鈦基植體表面網狀奈米多孔性結構對應力遮蔽效應之影響研究 Research of Stress Shielding Effect on Titanium-Based Alloy Implants with Multi-Nanostructure
中文摘要
諸多研究顯示，鈦基金屬及其合金於人體的生物相容性(biocompatibility)有 極高的評價，其非常適合做為人體的植入物，然而鈦金屬及其合金之所以具極 佳的生物相容性主要是與鈦金屬表面的氧化層有關，研究指出植體表面氧化層 厚度與孔徑大小對於細胞初始的攀附行為、增殖及分化有密切的關係。但因鈦金 屬植體表面之機械性質與原生骨組織仍有差異，導致植體植入後可能發生因應 力遮蔽效應所產生的骨質吸收問題。若能於植體表面氧化層製作奈米網狀多孔性 結構，除將有助於細胞攀附、增殖及分化外，亦可有效降低鈦植體表面之楊氏係 數，避免應力遮蔽效應發生，達到更趨完善的骨整合效應。於文獻指出多孔性氧 化層結構可有效降低鈦金屬表面之楊氏係數，因此，本研究以電化學陰極處理 方式使鈦基金屬表層形成一層氫化鈦(TiH2)薄膜，再以電化學陽極處理，使表 面形成一層網狀奈米多孔性的二氧化鈦(TiO2)結構，並以一些物理及化學性的 分析儀器測試表面之成分、元素、膜厚、孔洞大小及結構，進一步探討奈米網狀 多孔性的二氧化鈦的形成對鈦金屬表面楊氏係數及應力遮蔽效應的影響。
英文摘要
Metals are becoming increasingly popular as surgical implants in the cardiovascular, neurosurgery, maxillofacial, orthopedic and dental fields by many researches. They are due to their excellent
biocompatibility and mechanical properties. However, there is particular difference in the Young’s modulus between artificial implants and human bones. The difference of Young’s modulus will result in stress shielding effect, leading to early bone loss. As
mentioned above, the surface characteristics of the implant, such as pore sizes/roughness, oxide thickness are related to initial cell
behaviors and enhancing osseointegration. It can be good for osseointegration if the implant can effectively keep the oxidation layer with nanoporousity and increasing oxide thickness. Based on the present study, in order to gain the thick oxidation and the nanoporous structure, the titanium hydride is the main factor in forming thick nanoporous oxide layer. The present electrochemical process was performed as surface treatment of titanium-based implant. Titanium hydrides were formed on implant surface
following cathodic treatment. Nanoporous titanium oxide structure
was formed by anodic surface treatment. As the mentioned above, physical properties, chemical properties as well as biocompatibility of titanium implant with and without electrochemical treatments were analyzed clearly. Furthermore, effect of mechanical properties and stress shielding on nanoporous implant surface and bone were also investigated and discussed.
This research explores the effects of nano-(??-TiH, g-TiH2, and a- TiH1.971) phases on the formation of multi-nano-titania film by anodization with cathodic pretreatment. Nano-titanium hydrides and sub-stoichiometric nano-titanium hydrides were formed following cathodization. A multi-nanoporous titania film was formed on the titanium after anodization. The nano-hydrides are directly changed to multi-nanoporous titania film by a dissolution reaction after
anodization. Anodization with cathodic pretreatment not only yields a titanium surface with a multi-nanostructure, but also transforms the titanium surface into a nanostructured titania surface. Formation of nano-hydrides by cathodization and oxidation by anodization are believed to enhance biocompatibility and improve bone to interface contact (BIC), thereby accelerate the initial osseointegration and re- osseointegration.
