The Research Of Surface Characteristics And Bioactivity Of Nanostructured Zirconia Coating To Titanium Implant

Objective:To evaluate surface characteristic and osseointegration of zironcia coating implant fabricated by plasma spraying to provide evidence for the development and application of the implant.Materials and Methods:Using a plasma spraying system deposited zirconia coating on pure titanium surface. The titanium substrates were designed into two forms:circular titanium sheet and titanium implant. The circular titanium samples were used to detect the surface morphology, while implants were used to in vivo evaluations.1 Surface morphology:including Scanning electron microscopy (SEM),surface roughness and artificial saliva static contact angle test.2 Implantation experiments:32 New Zealand white rabbits were randomly divided into 4 groups, the plasma-sprayed nano structured zirconia-titanium(A group) and control titanium(B group) implants were implanted into rabbits tibia. Each animal received one zirconia coating implant in one tibial and one Ti implant in the other, for a healing period of 2,4,8, and 12 weeks. At each healing time, a removal torque (RTQ) test was used to assess implant stability, while histological and histometric analyses were used to evaluate osseointegration.Results:1 Surface morphology:pure titanium surface without microporous structure which is characterized by irregularly distributed crystal flakes. On the zirconia coating sample surface, volcano-shaped micropores in similar sizes uniformly dispersed on flat surfaces and microporous aperture is 50～80 μ m, hole depth is about 30 μ m. The Ra of Zirconia coating samples is (1.55±0.21) μm, while the value of pure titanium samples is (0.179±0.11) μm. The contact angles of Zirconia coating samples and pure titanium samples are (54.61 ± 1.80) ° and (74.38 ± 3.61)°, respectively.2 Implantation experiments:Two groups have osseointegration, but the Micro-CT, and optical histological results show that in group A are earlier and more bone formation than group B. Computer quantitative histology results show that the BIC of in group A is significantly higher than group B at 4,8 and 12 weeks (P< 0.05). push-out test results show that implant binding force of two groups have increased over time. The bone bonding force between group have significant statistical difference at different time points (P< 0.01), the bone bonding force is higher in group A than that of control group B at 2,4,8 and 12 weeks (P< 0.05).Conclusion:The above experimental resulta show that the plasma-sprayed nano-zirconia-titanium implants prepared by our group can form good osseointegration between host bone.The material has good biological properties. Comparing with pure titanium implant, the plasma-sprayed nano-zirconia-titanium implants can improve the implant surface bioactivity and enhance the combination intensity implant-bone interface.