目的用荧光显微镜分析掺镁羟基磷灰石涂层对种植体骨结合的影响。方法将20个种植体分为2组,每组10个。一组为掺镁羟基磷灰石(magnesium-substituted hydroxyapatite,Mg-HA)涂层种植体;一组为纯羟基磷灰石(hydroxyapatite,HA)涂层种植体...目的用荧光显微镜分析掺镁羟基磷灰石涂层对种植体骨结合的影响。方法将20个种植体分为2组,每组10个。一组为掺镁羟基磷灰石(magnesium-substituted hydroxyapatite,Mg-HA)涂层种植体;一组为纯羟基磷灰石(hydroxyapatite,HA)涂层种植体。涂层均采用电化学沉积技术制备。种植体植入成年兔股骨内。在种植术后第7天给予盐酸土霉素;在术后第28天给予茜素氨羧络合剂;在术后第46天给予钙黄绿素。8周后取出股骨,制备硬组织切片,然后行荧光显微观察,分析两组种植体表面的骨沉积率(bone mineral apposition rate,MAR)、骨面积率(bone area ratio,BAR)、骨接触率(bone to implant contact,BIC)是否存在差异。结果荧光显微观察显示两组种植体周围均有广泛新骨形成。种植术后第7天至53天,Mg-HA组的MAR、BAR大于HA组,但两者间无显著差异(P>0.05)。术后第7天和第28天,Mg-HA组的BIC大于HA组,两者间有显著差异(P<0.05)。结论与HA涂层相比,Mg-HA涂层可促进种植体的早期骨结合。展开更多
Recently,magnesium and its alloys have attracted more and more attention as promising implant materials due to their excellent properties such as good biocompatibility,biodegradation,non-toxicity and comparable mechan...Recently,magnesium and its alloys have attracted more and more attention as promising implant materials due to their excellent properties such as good biocompatibility,biodegradation,non-toxicity and comparable mechanical properties with natural bone.They can be gradually degraded and absorbed so as to avoid the second surgery for implants removal after the tissues are healed completely.In addition,they are also able to prevent the stress shielding effect in human body environment because of the density,elastic modulus and yield strength of magnesium closer to the bone.Unfortunately,the high corrosion rate which causes early mechanical failure of the implants in physiological environment limits the widespread use of magnesium alloys for clinical application in biology.And the high corrosion process usually causes huge hydrogen evolution and alkalinization,resulting in problems against the implants as well as the surrounding tissues.In order to enhance the corrosion resistance of magnesium alloys,in this study,the ZEK100 magnesium alloy was pre-deformed with a highpressure torsion(HPT)process and then fabricated hydroxyapatite(HA)coatings with different contents of Mg(OH)2 nanopowder via hydrothermal method.The specimens were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).At the same time,prior and after the HPT procedure,the metallography,microhardness and tensile tests of specimens were characterized.Meanwhile,the corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy(EIS)and hydrogen evolution tests.And the interface bonding strength of the HA coating on the magnesium alloy substrate was evaluated by a tape adhesion test/scratch test.Results showed that HPT processing refined the grain size and introduced a great number of twins,resulting in the enhancement of microhardness and Young’s modulus of ZEK100 magnesium alloy,but hardness values at the edge were higher than those at the center due to the uneven shear strain.At the same conditions,the HA coating on HPT-ZEK was denser,thicker than that on ZEK sample and the crystal sizes of HA were smaller on HPT-ZEK.These were attributed to fine,uniform distributed secondary phases and lots of fine grains,twins,grain boundaries in HPT-ZEK substrates which can provide more nucleation sites for the HA crystal.In terms of the amount of Mg(OH)2 nanopowder,Mg(OH)2 nanopowder significantly influenced the microstructure and thickness of the HA coating.And at a 0.3 mg/mL content of Mg(OH)2 nanopowder,there was the densest,thickest HA coating on magnesium alloys,and the crystal size of HA was minimum.Specifically,the HA coating thickness on ZEK-03(0.3 mg/mL Mg(OH)2 nanopowder)was 1.8 times of that on ZEK-00(0 mg/mL Mg(OH)2 nanopowder),while the HA coating thickness on HPT-03 was 2.6 times of that on ZEK-00.And the adhesion strength of HA coating on HPT-03 substrate was better than that on ZEK-03.In addition,HPT technology and surface modification by HA coating simultaneously increased the corrosion resistance of ZEK100 magnesium alloy and the corrosion of HPT-ZEK samples occurred in a more uniform manner,while it was pitting on the surface of ZEK100 magnesium alloy.Therefore,there was the best corrosion resistance on HPT-03 sample,which could promote the application of magnesium alloys in biomedical fields.展开更多
