Research of Stress Shielding Effect on Titanium-Based Alloy Implants with Multi-Nanostructure

• Main Authors: Chia-Pin Chang, 張家賓
• Other Authors: 歐耿良
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/50951935997066522468

碩士 === 臺北醫學大學 === 口腔科學研究所 === 95 === 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.