Kim Seong Ryoung, Lee Keon Mo, Kim Jin Hong, Choi Young Jin, Park Han Ick, Jung Hwa Chul, Roh Hyung Jin, Han Jee Hye Lo, Kim Joon Rae, Lee Bu-Kyu
Department of Oral and Maxillofacial Surgery, Yonsei University Dental Hospital, Seoul, Republic of Korea.
Department of Oral and Maxillofacial Surgery, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Republic of Korea.
Biomater Res. 2022 Jul 6;26(1):29. doi: 10.1186/s40824-022-00279-1.
Magnesium alloys have been receiving much attention for use in biodegradable metal implants because of their excellent mechanical properties and biocompatibility. However, their rapid breakdown and low bioactivity can cause the implant to lose mechanical integrity before the bone is completely healed. Moreover, hydrogen gas released during degradation can significantly delay the tissue regeneration process. To solve the instability of magnesium alloys, Zn and Ca can be added to improve the mechanical properties and biocompatibility. One other way to improve the mechanical properties of Mg is plasma electrolytic oxidation (PEO), which provides a dense, thick ceramic-like coating on the Mg surface. In this study, high-purity Mg was selected as the control, and Mg-1wt%Zn-0.1wt%Ca alloy and PEO-treated Mg-1wt%Zn-0.1wt%Ca alloy were selected as the test materials; the results of radiographic and histological analyses of their biocompatibility are reported herein.
Nineteen New Zealand white rabbits were used in the study. Rod-bars (Ø2.7 × 13.6 mm) were placed on both paravertebral muscles, and cannulated screws (Ø2.7x10mm) were placed on both femur condyle notches. Each animal was implanted in all four sites. X-rays were taken at 0, 2, 4, 8, and 12 weeks, micro-CT, and live-CT were taken at 4, 8, and 12 weeks. At weeks 4, 8, and 12, individuals representing each group were selected and sacrificed to prepare specimens for histopathological examination.
The results confirm that in vivo, Mg-1wt%Zn-0.1wt%Ca alloy had higher corrosion resistance than high-purity Mg and safely degraded over time without causing possible side effects (foreign body or inflammatory reactions, etc.). In addition, PEO treatment of Mg-1wt%Zn-0.1wt%Ca alloy had a positive effect on fracture recovery by increasing the bonding area with bone.
Our results suggest that PEO treatment of Mg-1wt%Zn-0.1wt%Ca alloy can be a promising biomaterials in the field of various clinical situations such as orthopedic and maxillofacial surgerys.
镁合金因其优异的机械性能和生物相容性，在可生物降解金属植入物领域备受关注。然而，它们的快速降解和低生物活性会导致植入物在骨骼完全愈合之前失去机械完整性。此外，降解过程中释放的氢气会显著延迟组织再生过程。为了解决镁合金的不稳定性，可以添加锌和钙来改善其机械性能和生物相容性。另一种改善镁机械性能的方法是等离子体电解氧化（PEO），它能在镁表面形成一层致密、厚实的类陶瓷涂层。在本研究中，选择高纯度镁作为对照，选择Mg-1wt%Zn-0.1wt%Ca合金和经PEO处理的Mg-1wt%Zn-0.1wt%Ca合金作为测试材料；本文报告了它们生物相容性的影像学和组织学分析结果。
本研究使用了19只新西兰白兔。将棒条（Ø2.7×13.6毫米）置于双侧椎旁肌肉上，将空心螺钉（Ø2.7x10毫米）置于双侧股骨髁切迹处。每只动物在所有四个部位都进行了植入。在0、2、4、8和12周时拍摄X射线，在4、8和12周时进行微型CT和活体CT检查。在第4、8和12周时，选择每组的代表个体进行处死，以制备用于组织病理学检查的标本。
结果证实，在体内，Mg-1wt%Zn-0.1wt%Ca合金比高纯度镁具有更高的耐腐蚀性，并且随着时间的推移安全降解，不会引起可能的副作用（异物或炎症反应等）。此外，对Mg-1wt%Zn-0.1wt%Ca合金进行PEO处理通过增加与骨的结合面积对骨折恢复有积极影响。
我们的结果表明，对Mg-1wt%Zn-0.1wt%Ca合金进行PEO处理在骨科和颌面外科等各种临床情况下可能是一种有前景的生物材料。
