| Total joint replacement is one of the most clinically successful and cost-effective surgical procedures. The procedure can reduce pain and improve function and mobility in patients suffering from end-stage arthritis, injuries from accidents and skeletal tissue disorders. Biological fixation prosthesis, a new type of joint prosthesis, can achieve a firm fixation between the prosthesis and bone tissue without bone cement. The success and lifetime of an implant is largely dependent on the degree of osseointegration at the material–bone interface, especially in load-bearing orthopedic or dental applications. However,a great deal of mechanical and biological factors will cause aseptic loosening of the titanium alloy-based prosthesis, which results in a revision surgery. To minimize the number of revision surgeries needed, various surface modifications have been applied to currently available implants in an attempt to improve osseointegration and increase the lifetime of the implants. Surface coating technique is the most commonly used method. 1. Preparation and surface structural characteristics of HA coating produced by microarc oxidation on porous titanium alloy implants.Objective:To explore the preparation and structural characteristics of HA coating produced by microarc oxidation on porous titanium alloy implants. Methods:Three main methods were used in this experiment to make implants with porous coating:heat casting, plasma rotating electrode and heat sintering. Then, HA coating was made on some of these implants through the technique of microarc oxidation. Observe the surface structure of both two coatings in the scanning electron microscope. Results:The HA coating layer is uniform and firm. Many well-distributed porous structure were observed ,and their diameter is about 1-10μm. Conclusion:Microarc oxidation technique can produce a HA coating of wonderful surface structure on porous implants of a newβtitanium alloy, which will improve the bone formation.2. An animal experiments of HA coating treated by microarc oxidation on porous titanium alloy implants.Objective : The porous-coated implant (PCI group) made by TLM(Ti-Zr-Sn-Mo-Nb) was considered as control group. Observe the following composite coating's interface between the implant and the surrounding bone tissue: porous-MAO(micro-arc oxidation)HA-coated implant(PCI/HA group). Evaluate the newly bone formation of the two groups, and explore the clinical application of MAO as a new methods of surface modification. Methods:Implant the two kinds of test pieces into dog's bilateral femoral marrow cavity. After 4,8,12 weeks , the newly bone tissues around the implants were observed by gross observation and histology and the formation rate of newly bone was calculated and analyzed. Results:Both two surface coatings had good biocompatibility . HA coating produced by MAO technique can significantly improve the bone formation around the implant. There were significant difference in the formation rate of newly bone between the two groups at different time(P < 0.05). Conclusion : PCI/HA group have excellent osteoconductivity and a good prospect of clinical application. |
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