Physicochemical and Mechanical Evaluation of Freeze-Dried Hydroxyapatite–?-Tricalcium Phosphate–Polycaprolactone–Copper–Zinc Scaffolds

Bone graft materials are essential for supporting alveolar bone regeneration, particularly in patients with periodontitis who require improved mechanical stability of bone graft scaffold in load-bearing regions. This study aimed to develop and characterize a biphasic bone graft scaffold composed of hydroxyapatite (HAp, 60%) and -tricalcium phosphate (-TCP, 40%) combined with poly(-caprolactone) (PCL) and reinforced with copper (Cu) and zinc (Zn) bioactive ions. The scaffold was fabricated using dimethylformamide (DMF) as the solvent through a freeze-drying process and subsequently compared with a xenograft control. Fourier-transform infrared spectroscopy confirmed the presence of inorganic phosphate groups and organic ester linkages, while the disappearance of the characteristic dimethylformamide (DMF) peak verified the effective solvent removal. X-ray diffraction analysis revealed that calcium phosphorus oxide (86.73%) was the dominant phase and calcium hydrogen phosphate (13.26%) was the secondary phase, indicating that DMF influenced both phase formation and crystallinity. The resulting scaffold exhibited lower porosity (36.39%) than the control (95.79%) but demonstrated substantially higher compressive strength (3.873 MPa) and yield strength (3.024 MPa) than the control (0.980 MPa and 0.537 MPa, respectively). However, water absorption (37.7%) and blood absorption (29.1%) were reduced relative to the control group. Overall, these findings indicate that the HAp–-TCP–PCL-Cu-Zn scaffold (tested specimen) fabricated using DMF provides enhanced structural stability and crystallinity, supporting its potential use in load-bearing bone regeneration applications.

Freeze-drying; Mechanical evaluation; Periodontitis; Physiochemical characterization; Porosity

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