Niobium Oxide Coating Enhances Integration in Titanium Implants

Objectives:   The purpose of this study is to evaluate the effect of niobium oxide coating on the in vivo performance of titanium implants.

Methods: Ten New Zealand white rabbits weighing 3.5-4.5 kg were used. Forty screw-type dental implants made from CP titanium with 3.5 mm in diameter and 5.5 mm in height were obtained.  Twenty screws were first coated with niobium and then anodized by Indiana Nanotech using 0.5% HF at 25V.  These niobium oxide coated titanium screws along with the uncoated titanium screws were implanted in the tibia of rabbit.  The animals were sacrificed 6 weeks and the section in tibia extending 5 mm distally and proximally to the implants was obtained en bloc. Ten retrieved samples from each group were tested for removal torque using a digital torque gauge.  Ten retrieved samples from each group were embedded undecalcified in polymethyl methacrylate, sectioned, and then stained with McNeals Tetrachrome (von Kossa followed by toluidine blue) to detect mineralized tissue.  

Results:   The result showed that the removal torque of the control group and the NbO group are 20.01+/-7.62 Ncm and 32.30+/-9.13 Ncm.  The NbO group showed a 37.5% increase compared to the control group.  There was a statistic difference between the two group (p<0.05).  New bone is seen to grow between the original cortical bone and the implants forming intimate contact with the implants surface.  Under histomorphometric analysis, the bone to implant contact of the control implant and the NbO-coated implant were 66+/-18% and 71+/-21%.  There were no statistic differences between the two groups.

Conclusions:   Though there were no statistical differences in the BIC, the removal torque for the NbO-coated implants were significantly higher. The result may indicate that the bonding between bone and NbO coating is higher than the bonding between bone and machine titanium surface.