) using freeze-drying and 3D-printing techniques and evaluated their physicochemical, biological, and biomechanical properties. The morphology, porosity, elemental composition, and mechanical properties of the scaffold were characterized, while the biocompatibility and osteogenic potential were evaluated using human dental pulp stem cells (hDPSCs). Finite element analysis (FEA) using COMSOL Multiphysics® Version 6.2. was performed to evaluate scaffold behavior under simulated dental implant loading conditions. The 3D-printed scaffolds exhibited significantly higher cell viability than the freeze-dried scaffolds, reaching approximately 85% in the 50% filling group compared with 50% in the freeze-dried group. Microstructural analysis revealed interconnected hierarchical porosity, including macro-, micro-, and submicrometer scale pores. Although the 50% infill scaffold showed the highest cell viability, the 70% infill scaffold demonstrated the most favorable osteogenic profile, with enhanced expression of RUNX2 and OSX. Both types exhibited degradation profiles compatible with early bone regeneration. FEA simulations indicated that further mechanical optimization is required to improve load transfer and reduce deformation at the implant–scaffold interface. Overall, HAp/PLGA/CS scaffolds showed potential as experimental bioactive platforms for bone tissue engineering, with 3D-printed scaffolds providing greater architectural control and favorable early osteogenic responses. However, the translational relevance of these findings remains preliminary and requires validation through long-term degradation studies, in vivo bone regeneration and osseointegration models, cyclic mechanical testing, and implant fixation experiments.