中文摘要：

目的研究自行合成的一种季铵盐型抗菌甲基丙烯酰氧乙基－正十四烷基－二甲基氯化铵（DMAE—TB）对口腔常见致病菌的抗菌活性、抗菌动力学及细胞毒性。方法采用液体稀释法研究季铵盐单体对8种口腔常见致病菌的抗菌活性和杀菌动力学。并采用MTT法初步考察此单体的细胞毒性作用。结果季铵盐单体DMAE－TB对8种口腔致病菌均表现出较高的抗菌活性，最小抑菌浓度（MIC）值介于2．4～9．8μg/ml之间。该单体在浓度为79．2μg/ml时与变形链球菌接触1min，能杀灭99％的细菌；接触5min，即可杀灭所有细菌。细胞毒性实验表明DMAE—TB对细胞增殖的半数抑制浓度为8．21μg／ml。结论DMAE—TB对口腔常见致病菌具有强效、快速的抗菌活性，生物安全性较理想，具有应用于牙科抗菌修复材料的前景。

英文摘要：

Objective To study the antibacterial activity, time-kill kinetics and cytotoxicity of a newly synthesized quaternary ammonium antibacterial monomer - methacryloxylethyl tetradeeyl ammonium chloride （DMAE-TB）. Methods The antibacterial activity and time-kill kinetics of the monomer against eight oral pathogenic bacteria were studied using the broth dilution test, and the cytotoxicity was evaluated by MTT assay. Results DMAE-TB showed strong antibacterial activity against all the eight pathogenic bacteria, with the values of minimum inhibitory concentration （MIC） ranging from 2.4 to 9.8 μg/ml. At the concentration of 79. 2 μg/ml, DMAE- TB revealed rapid bactericidal activity against Streptococcus Mutans （S. mutans） by killing 99% of the bacteria within 1 minute and almost all the bacteria within 5 minutes＇contact. Cytotoxocity test suggested that the 50% inhibiting concentration （IC50） of the monomer DMAE-CB was 8.21 μg/ml. Conclusion The new quaternary ammonium antibacterial monomer DMAE-CB with strong and rapid bactericidal activity and acceptable biocompatibility may provide a promising strategy to harvest effective antibacterial dental materials.