鋅含量對介穩水泥的材料性質和生物相容性及生物活性之影響

牙科的治療日新月異，其目的都是想要保持牙齒的健康。在根管治療中，根尖手術和逆充填、根管破損修補、活髓治療，這幾項難題的是我們所要面對的問題中，十分棘手的病症。隨著生醫材料的發展，這些問題有逐漸獲得改善。 Mineral trioxide aggregate (MTA)因具有生物相容性、生物活性、封閉性質佳等優點，受到牙科醫師的推崇和喜愛。但是 MTA 硬化時間過長、操作性質不佳與可能含有有毒重金屬等問題卻是臨床應用的重大缺點。許多研究顯示 MTA 良好的生物相容性、生物活性以及封閉能力，主要是因為它是鈣矽生醫陶瓷的關係，同樣的問題也是發生在鈣矽生醫陶瓷上，就是有硬化時間較長的問題。本團隊在之前的研究之中有發現，以鈣矽生醫陶瓷作為基礎的材料，加入過渡元素之後，可以改善它的機械性制和生物特性，我們將這樣的材料稱為介穩水泥。鋅元素是過渡元素的一種，而他在醫學上的功用，受到大家廣泛的討論。鋅不僅能夠促進細胞生長，也能夠調節骨細胞的分化和形成、硬組織的分化，。鋅也在抗菌方面，也被許多醫療器材當作表面抗菌材料。本團隊已MTA為基礎，也就是鈣矽生醫陶瓷為改良，將鋅元素在材料燒結的過程，摻入到鈣矽生醫陶瓷之中，生產出含鋅的介穩水泥，企圖改善其機械性質，和生物相容性及生物活性，並和市售材料MTA作相互比較。結果發現在機械性質方面，我們可以看到，介穩水泥加入鋅之後可以讓硬化時間大量的縮短，而在抗壓強度和微硬度方面，雖然略低於MTA，但都差距不大，我們推論這可能是和它的水合作用的快慢有關。在水溶液中的酸鹼值和離子釋放濃度方面，可以看到，介穩水泥加鋅之後的酸鹼值，都比MTA還來的接近原來pH值，這樣的情形可以推論，我們的水溶液酸鹼值更適合細胞存活，而這個推論，可以在生物相容性的實驗中獲得到證實。在生物相容性的實驗，介穩水泥加鋅之後的死亡率，比MTA和氫氧化鈣而言都有明顯下降的現象。另外在抗菌的部分的表現，我們發現它在前六個小時的抑菌效果比較明顯，但是時間拉長之後，其效果就開始減低，我們推論會造成這樣的結果，可能是因為E. faecalis對鹼性有比較好的耐受性關係。此外，鋅離子的釋放量，也低於鋅離子的最小殺菌濃度。最後，我們在生物活性方面，觀察結果發現，加鋅之後的介穩水泥，和MTA一樣都有促進鹼性磷酸酶增加的現象，我們可以推論說，含鋅的介穩水泥有刺激細胞分化和礦化的能力。最後，有加鋅的介穩水泥，在鈣離子的釋放量減少，代表著材料的溶解於水中的比例減少，我們可以在近一步大膽假設它的封閉性更好，而這也是我們在未來的實驗中可以再去證實的。總結來說，介穩水泥加入鋅進去之後，以市售材料MTA相互比較，其硬化時間明顯減少，而且抗壓強度和微硬度接近MTA；其酸鹼值和離子釋放變化也減少，更接近人體的體液，所以不會造成細胞傷害，而且也可以含鋅介穩水泥可以促進細胞的分化和礦化。

關鍵字

介穩水泥；生醫陶瓷；含鋅鈣陶瓷；抗菌；生物活性；生物相容性

並列摘要

To keep the tooth health, the technology of dental treatment is continuously processing improved. Among the sticky problems, including apical surgery and retrograde filling, root canal perforation repair, and vital pulp therapy, we are difficult to handle. Fortunately, we could solve this problem by applying the biomaterial improvement. MTA which based on calcium silicate bioceramics is one of the alternatives that be widely applied. As the MTA serves several advantages such as good biocompatibility, bioactive and good sealing ability, it’s most widely applied at the current stage. However, MTA is not an ideal material, for example, it takes long setting time, poor handling property and toxic ions contained, it turns to be critical in clinical application. According to many studies of MTA, many advantages of MTA are based on its main component: calcium silicate, however, our previous study showed that calcium silicate bioceramics had slow hydration rate and long setting time. Our group discovered such transitional elements that added to the calcium silicate cement, it would improve its material properties and we called this new material as Partial-Stabilized Cement (PSC). Zn is an essential trace element, that plays an important role in the body growth and development. Nevertheless, Zn also plays an important role in bone regulation, bone mineralization, stimulation of bone, inhibition of bone resorption, cell replication and differentiation of osteoblast cell. Furthermore, zinc plays an important role in medical material, because it would inhibit microbial growth. The aim of this study is to evaluate the effect of zinc content on material properties, biocompatibility and bioactivity of PSC. About the result, we could discover that the zinc doped to the PSC would reduce the setting time. The compressive strength and microhardness were lower than MTA, but it serves no significant differences. In the pH value, the pH value of PSC+Zn groups were closed to original value, it means this environment was much suitable for cell survival. The conclusion was confirmed form the data that the cell mortal rates of PSC+Zn groups were lower than MTA and Ca(OH)2 group. In the antibacterial test, the all experiment groups were better than control groups during 6 hours, but there were no significant different between all groups after 12 hours. This may be because of some alkalo-tolerant characteristics enabling the reduced susceptibility of E. faecalis. In addition, the zinc ion releasing concentration was lower than the minimum inhibitory concentration. In the bioactivity test, the all PSC+Zn groups were as well as MTA groups. Based upon such test, we could conclude that PSC+Zn groups were stimulate cell differentiation and mineralization. Finally, we can make some conclusions from this study. Firstly, the zinc added to the PSC would improve its material properties. Secondly, The PSC+Zn groups were good at biocompability and bioactivity.

並列關鍵字

Partial-stabilized cement ； bioceramics ； zinc contained calcium silicate ceramic ； antimicrobial ability ； bioactivity ； biocompability

參考文獻

55. 黃瑩潔, 三鈣鋁酸含量對鈣矽陶瓷的材料性質及生物特性之影響. 2011.

82. 李苑玲, 鈣矽生醫陶瓷在牙髓病治療之研發與應用. 臺灣大學臨床牙醫學研究所學位論文, 2006: p. 1-150.

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2. FRIEDMAN, S., The prognosis and expected outcome of apical surgery. Endodontic topics, 2005. 11(1): p. 219-262.

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鋅含量對介穩水泥的材料性質和生物相容性及生物活性之影響

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