The Animal Experimental Study Of Strontium-oxide Layer Of Moderately Rough Titanium Surface On The Promoting Osseointegration

Bone osseointegration and good initial stability are important basis for the success of implant operation.With the development of the implant technology,the success rate of implant has improved dramatically.However,the bone defects of different patients are various in clinical working,especially for patients with smoking habits,periodontal disease,diabetes or severe bone defect.SLA implant itself may not be able to meet the needs of all patients.The characterizations of implant surface are essential for affecting the speed and degree of bone osseointegration.There are many researches on surface modification,including modifications of physics,chemistry and biology and so on.Recent years,with the growing application of osteoporosis drug strontium ranelate,the modification of strontium has gradually been the focus.The purpose of this study was to make modification to SLA implant via hydrothermal treatment and evaluate the properties of SLA and Sr-SLA implants by characterizations and animal studies in an attempt to investigate the biological effect of Sr-SLA implants and provide a theoretical basis for the modification of implant in future.At first,the micrometer porous implants(SLA implants)were made by grinding,polishing,sandblasting and acid corrosion.Next,Strontium-containing SLA implants(Sr-SLA implants)were produced by hydrothermal treatment using a Sr-containing solution(Sr(OH)?·8H?O)with the best parameters investigated by previous research which could be sustainable to release strontium in a certain time.SEM results showed that both Sr-SLA and SLA surfaces exhibited typical isotropic irregular indentations caused by sandblasting and double acid etching at micrometer and submicrometer scales,while the Sr-SLA surfaces exhibited more thickly dotted nanostructures made of heterogeneous granules with a size of nearly 50 nm in diameter at nanoscales,none on the SLA surface.AFM results showed that Sr-SLA surfaces exhibited more bumps and protrusions of different size than SLA surfaces.It was dedicated that the Sr-SLA surface produced by hydrothermal treatment not only retained the original microscale structures,but also formed the nanoscale structures.XPS and XRD results showed that SrTiO3 on the Sr-SLA surface,none on the SLA surface.Moreover,as immersion time progressed,the release amount of Sr ions from the Sr-SLA implant decreased,from the ICP-MS results.There was no significant difference between the Sr-SLA and SLA in terms of Vickers hardness.Then,Sixty-four SLA and Sr-SLA implants were inserted into the proximal tibiae and femoral condyles of sixteen non-osteoporotic New Zealand white rabbits.The biological effects were evaluated by removal torque(RTQ)testing and histomorphometric analysis after 3 and 6 weeks post-surgery.The animal experiments indicated that strontium-oxide layer on the SLA surface had the potential to improve implant osseointegration in non-osteoporotic rabbits.In conclusion,this study explored the characterization and biological effect of Sr containing SLA micro/nano-structured surface produced by hydrothermal treatment.It was found that Sr-SLA implants could improve the implant osseointegration.This research provides experimental basis and theoretical basis for the modification of implant surface in future.