Microstructure, physical properties, and bone regeneration effect of the nano-sized β-tricalcium phosphate granules

The nano-sized β-tricalcium phosphate granules for the practical application of bone graft substitutes could be prepared from the wet chemically precipitated β-TCP powders by the liquid-solid mixture route and by controlling the pH of mixture solution to 7.5 within a shorter processing time. The phase purity of prepared β-TCP granules was higher above 99% and their particle sizes ranged from 200 to 650 nm. Also, their average compressive strength was higher at 2.22 MPa. It is considered that the phase purity, particle refinement, and mechanical compressive strength of β-TCP granules could be significantly improved through the β-TCP powders synthesized through the liquid-solid mixture precipitation at pH of 7.5. Meanwhile both the porosity and the specific surface area positively associated with the osteoconductivity for bone regeneration were higher at 75% and 2.50 m(2)/g respectively due to the nano-sized particles of porous β-TCP granules. Furthermore, the histological analysis in beagle mandibular defect showed that β-TCP granules demonstrated remarkable bone regeneration effect compared with that of the non-treatment group, indicating the increased new formation of bone (except for callus) (48.42 ± 6.57%) and rapid resorption (69.49 ± 2.40%) without toxicologically significant changes at 12 weeks after implantation.