Long-term study of osteoconductivity of bioactive porous titanium metals: Effect of sodium removal by dilute HCI treatment

摘要

In a previous study, we have reported that sodium removal by dilute hydrochloric acid (HC1) converted the sodium titanate layer on the surface of an alkali-treated porous titanium into titania with a specific structure that has better bioactivity than sodium titanate. We have shown that a porous titanium with this treatment have good osteoinductivity in soft tissue of canines. In the present study, we investigated the effect of this treatment on the osteoinductive abilities of porous bioactive titanium implant in the long term. Three types of surface treatments were applied: (a) no treatment, (b) alkali, hot water, and heat treatment ( conventional treatment: W-AH treatment), and (c) alkali, dilute HC1, hot water, and heat treatment (Na-free treatment: HC1-AH treatment). We then examined the osteoconductivity of the materials implanted in the femoral condyles of Japanese white rabbits at 6, 12, 26, and 52 weeks. The results showed that the bone ingrowth in HC1-AH porous bioactive titanium was significantly higher than in W-AH porous bioactive titanium at 52 weeks. Therefore, sodium removal has a positive effect on the osteoconductivity of the porous bioactive titanium implant in the long term.