本研究的目的是設計出具有良好骨整合能力的人工牙根植體表面，透過表面改質的方式可以進一步改善骨整合能力。目前人工硬組織植體固定的方式除了藉由形狀的設計來達到生物式的固定之外，同時也藉由表面處理技術改質成具有生物活性的表面。鈦金屬因具有良好生物親和性、耐腐蝕特性及機械性質，被廣泛應用於牙科及骨科植入物。因此許多學者研究的主軸為如何利用最佳表面處理方式來改善植入物植入初期骨癒合速度與長期骨組織的鍵結強度。然而製備奈米結構有許多方法，其中陽極氧化處理由於可以製備出奈米級的點與孔洞、且容易控制孔洞特徵、自我組織化的特性等，是目前最常被採用來製備奈米結構的方法。然而二氧化鈦奈米管本身因機械強度不足，容易在受力條件下引起剝落的現象，造成異物反應發生。本研究針對此問題，進行新型規則奈米管陣列研究，希望可以保留奈米結構同時提升奈米管陣列的機械性質，並藉由生物功能性修飾來改善碳化鈦奈米管之生物親和性。
整體研究的目的為利用陽極氧化(anodized titanium oxide, ATO)在鈦基材上製備出二氧化鈦奈米管陣列，並利用真空熱處理方式(vacuum heat treatment, VHT)將碳原子置換掉氧原子來獲得碳化鈦奈米管，接續分別利用低溫射頻氧電漿處理技術(RF oxygen plasma treatment)及自組裝單分子膜技術(self-assembled monolayers, SAMs)來進行表面化學性改質以獲得特殊表面，預期可以改善碳化鈦奈米管之生物親和性。在材料性質方面，利用掃描式電子顯微鏡 (SEM)觀察試片表面型態；能量散射光譜 (EDS)分析表面化學元素組成；薄膜X光繞射儀 (TF-XRD)鑑定表面結晶相組成；聚焦離子束 (FIB)及穿透式電子顯微鏡 (TEM)觀察試片橫截面型態及材料內部型態、晶體原子結構；接觸角(Contact angle)量測法分析試片之親疏水性；奈米壓痕試驗儀 (Nanoindentation)量測機械性質的變化；傅立葉紅外線光譜 (FT-IR)、化學分析電子能譜儀 (XPS)分析表面官能基鍵結組成；在細胞生理反應方面，培養細胞於試片表面，評估碳化鈦結構之奈米管在接上單分子膜後對細胞增生之影響，並使用SEM觀察細胞培養於樣品之表面型態。預期碳化鈦奈米管之機械性質可大幅增加，且碳化鈦本身屬於化學穩定性，鈦及碳亦為生物相容性良好之元素，應用於植體植入後可與周圍骨組織形成骨整合固定之效果，並藉由單分子膜進行表面生物功能性修飾，期望藉由單分子膜結構之末端官能基能促進與調控細胞增生之能力，具有進一步研究的潛力。
結果表明，我們透過真空熱處理的技術成功將二氧化鈦奈米管轉化為碳化鈦奈米管。同時，碳化鈦奈米管不僅可保持管狀的奈米管結構，還具有比二氧化鈦奈米管更佳的機械性能。藉由SEM及FIB可清楚觀察到碳化鈦奈米管的表面型態及橫截面形態。此外，在體外試驗中，由SEM及MTT分析得到的結果表明在所有組別中，碳化鈦奈米管具有最快的細胞增殖速率和最佳的細胞形態表現。然而，具有不同末端功能性官能基團改質之組別在細胞性能方面略優於TiO2奈米管組別。總結，我們展現了具有碳化鈦奈米管層的鈦金屬植入物的製備過程及特性分析，其具有良好的機械性質與對成骨細胞的生物相容性。藉由這些優點，新型的碳化鈦（TiC）奈米管結構可應用於牙科植入物領域之中。

The aim of this study was to develop and design an intelligently designed dental implant surface with good osseointegration. Recently, the idea of improved dental implant fixation has come from shape design to expand the contact area between bone and implant surface to enhance osseointegration. Many researchers usually paid attention to get the best method to improve the short term bone healing rate and long term biological fixation. Titanium and its alloys are widely used in dental and orthopedic implants because of their favorable biocompatibility, high corrosion resistance and excellent mechanical properties. Recently, researchers have simultaneously studied the effects of nanostructure especial in ordered nanostructure on biocompatibility. However, among many surface modification methods, anodic oxidation could produce the ordered arrangement of pores and tubes by a self-organized process, the pore size and its distribution could be easily controlled by this method. Therefore, this study used this method to form titanium oxide (TiO2) nanotube arrays on titanium substrate. However, the weak mechanical properties of titanium oxide would prohibit the clinical application in loading condition. We know that one of the most important materials in medical and dental applications is their mechanical properties. This is important in bone and implant materials where long term in vivo structural stability is the most important.
In order to solve this problem, high strength of titanium carbide (TiC) nanotube arrays on titanium substrate were prepared in this study. We expect that the mechanical properties of titanium carbide nanotubes could be served as artificial implant in clinical condition. In addition, the nanostructure could modulate cell responses such as adhesion, proliferation and differentiation. But the biological responses of titanium carbide nanotubes may need to be modified. In this investigation, anodization treatment will be used to grow highly ordered titanium oxide nanotubes. Then, post vacuum heat treatment would replace oxygen by carbon in controlled environment. After heat treatment, biocompatibility could be achieved by RF-O2 plasma treatment and self-assembled monolayers (SAMs) technique. The surface morphology of the specimen was observed by SEM, with an EDS for chemical analysis. The phase composition was identified by TF-XRD. The cross-section and crystal structure were analyzed by FIB and TEM. The wettability was evaluated by contact angle test. Nanoindentation was used to measure the mechanical properties. The surface chemistry of the specimen was analyzed by FT-IR and XPS. In vitro test was used to investigate the cell morphology and proliferation.
The results show that we successfully converted the titanium oxide nanotubes into titanium carbide nanotubes by vacuum heat treatment. At the same time, results show that titanium carbide nanotubes could not only maintain the tubular structure but also have better mechanical properties than titanium oxide nanotubes. The surface and cross-sectional morphology of titanium carbide nanotubes could be clearly observed by SEM and FIB. Additionally, in vitro test, the results obtained from SEM and MTT analysis suggested that the titanium carbide nanotubes have the fastest cell proliferation rate and the best cell performance of all groups. However, groups with various terminal functional monolayers are slightly better than the TiO2 group in cell performance. Finally, we demonstrate the preparation and characteristics of titanium implant with titanium carbide nanotubes coating that have good mechanical properties and biocompatibility for human osteoblasts. With these advantage, the novel titanium carbide (TiC) nanotube structure can be used in the field of dental implants.

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