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Abstract：
Hydrolytically and enzymatically-stable multi-acrylamides have been proposed to increase the long-term durability of dental adhesive interfaces as alternatives to methacrylates. The aim of this study was to investigate the mechanical and biochemical properties of experimental adhesives containing multi-functional acrylamides concerning collagen reinforcement and metalloproteinases (MMP) activity. Multi-functional acrylamides, TMAAEA (Tris[(2-methylaminoacryl) ethylamine) and DEBAAP (N,N-Diethyl-1,3-bis(acrylamido) propane), along with the commercially available DMAM (N,N-dimethylacrylamide) (monofunctional acrylamide) and HEMA (2-Hydroxyethyl methacrylate) (monofunctional methacrylate - control) were tested for stability against enzymatic hydrolysis by cholesterol esterase/pseudocholinesterase (PC/PCE) solutions for up to 30 days. Collagen-derived substrate and gelatin zymography were performed to examine the effect of the compounds on the biological activity of human recombinant and dentin-extracted gelatinases MMP-2 and MMP-9. In situ zymography was carried out by fluorescent collagen degradation combined with confocal microscopy analysis. Hydroxyproline content was measured in collagen derived from dentin extracts though reaction with Ehrlich\'s reagent p-dimethylaminobenzaldehyde (DMAB), generating a stable chromophore measured at 550 nm. Storage shear modulus of demineralized dentin discs treated with the tested compounds was measured by oscillatory rheometry, in order to investigate potential collagen reinforcement. FT-IR was performed to determine qualitative differences in collagen based on observed changes in amide bands. The results were analyzed by ANOVA/Tukey\'s test (α = 0.05). Multi-acrylamides survived 30 days of incubation in cholinesterase/pseudo-cholinesterase (PC/PCE) solutions, while HEMA showed approximately 70 % overall degradation. Incubation with multi-acrylamides reduced collagen degradation as evidenced by the reduced hydroxyproline levels and by the 30 % increase inshear storage modulus. Biochemical and zymography assays showed no noticeable inhibition of recombinant and extracted MMPs enzymatic activity. The infra-red spectroscopy results for multi-functional acrylamides treated samples demonstrated shifts of the amide II bonds and marked increase in intensity of the bands 1200 cm-1, which may indicate partial collagen denaturation and some degree of cross-linking of the compounds with collagen, respectively. The multi-acrylamides exhibited not only comparable mechanical properties but also demonstrated significantly enhanced biochemical stability when compared to the widely used methacrylate control. Clinical relevance: These findings highlight the potential of multi-acrylamides to increase the bonding stability to tissues and, ultimately, contribute to the longevity of dental restorations.
摘要：
已经提出了水解和酶稳定的多丙烯酰胺作为甲基丙烯酸酯的替代品来增加牙科粘合剂界面的长期耐久性。这项研究的目的是研究含有多功能丙烯酰胺的实验粘合剂的机械和生化特性，这些粘合剂涉及胶原蛋白增强和金属蛋白酶（MMP）活性。多功能丙烯酰胺，TMAAEA（三[（2-甲基氨基丙烯酰基）乙胺）和DEBAAP（N，N-二乙基-1,3-双(丙烯酰胺基)丙烷)，连同市售的DMAM(N，测试N-二甲基丙烯酰胺）（单官能丙烯酰胺）和HEMA（甲基丙烯酸2-羟乙酯）（单官能甲基丙烯酸酯-对照）对胆固醇酯酶/假胆碱酯酶（PC/PCE）溶液酶促水解的稳定性长达30天。进行胶原衍生的底物和明胶酶谱以检查化合物对人重组和牙本质提取的明胶酶MMP-2和MMP-9的生物活性的影响。通过荧光胶原降解结合共聚焦显微镜分析进行原位酶谱。通过与Ehrlich试剂对-二甲基氨基苯甲醛(DMAB)反应,从牙本质提取物中提取的胶原中测定羟脯氨酸含量,产生在550nm处测量的稳定发色团。通过振荡流变仪测量用测试化合物处理的脱矿质牙本质盘的存储剪切模量，为了研究潜在的胶原蛋白增强。进行FT-IR以基于观察到的酰胺条带变化来确定胶原的定性差异。结果采用方差分析/Tukey检验(α=0.05)。多丙烯酰胺在胆碱酯酶/假胆碱酯酶（PC/PCE）溶液中孵育30天，而HEMA显示约70%的总体降解。与多种丙烯酰胺一起孵育可减少胶原蛋白的降解，如羟脯氨酸水平降低和剪切储能模量增加30％所证明的。生化和酶谱测定显示重组和提取的MMPs酶活性没有明显抑制。用多功能丙烯酰胺处理的样品的红外光谱结果表明，酰胺II键的移动和1200cm-1条带强度的显着增加，这可能表明部分胶原蛋白变性和化合物的一定程度的交联与胶原蛋白，分别。与广泛使用的甲基丙烯酸酯对照相比,多丙烯酰胺不仅表现出相当的机械性能,而且还表现出显著增强的生化稳定性。临床相关性：这些发现强调了多丙烯酰胺增加与组织的结合稳定性的潜力，最终,有助于牙科修复的寿命。
