牙科植體用新型氫氧基磷灰石/鈦複合漸層之性質

氫氧基磷灰石鍍層己經使用在承載負荷的硬組織植體應用上。本研究利用電漿噴鍍技術製造功能性HA/Ti漸層在Ti6Al4V基材上，以改善鍍層-基材界面特性。這種漸層方式是採用底層為Ti鍵結層，表層為HA層，中間則是HA/Ti混合層，混合層是以改變Ti和HA粉末的輸入速率和粉量，將Ti含量隨著厚度增加而減少。在本論文中，將探討HA/Ti漸層及其經過後續熱處理，對其抗腐蝕性、塗層-基材之界面穩定性、與鍵結強度有何影響。實驗的結果指出功能性漸層的表面化學性質和形態跟純HA鍍層相似。但漸層的鍵結強度則較優於HA單層。疲勞循環測試發現HA鍍層鍵結強度顯著下降23%，然而在一百萬次的循環載荷下的HA/Ti漸層並沒有明顯的強度減少。適當的熱處理讓漸層的非晶質磷酸鈣結晶化。在模擬體液下電化學測量的結果也指出在疲勞測試後，漸層比單獨HA鍍層有較好的性質。經熱處理後抗腐蝕性提高。經600oC熱處理，不但能夠增加結晶性和降低鍍層缺陷，而且增加鍵結強度，噴鍍後熱處理可提升HA/Ti漸層品質。

關鍵字

氫氧基磷灰石；鈦；電漿噴鍍；鍍層；植體

並列摘要

Hydroxyapatite coating have been used as load-bearing implant applications. The aim of this work is to deposit functionally graded HA/Ti layers using plasma spray to improve the coating-substrate interface properties. In addition to the Ti bondcoat and the top HA biolayer, the alternating layers were created by means of changing the feeding rate and input powder of Ti and HA. The stability of the graded coatings such as corrosion resistance and fatigue, and bonding strength of the potential graded coatings without and with post-deposition heat treatment were examined. Results showed that surface chemistry and morphology of the graded coatings were similar to those of monolithic HA coatings. The bonding strength values of the as-sprayed graded coating were much superior to those of monolithic HA coatings. The cyclic fatigue did have a statistically significant effect on bond strength of monolithic HA coatings, with a decrease of 23%. However, the graded coatings were able to survive 1 million cycles of loading in air without significantly reduced bond strength. The in vitro electrochemical measurement results also indicated that the graded coatings had a more beneficial and desired behavior than monolithic HA coatings after fatigue. An appropriate heat treatment resulted in recrystallization of amorphous calcium phosphate of as-sprayed coatings. The enhancement of the resistance to corrosion took place after heat treatment. Consequently, we concluded that the heat treatment at 600℃, endowing with increased crystallinity and the reduced defects as well as enhanced bond strength, may be a suitable post-deposition treatment method to promote the characteristics of graded HA/Ti coatings.

並列關鍵字

hydroxyapatite ； titanium ； plasma spray ； coating ； implant

參考文獻

1. M. Jarcho, "Calcium phosphate ceramics as hard tissue prosthetics", Clin. Orthop., 157:259-278, 1981.

2. L. L. Hench, "Bioceramics: from concept to Clinic", J. Am. Ceram. Soc., 74:1487-1510, 1991.

3. P.-I. Branemark, B. O. Hansson, R. Adell, U. Breine, J. Lindstrom, O. Hallen, and A. Ohman, "Osseointegrated implants in the treatment of the endentulous jaw", Scand. J. Plast. Reconstruc. Surg., 11:16, 1977.

4. T. Albrektsson, P.-I. Branemark, H.-A. Hansson, and J. Lindstrom, "Osseo-integrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man", Acta Orthop. Scand., 52:155-170, 1981.

5. C. Johansson, J. Lausmaa, M. Ask, H-A. Hansson, and T. Albrektsson, "Ultra-structural differences of the interface zone between bone and Ti6A14V or commercially pure titanium", J. Biomed. Eng., 11:3-8, 1989.

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牙科植體用新型氫氧基磷灰石/鈦複合漸層之性質

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