Characteristics of metals used in implants
Characteristics of metals used in implants
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DOI：
10.1089/end.1997.11.383
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发表时间：
1997-12-01
影响因子：
2.7
通讯作者：
Gotman, I
中科院分区：
文献类型：
--
作者：
Gotman, I
人体内任何材料的性能都由两组特性控制：生物功能性和生物相容性。在20世纪90年代中期，随着材料的广泛使用，相对容易满足可植入装置的机械和物理功能性的要求。因此，用于医疗应用的材料的选择通常基于生物相容性的考虑，当考虑金属和合金时，材料对腐蚀的敏感性和腐蚀对组织的影响是生物相容性的中心方面。目前使用的316L不锈钢、钴铬和钛基植入物合金的耐腐蚀性依赖于它们通过薄的表面氧化物层的钝化，不锈钢的耐腐蚀性最差，仅用于临时植入物，钛和钴铬合金在体内不会腐蚀;然而，金属离子缓慢地扩散通过氧化物层并在组织中积累。当将金属植入物置于人体中时，它被一层纤维组织包围，其厚度与溶解产物的量和毒性以及植入物和相邻组织之间的运动量成比例。纯钛在某些条件下可能引起最小的纤维包裹，尽管在使用不锈钢植入物时会遇到多达2 mm厚的纤维层的增殖，但是上级抗断裂性和抗疲劳性使得金属成为传统承重应用的选择材料。在该综述中，关于支架应用讨论了目前使用的金属和合金的功能性，此外，描述了镍钛诺（一种被考虑用于制造泌尿系统支架的合金）的“形状记忆”和“伪弹性”特性。
The performance of any material in the human body is controlled by two sets of characteristics: biofunctionality and biocompatibility, With the wide range of materials available in the mid-1990s, it is relatively easy to satisfy the requirements for mechanical and physical functionality of implantable devices, Therefore, the selection of materials for medical applications is usually based on considerations of biocompatibility, When metals and alloys are considered, the susceptibility of the material to corrosion and the effect the corrosion has on the tissue are the central aspects of biocompatibility, Corrosion resistance of the currently used 316L stainless steel, cobalt-chromium, and titanium-based implant alloys relies on their passivation by a thin surface layer of oxide, Stainless steel is the least corrosion resistant, and it is used for temporary implants only, The titanium and Co-Cr alloys do not corrode in the body; however, metal ions slowly diffuse through the oxide layer and accumulate in the tissue, When a metal implant is placed in the human body, it becomes surrounded by a layer of fibrous tissue of a thickness that is proportional to the amount and toxicity of the dissolution products and to the amount of motion between the implant and the adjacent tissues, Pure titanium may elicit a minimal fibrous encapsulation under some conditions, whereas the proliferation of a fibrous layer as much as 2 mm thick is encountered with the use of stainless steel implants, Superior fracture and fatigue resistance have made metals the materials of choice for traditional load-bearing applications, In this review, the functionality of currently used metals and alloys is discussed with respect to stenting applications, In addition, the "shape memory" and "pseudo-elasticity" properties of Nitinol--an alloy that is being considered for the manufacturing of urologic stents--are described.