Osseointegration of implants surface treated with various diameters of TiO2 nanotubes in rabbit

Abstract

The aim of this study was to evaluate the osseointegration of implants surface treated with various diameters of TiO2 nanotubes (30 nm, 70 nm and 100 nm) in rabbit.RBM surfaced implants (Osstem, Busan, Korea) with 3.5mm in diameter and 8.5mm in length were designated as control group and implants surface treated with various diameters of nanotubes (30nm, 70nm, 100nm) of the same shape were designated as experimental group. The implants were maintained unloaded for 4 and 12 weeks. After this period, the animals were sacrificed and Micro-CT evaluation, histomorphometric analysis (bone to implant contact; BIC, bone volume; BV) and removal torque test, were performed,In micro CT analysis the bone volume results at 12weeks were significantly higher than at 4weeks (p<0.05). The results from micro CT examination showed that 30 nm and 70nm experimental group had the highest bone volume at 4 and 12weeks respectively, however, there were no statistical significant differences (p>0.05). In histomorphometric analysis the BIC and BV results at 12weeks showed significantly higher value than at 4weeks (p<0.05) and the BV results in three consecutive macro threads(Macro BV) at 12weeks showed higher value than at 4weeks, but there were no statistical significant differences (p>0.05). At 4weeks 70 nm experimental group had the highest BIC, BV and Macro BV result. At 12weeks 30nm nm experimental group had the highest BIC and BV result and control group had the highest Macro BV result, however there were no statistical significant differences(p>0.05). The results from removal torque test showed that 70nm experimental group had the significantly higher RTV result compared to other groups at 4weeks (p<0.05). Micro CT, histomorphometric analyses, removal torque test results showed similar pattern that 70 nm experimental group had the highest value at 4weeks and 30nm experimental group had the highest value at 12weeks.On the basis of results above, 30nm and 70nm TiO2 nanotube may have positive effects on osteogenesis and osseointegration depending on the healing time. Further studies confirming the optimal nanotube diameter for earlier osseointegration, implantation in large defect region and drug delivery in the larger size animal model are necessary.