Silicate-substituted bovine-derived hydroxyapatite as a bone substitute in regenerative dentistry

Hydroxyapatite, renowned for its biocompatibility and osteoconductive properties, plays a fundamental role in bone regeneration owing to its resemblance to natural bone mineral, thus offering considerable potential for advancing tissue engineering strategies. In this article, the innovative integration of silicon ions into biogenic (bovine-derived) hydroxyapatite (SiBHA) via a tailored sol-gel process is reported. The resultant SiBHA scaffolds exhibited an interconnected microporous structure with a total porosity of 70% and pore dimensions ranging from 120 to 650 µm. Fourier-transform infrared spectroscopy and X-ray diffraction studies validated the effective incorporation of silicon ions into the BHA lattice, with energy-dispersive X-ray and inductively-coupled plasma mass spectrometry further confirming a Ca/P molar ratio for SiBHA between 1.63 and 1.74. Moreover, SiBHA scaffolds demonstrated commendable chemical and thermal stability. Of note, SiBHA scaffolds were found to display significantly enhanced mechanical properties, including compressive strength and Young's modulus, compared to the control BHA scaffolds. In vitro assessments highlighted the capacity of SiBHA scaffolds to foster cell viability, proliferation, and osteogenic differentiation of Saos-2 cells. Immunohistochemical analysis revealed a significant increase in osteonectin expression, a key bone matrix protein, after 14 days of incubation under osteogenic conditions. These findings highlight the biocompatibility and therapeutic potential of SiBHA scaffolds, suggesting their suitability as biomaterials for dental bone regeneration applications.