Dental resin adhesive is a mixture of monomers used as an adhesive in resin-based composite tooth restoration. Methacrylate monomers used in these adhesives are susceptible to hydrolysis by bacterial enzymes, leading to limitation of their lifespan. To overcome this issue, in this research series of quaternary ammonium-containing methacrylamides, MDAB (methacrylamidoethyl dimethyl ammonium bromide) and MDAF (methacrylamidoethyl dimethyl ammonium fluoride), acrylamides, ADAB (acrylamidoethyl dimethyl ammonium bromide) and bismethacrylamides, bis-MMAI (bis(2-methacrylamidoethyl)methyl ammonium iodide) were synthesized. These new monomers exhibited antibacterial properties against common bacteria found in tooth cavities, which are S. mutans and E. faecalis. Extra methyl moiety on polymerizable group and long alkyl chain length increased antibacterial properties as well as cytotoxicity against MDPC.23 mouse dental papilla cell lines. Acrylamides, ADAB showed the least cytotoxicity with higher MBC values than the commonly used methacrylate monomer, bis-GMA and the only antibacterial methacrylate-based monomer currently used in commercial resin adhesives, MDPB (methacryloyldodecylpyridinium bromide). Steric hindrance and lipophilicity of bismethacrylamides in bis-MMAI series reduced antibacterial activities and also significantly enhanced cytotoxicity of the monomers. Moreover, bromide and fluoride counter ions in MDAB and MDAF, respectively, did not cause any difference in antibacterial effects. Additionally, all synthesized (meth)acrylamide monomers demonstrated greater stability against hydrolysis under acidic conditions compared to the methacrylate MDPB. Degree of conversions of synthesized monomers were lower than that of MDPB at the beginning of polymerization due to the higher viscosity, but were comparable at the latter stage. Methyl group on methacrylamides in MDAB and the highest viscosity of bismethacrylamides, bis-MMAI reduced degree of conversions of the monomers. TADAB (tetradecylacrylamidoethyl dimethyl ammonium bromide) incorporated in resin adhesive reduced water solubility of the cured resin under acidic condition.

中文翻译：

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用于牙科树脂胶粘剂的（甲基）丙烯酰胺基单体的合成、抗菌活性和耐水解性


牙科树脂胶粘剂是单体的混合物，用作树脂基复合牙齿修复中的胶粘剂。这些胶粘剂中使用的甲基丙烯酸酯单体容易被细菌酶水解，导致其使用寿命受到限制。为了克服这个问题，在这个含季铵盐甲基丙烯酰胺的研究系列中，合成了 MDAB（甲基丙烯酰胺乙基二甲基溴化铵）和 MDAF（甲基丙烯酰胺乙基二甲基氟化铵）、丙烯酰胺、ADAB（丙烯酰胺乙基二甲基溴化铵）和双甲基丙烯酰胺，合成了双 MMAI（双（2-甲基丙烯酰胺乙基）甲基碘化铵）。这些新单体对牙腔中发现的常见细菌（即变形链球菌和粪肠球菌）表现出抗菌特性。可聚合基团上的额外甲基部分和长烷基链长度增加了抗菌性能以及对 MDPC.23 小鼠牙科细胞系的细胞毒性。丙烯酰胺 ADAB 的细胞毒性最小，MBC 值高于常用的甲基丙烯酸酯单体 bis-GMA，并且是目前商业树脂胶粘剂中唯一使用的抗菌甲基丙烯酸酯基单体 MDPB（甲基丙烯酰十二烷基吡啶溴化物）。bis-MMAI 系列中双甲基丙烯酰胺的空间位阻和亲脂性降低了抗菌活性，也显着增强了单体的细胞毒性。此外，MDAB 和 MDAF 中的溴化物和氟化物反离子分别在抗菌效果上没有引起任何差异。此外，与甲基丙烯酸酯 MDPB 相比，所有合成的（甲基）丙烯酰胺单体在酸性条件下都表现出更高的抗水解稳定性。 由于粘度较高，合成单体在聚合开始时的转化率低于 MDPB，但在后期相当。MDAB 中甲基丙烯酰胺上的甲基和双甲基丙烯酰胺的最高粘度，bis-MMAI 降低了单体的转化率。TADAB（四十烷基酰胺乙基二甲基溴化铵）掺入树脂胶粘剂中，降低了固化树脂在酸性条件下的水溶性。