基于SLM技术的表面多孔钛金属多根牙种植体的骨结合研究

Osseointegration of Multi-Roots Ti6Al4V Implant with Porous Surface Based on SLM Technology

为研制具有良好骨结合特性的多根牙种植体表面结构,利用有限元方法优化设计一种三维连通多孔结构,采用选择性激光熔化(SLM)3D打印技术实现了钛金属多根牙种植体及其表面三维连通多孔结构的制造。采用市售可吸收介质喷砂(RBM)表面处理的种植体作为对照组,在18只新西兰大白兔后肢胫骨上做同体对照植入实验,并分别于术后4、8、12周获取种植体-骨组织标本。通过微CT扫描标本,统计分析实验组和对照组的BV/TV值;同时制作硬组织切片,甲苯胺蓝染色观察种植体周围骨形成的情况。实验结果显示:4周时可见实验组的BV/TV已高于对照组,12周时BV/TV值显著高于对照组(P<0.05),最高值达到47.83%。由拟合的曲线可见实验组的新增骨量在12周后的增长趋势强于对照组。硬组织切片观察发现,4周时骨组织开始长入至种植体表面孔隙中,8周时双根分叉区域内可以观察到骨组织。同期对照可见新增骨组织的致密性也高于对照组。结果表明:采用SLM3D打印技术加工的、表面具有三维连通多孔结构的多根牙种植体成骨效能优于市售RBM表面处理的种植体,具有临床应用前景。

The present study was to develop a multi-roots dental implant （MRI） surface structure with fine osseointegration characteristics. Finite element method （FEM） was used to optimize a kind of connected pore structure; selective laser melting （SLM） technology was utilized to manufacture the MRIs. Eighteen New Zealand white rabbits were used in this study. Eighteen MRIs and 1g commercial implants with resorble blast media （RBM） treated surface were inserted into the left and right hind limb at proximal tibias. At the time point of 4, 8 and 12 weeks the rabbits were sacrificed and bone tissues with implant were collected. All specimens were scanned by micro-CT and then BV/TV values of two groups were obtained. After that the specimens were processed for undecalcified ground sectioning and stained by toluidine blue to observe bone formation around implant. The BV/TV value of experimental group was higher than the control group at the end of 4 weeks, and at the end of 12 weeks the value was significantly higher than control group （P 〈 0.05） , the peak value was elevated up to 47.83%. From the fitting curve of BV/TV value, bone mass around at MRIs were still increasing at the end of 12 weeks, while the control group had achieved a balance. Histological evaluations revealed that bone surround the MRIs were denser than those of RBM implants. At the end of 4 weeks bone tissue had grew into pore structures, and at the end of 8 weeks bone tissue were observed in the rootbifurcating area. In conclusion, the multi-roots dental implant with three-dimensional connected pore structure surface manufactured by SLM technology enhance its initial stability, which is of great clinical value owe to its better osteogenic characteristics.