In vivo osseointegration of Ti implants with a strontium-containing nanotubular coating

Novel biomedical titanium (Ti) implants with high osteogenic ability for fast and good osseointegration under normal as well as osteoporotic conditions are urgently needed. Expanding on our previous in vitro results, we hypothesized that nanotubular, strontium-loaded (NT-Sr) structures on Ti implants would have favorable osteogenic effects and evaluated the in vivo osseointegration of these implants in rats. The structures with nanotubes of different diameters were fabricated by electrochemical anodization at 10 and 40 V, and the amounts of Sr loaded were adjusted by using two hydrothermal treatment times of 1 and 3 hours. Qualitative microcomputed tomography in two and three dimensions showed that the NT-Sr formed with an anodization voltage of 10 V and hydrothermal treatment time of 3 hours best supported bone growth in vivo. Histomorphometric examination of osseointegration also showed that more newly formed bone was found at its surface. The bone–implant contact percentage was highest (92.48%±0.76%) at 12 weeks. In conclusion, the NT-Sr formed with an anodization voltage of 10 V and hydrothermal treatment time of 3 hours showed excellent osteogenic properties, making it an attractive option for Ti surface modification with considerable clinical potential.