文摘目的用荧光显微镜分析掺镁羟基磷灰石涂层对种植体骨结合的影响。方法将20个种植体分为2组,每组10个。一组为掺镁羟基磷灰石(magnesium-substituted hydroxyapatite,Mg-HA)涂层种植体;一组为纯羟基磷灰石(hydroxyapatite,HA)涂层种植体。涂层均采用电化学沉积技术制备。种植体植入成年兔股骨内。在种植术后第7天给予盐酸土霉素;在术后第28天给予茜素氨羧络合剂;在术后第46天给予钙黄绿素。8周后取出股骨,制备硬组织切片,然后行荧光显微观察,分析两组种植体表面的骨沉积率(bone mineral apposition rate,MAR)、骨面积率(bone area ratio,BAR)、骨接触率(bone to implant contact,BIC)是否存在差异。结果荧光显微观察显示两组种植体周围均有广泛新骨形成。种植术后第7天至53天,Mg-HA组的MAR、BAR大于HA组,但两者间无显著差异(P>0.05)。术后第7天和第28天,Mg-HA组的BIC大于HA组,两者间有显著差异(P<0.05)。结论与HA涂层相比,Mg-HA涂层可促进种植体的早期骨结合。
基金sponsored by the National Natural Science Foundation of China ( 51571150,11572222)Tianjin Natural Science Foundation ( 14JCYBJC16900)
文摘Recently,magnesium and its alloys have attracted more and more attention as promising implant materials due to their excellent properties such as good biocompatibility,biodegradation,non-toxicity and comparable mechanical properties with natural bone.They can be gradually degraded and absorbed so as to avoid the second surgery for implants removal after the tissues are healed completely.In addition,they are also able to prevent the stress shielding effect in human body environment because of the density,elastic modulus and yield strength of magnesium closer to the bone.Unfortunately,the high corrosion rate which causes early mechanical failure of the implants in physiological environment limits the widespread use of magnesium alloys for clinical application in biology.And the high corrosion process usually causes huge hydrogen evolution and alkalinization,resulting in problems against the implants as well as the surrounding tissues.In order to enhance the corrosion resistance of magnesium alloys,in this study,the ZEK100 magnesium alloy was pre-deformed with a highpressure torsion(HPT)process and then fabricated hydroxyapatite(HA)coatings with different contents of Mg(OH)2 nanopowder via hydrothermal method.The specimens were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).At the same time,prior and after the HPT procedure,the metallography,microhardness and tensile tests of specimens were characterized.Meanwhile,the corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy(EIS)and hydrogen evolution tests.And the interface bonding strength of the HA coating on the magnesium alloy substrate was evaluated by a tape adhesion test/scratch test.Results showed that HPT processing refined the grain size and introduced a great number of twins,resulting in the enhancement of microhardness and Young’s modulus of ZEK100 magnesium alloy,but hardness values at the edge were higher than those at the center due to the uneven shear strain.At the same conditions,the HA coating on HPT-ZEK was denser,thicker than that on ZEK sample and the crystal sizes of HA were smaller on HPT-ZEK.These were attributed to fine,uniform distributed secondary phases and lots of fine grains,twins,grain boundaries in HPT-ZEK substrates which can provide more nucleation sites for the HA crystal.In terms of the amount of Mg(OH)2 nanopowder,Mg(OH)2 nanopowder significantly influenced the microstructure and thickness of the HA coating.And at a 0.3 mg/mL content of Mg(OH)2 nanopowder,there was the densest,thickest HA coating on magnesium alloys,and the crystal size of HA was minimum.Specifically,the HA coating thickness on ZEK-03(0.3 mg/mL Mg(OH)2 nanopowder)was 1.8 times of that on ZEK-00(0 mg/mL Mg(OH)2 nanopowder),while the HA coating thickness on HPT-03 was 2.6 times of that on ZEK-00.And the adhesion strength of HA coating on HPT-03 substrate was better than that on ZEK-03.In addition,HPT technology and surface modification by HA coating simultaneously increased the corrosion resistance of ZEK100 magnesium alloy and the corrosion of HPT-ZEK samples occurred in a more uniform manner,while it was pitting on the surface of ZEK100 magnesium alloy.Therefore,there was the best corrosion resistance on HPT-03 sample,which could promote the application of magnesium alloys in biomedical fields.
