Abstract
The goals of the study were to investigate the effects on bone bioactivity of a titanium dioxide layer formed by hydrothermal oxidation of a titanium surface with hydrogen peroxide（H2O2） and loading with fibroblast growth factor-2（FGF-2） in vitro and in vivo.
Ti-6Al-4V discs were hydrothermally oxidized with H2O2 and then loaded with FGF-2. After cytotoxicity testing, Ti-6Al-4V mini-implants were subjected to the same treatment, and their osteogenic potential was evaluated histologically in a rat model.
H2O2 hydrothermal oxidation resulted in a dense porous network structure and hydrophilic changes, which improved retention of FGF-2. Morphologically, the cell density was higher, cell elongation was more pronounced, and the cell adhesion area was significantly higher in FGF-2-loaded cells than in those without FGF-2. In a cell proliferation assay using mouse osteoblast-like cells, absorbance tended to increase over time, especially in the FGF-2 group after 7 and 14 days. In a bone differentiation assay based on ALP activity, there was a significant increase in the FGF-2 group after 14 days. In the rat model, H2O2 hydrothermal oxidation and FGF-2 loading both resulted in more laminar bone tissue in the bone marrow around the mini-implant.
These results suggest that titanium surface functionalization using H2O2 hydrothermal oxidation and FGF-2 may promote initial cell adhesion, proliferation and osteodifferentiation, and enhance bone bioactivity. These effects all contribute to the early bonding of an implant with the surrounding bone.
