RESUMO
Objective To observe the research of the biologically performance,interface micro-structure and nano-indentation situation when polymethyl methacrylate bone cement-PMMA injected into rabbit in the near future and far future individually.Methods New Zealand white rabbits were used ovariectomy plus dcxamethasone intramuscular injection to establish osteoporosis animal model.All animal models were divided into 3 groups with 35 in each osteoporosis group,testing group,and normal group.Execute the lumbar centrum of New Zealand rabbit as osteoporosis bone defect model,injected bone cement,with the help of material dynamo experiment machine to do the axial compression tests,three point bending test,and torsion test in order to observe the biological dynamic changes.Optical microscope,fluorescence microscope and scanning electron microscope were used to observe the changes of micro bone cement and the changes of bone looseness.Nano-indentation testing was applied by the triboindenter to study the critical load.Results PMMA can rapidly establish the strong support with stable function in the near future.Biomechanical experiments showed that biomechanical properties of bone cement group was significantly higher than those in the other two groups.Biomechanical properties of bone cement group may decline with the time,but which were still better than those of OP in the control group.Histo-morphological observation result shows that under osteoporosis state the bone grows slower,bone's rebuilding time also extended.And in the later period,main bone's continuous osteoporosis had some impact on the interface.Nano-indentation testing showed that the young modulus and stiffness of the interface among bone,material and interface were significantly differences.Bone cement had showen the best nano indentation hardness,then was interface and bone tissue.Conclusion The polymethyl methacrylate bone cement llⅢ has a good effect in filling,on account of it has great plasticity and liquidity and can penetrate into the minuteness aperture between trabecula,then after solidifying,it will combine firmly with the host bone.PMMA can rapidly establish the strong support with stable function after operation.The performance is decreasing in the far future but still with satisfaction.