锶磷灰石涂层钛种植体骨结合的动物实验

目的 观察微弧氧化锶磷灰石(strontium-substituted hydroxyapatite,Sr-HA)涂层钛种植体的成骨活性,探讨锶元素掺入羟基磷灰石(hydroxyapatite,HA)涂层后对骨结合的影响.方法 分别对实验组(Sr-HA涂层种植体)和对照组(HA涂层种植体)的表面形貌进行扫描电镜观察,并采用X线衍射仪分析膜层相组成.将两组种植体各12枚植入新西兰兔双侧股骨髁下外侧、胫骨结节处,术后对实验动物进行多荧光序列标记,饲养4周和12周取材,采用组织学观察、种植-骨界面线扫描分析评价涂层的骨结合能力.结果 种植体微弧氧化膜层均呈现多级孔洞状结构;X射线衍射分析显示,锶元素的掺入引起HA的衍射峰向小角度方向偏移,晶格间距增大,稳定性下降;多荧光序列标记显示,Sr-HA涂层早期即表现出成骨活性,实验组骨矿化沉积率(4.75±0.46)μm/d]显著高于对照组(3.21±0.44)μm/d];组织染色及能谱分析显示,骨种植界面上有生物类骨磷灰石层形成,12周时该磷灰石层转化为成熟的骨组织并与涂层形成紧密的骨结合.结论 锶元素的掺入可提高Sr-HA涂层的生物学活性,加速其表面生物类骨磷灰石层的形成,增强膜层的成骨能力,促进膜层与骨组织的结合.

Improvement of osseointegration of titanium dental implant surfaces modified with strontium-substituted hydroxyapatite

Objective To explore the osteogenic activity of a micro-arc oxidation (MAO)-treated strontium (St)-substituted hydroxyapatite (St-HA) coating developed to enhance the osseointegration of titanium dental implants, and to investigate the strengthening mechanisms of bone bonding of crystalline hydroxyapatite(HA) with incorporation of strontium in vivo. Methods The morphology and phase component of the oxidized film of Sr-HA and HA coated implants were examined by SEM and X-raydiffraction(XRD). Then, twenty-four imlpants were inserted into the metaphysis of rabbits tibias and femurs using polyfluorochrome sequential labeling. Four and 12 weeks following the surgery, the morphology and chemical composition of the bone-implant interfaces were evaluated by histological examination and energy-dispersive X-ray. Results The XRD patterns showed that diffraction peaks of HA shift to lower 20 values with Sr-addition, which resulted in decreases in lattice energy and then erystallinity. St-HA coating presented a microporous structure in the SEM observation. Meanwhile, Sr-HA coating exhibited osteogenic activity at the early stage of bone healing period and new bone mineral apposition ratio (4. 75 ±0.46) μm/d]was significantly higher than that of the control group(3.21 +0.44) μm/d]. An apatite layer was observed at the interface of bone-Sr-HA coating in light microscopy observation and energy-dispersive X-ray analysis. Then the apatite layer was precipitated and formed new bone which became mature bone and bonded tightly to the Sr-HA. Conclusions Strontium-substituted hydroxyapatite coating shows high biological activity, which can accelerate the formation of apatite layer, hence the osteogenic ability.