牙科用多孔Ti-Nb-Sn合金特性及生物活性之研究

Characteristics and Bioactivity of the Porous Ti-Nb-Sn Alloy for Dental Applications

劉子瑄(TZU-HSUAN LIU)

指導教授 ： 許學全

中臺科技大學/健康科學院/牙體技術暨材料系碩士班/碩士(2017年)

摘要

新型Ti-Nb-Sn合金具有良好的生物相容性、耐腐蝕性及低彈性模數，本研究期望製作成多孔結構以更適合用於牙科植入物。實驗以粉末冶金方法，將Ti、Nb、Sn粉末依比例配製成Ti-Nb-Sn合金，分別添加50、60、70 vol.% 碳酸氫銨作為成孔劑，壓製圓柱狀試片尺寸直徑7、高11 mm試片用於機械性質測試，直徑7、高2 mm試片用於生物活性評估。試片燒結分兩步驟，先以175 ℃ 2小時，之後於1100 ℃ 15小時。結果以SEM觀察分析顯示，多孔Ti-Nb-Sn合金的孔徑為0.5 - 750 μm，。孔隙率為50.69 - 67.00％，抗壓強度為110.03 - 27.01 MPa，彈性模數為6.37 - 0.　52 GPa。之後以添加　50 % 成孔劑之試片進行不同濃度鹼熱處理，結果顯示多孔合金表面形成鈦酸鈉層的網狀結構，其中選擇以1M NaOH處理之試片進行生物活性評估，發現當浸泡SBF溶液4天後，合金表面上已覆蓋一層緻密的磷灰石層，表現良好之生物活性。TNS50試片與MG-63共培養第七天後，鹼熱處理的多孔試片所呈現的O.D. 值最高，並與螢光顯微鏡結果顯示，細胞呈攤平且偽足有伸展的情形，表示多孔結構有利於細胞生長，且鹼熱處理過後對細胞是有更適當的環境 。本研究製作的多孔Ti-Nb-Sn合金顯示與自然骨相似的抗壓強度和彈性模數且孔徑範圍適合骨細胞生長，將來可發展作為很好的骨替代材料。

關鍵字

多孔鈦合金 ； 粉末冶金 ； 鹼熱處理 ； 生物相容性

並列摘要

The new titanium alloy Ti-Nb-Sn contains Nb and Sn elements, which means the material has good biocompatibility, corrosion resistance, and a low modulus of elasticity. However, the mismatch of Young’s modulus between Ti alloys and bone could lead to bone resorption and the loosening of the implant. In this study, the researchers have fabricated a porous Ti-Nb-Sn alloy that solves these problems, making it suitable for use in bone implants.
Commercial elemental metal powders of Ti, Nb, and Sn were weighed to form a composition of Ti-Nb-Sn. The powders were mixed with a polyvinyl alcohol (PVA) binder, and then with 50 vol.%, 60 vol.%, and 70 vol.% of ammonium hydrogen carbonate (NH4HCO3) (referred to as TNS50, TNS60 and TNS70). Ti-Nb-Sn alloy samples with two different heights and a diameter of 7 mm were prepared: one was a height of 11 mm for mechanical testing and the other was a height of 2 mm for biological activity testing. The sintering process was divided into two steps: sintering at 175°C for 2 hours and then 1100°C for 15 hours. SEM observations found that the pore size of the porous Ti-Nb-Sn alloy samples was in the range of 0.5–750 μm, with a porosity of 50.69–67.00 %, a compressive strength of 110.03–27.01 MPa, and an elastic modulus of 6.37–0.52 GPa. A micro-reticular structure formed on the surface of the samples after they were immersed in different concentrations of 1 M, 3 M, and 5 M NaOH solutions at 60°C. The porous Ti-Nb-Sn treated in 1 M NaOH solution (referred to as TNS50-1M) showed the highest compressive strength when compared with TNS50-3M and TNS50-5M, which is a satisfactory match with cortical bone. Thus, the TNS50-1M specimen was selected for the bioactivity and biocompatibility tests. During the bioactivity tests, the surface of the TNS50-1M sample was covered in a denser apatite layer than what was found on TNS50 after immersion in SBF solution for 4 days. In terms of biocompatibility, TNS50-1M demonstrated higher cell activity and more cell growth than that found on TNS50.
In summary, the TNS50-1M has a compressive strength and elastic modulus similar to that of natural bone and a pore size necessary for osteoblast growth, making it a good candidate for a bone substitution material.

並列關鍵字

Porous titanium alloy ； powder metallurgy ； alkali-heat treatment ； biocompatibility

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