活動義齒基底材料常見的問題有二 (1)材料與軟內襯之間黏著力不足；(2) 口腔微生物在材料表面的生長。本研究利用聚甲基丙烯酸甲酯 (polymethyl methacrylate, PMMA) 熱固式假牙基底層 (Luctione 199) 以及矽橡膠 (silicone rubber) 基底的熱聚式軟內襯 (Molloplast B) 為實驗材料。
本研究利用兩種接枝方法：酯化反應 (esterification reaction)以及點擊化學反應 (click chemistry reaction) 接枝聚乙二醇甲醚 (mPEG) 於假牙基底層材料 (PMMA)，以改變表面性質。其中兩種接枝方法，皆需改質聚乙二醇甲醚高分子末端官能基，而假牙基底材料也需修飾具有對應之官能基，以便進行接枝。聚乙二醇甲醚與聚乙二醇分子結構相似，但是僅有一端具有羥基官能基，因此能有效進行專一性的接枝，本研究將聚乙二醇甲醚接枝於假牙基底材料表面上，則是利用聚乙二醇甲醚在液相中型態會由捲曲密集伸展開形成梳狀狀結構，並且其水濕性會隨時間的增加而提高之性質，降低蛋白質或細胞之貼附。聚乙二醇甲醚的末端基改質前後用傅立葉轉換紅外光譜儀 (FTIR) 觀察官能基之變化，用液態核磁共振儀 (1H NMR) 鑑定聚乙二醇甲醚末端基改質是否成功。高分子接枝於假牙基底層表面後，利用電子能譜化學分析儀 (ESCA) 分析材料表面的化學鍵結，以及以掃瞄式電子顯微鏡 (SEM) 觀察表面型態之變化。
本研究所利用的兩種接枝的方法進行假牙基底層之改質皆能提高抗沾黏效率，首先，是利用酯化反應將兩種分子量2000 g/mole及5000 g/mole的聚乙二醇甲醚接枝於假牙基底層上，抗沾黏效率分別達到39.8 %及36.5 %。其次，利用點擊化學方法將兩種分子量的聚乙二醇甲醚接枝於假牙基底層上，發現可達到較高之抗沾黏效率，分別為63.4 %及81.3 %。
拉伸強度測試的結果，顯示利用不同的接枝方法接枝不同分子量的聚乙二醇甲醚，對於假牙基底層拉伸強度均有影響，其中利用酯化反應的方法接枝分子量2000 g/mole的聚乙二醇甲醚會與未改質之假牙基底層結果皆於軟內襯造成斷裂，因其表面與軟內襯具有較強的黏著力，而實驗可知軟內襯可承受1.2 MPa的拉伸強度，並可推得黏著力與未改質的假牙基底層相近。而接枝分子量5000 g/mole表面與軟內襯黏著力較低約為0.70 MPa，其拉伸結果於黏著面造成分離。利用點擊化學方法，接枝分子量2000 g/mole與5000 g/mole聚乙二醇甲醚，其表面與軟內襯黏著力皆較低，分別為0.6 MPa及0.3 MPa，其拉伸結果會於黏著面造成分離。

The common problems encountered for dentures include: (i) the loss of adhesion between soft linings and denture base, and (ii) the growth of microorganism and formation of biofilm on the denture which usually resulted in bad smelling and hygiene concerns. This study aims to incorporate antifouling molecules onto the denture base materials and to evaluate the variation of the adhesion between soft linings (Molloplast B) and denture bases (Luctione 199).
Two chemical grafting methods were proposed in this study to incorporate mPEG (poly(ethylene glycol) methyl ether), a derivative of PEG (polyethylene glycol), on the denture base which is mainly composed of PMMA (polymethyl methacrylate). The first method involved to modify one end of mPEG from –OH group to –COOH by reacting with succinic anhydride (forming mPEG-COOH), and further reacted with thionyl chloride to form mPEG-COCl. PMMA denture base was reacted with LiAlH4 to form PMMA-OH that the highly reactive mPEG-COCl would react with PMMA-OH to specifically graft mPEG on PMMA and form mPEG-PMMA. In this part of studies, different solvents systems and two molecular weight of mPEG were used to study their effects on fouling resistance. The formed products were named as mPEG-2k-COCl-PMMA and mPEG-5k-COCl-PMMA.
The second chemical graft method is to modify mPEG and PMMA both in two steps. PMMA was firstly reacted with LiAlH4 and propargyl bromide to form PMMA-OH and PMMA- alkyne, respectively. The –OH end group of mPEG was modified by thionyl chloride and sodium azide (NaN3) to form mPEG-Cl and mPEG-N3, sequentially. The alkyne-azide reaction between PMMA- alkyne and mPEG-N3 was specific and commonly called “click chemistry” reaction. Two different M.W. of mPEG were studied and the formed products were named as mPEG-2k-click-PMMA and mPEG-5k-click-PMMA.
The mPEG incorporation is believed to provide the brush-like structure on the surface of PMMA to resist the adhesion of biomolecules. Moreover, the identification of chemical structure and synthesis were performed using FTIR, 1H NMR and ESCA. The surface morphology was visualized by SEM. The results showed that the two proposed methods increased the antifouling efficiency on the dental based materials. Firstly, the “esterification” reaction resulted in 39.8 % and 36.5 % for mPEG-2k-COCl-PMMA and mPEG-5k-COCl-PMMA. Furthermore, the “click chemistry” reaction promoted the antifouling efficiency up to 63.4 % and 81.3 % on mPEG-2k-click-PMMA and mPEG-5k-click-PMMA. The results of mechanical tests showed that the similar mechanical strength was obtained between soft lining and denture base on mPEG-2k-COCl-PMMA.The other three modifications resulted in slightly decreases of mechanical strength between the modified denture base and soft linings.

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