Im/Miscible Adhesive/Dentin Interface:Structure/Mechanic

说明：如果复合树脂被认为是牙科汞合金的可行替代品，则必须改善牙本质/粘合剂（d/a）粘合的耐久性。在体内条件下，这种结合可以成为抵抗物质渗透并最终破坏复合修复的第一道防线。d/a债券的存续期直接关系到现金流的质量，但衡量质量一直是一个棘手的问题。到目前为止，我们的大多数技术都提供了间接评估，例如，测量体积d/a试样在水浸泡前后的抗破裂性的测试方法不够敏感，无法识别水降解开始的界面缺陷。我们最近对杂化层分子结构和微观力学的原位表征表明，BisGMA/HEMA粘合剂在脱矿牙本质中与水混合时会发生物理分离，这是一个严重的限制。临界二甲基丙烯酸酯（BisGMA）是对交联聚合物粘合剂贡献最大的成分，它渗入了一小部分湿的、脱矿的牙本质。这项工作的总体假设是，在临床相关的潮湿牙本质表面存在的情况下，与最先进的商业粘合剂相比，甲基丙烯酸酯基粘合剂配方中含有水相容成分，可以减少相分离，从而增强结构完整性，提高混合层的耐久性。具体目标将测试假设：1)阳离子表面活性剂、水相容光引发剂和水相容交联二甲基丙烯酸酯共聚物在甲基丙烯酸酯基粘合剂配方中将减少发生在水中的相分离，并协同作用以减少与这种相分离相关的有害影响；2)这些由水相容成分配制的胶粘剂将增强牙本质的渗透，并在适当的粘度下与健康牙本质和受龋齿影响的牙本质的湿脱矿基质混溶；3)健康牙本质与患龋牙本质的界面弹性模量与甲基丙烯酸酯基胶粘剂的相分离和水相容性降低，在水环境下界面弹性模量是稳定的，并且在加载过程中界面弹性模量不会导致应力集中而导致界面破坏；4)与最先进的商业粘合剂相比，甲基丙烯酸酯基粘合剂在湿脱矿健康牙本质基质存在下表现出相分离减少、渗透增强、混溶性改善和结构完整性，将提供强大、持久的d/a键。

DESCRIPTION: If composite resins are to be considered a viable alternative to Dental amalgam, the durability of the dentin/adhesive (d/a) bond must be improved. Under in vivo conditions, this bond can be the first defense against substances that penetrate and ultimately undermine the composite restoration. The durability of the d/a bond is directly related to the quality of the HL but measuring quality has been a formidable problem. To date, the majority of our techniques have provided an indirect assessment, e.g., testing methods that measure fracture resistance of bulk d/a specimens pre- and post-water immersion are not sensitive enough to identify interfacial defects where aqueous degradation begins. Our recent in situ characterization of the molecular structure and micro-mechanics of the hybrid layer has indicated a serious limitation-physical separation of the BisGMA/HEMA adhesive upon mixing with water in the demineralized dentin. The critical dimethacrylate (BisGMA), the component contributing most to the cross-linked polymeric adhesive, infiltrated a fraction of the wet, demineralized dentin. The overall hypothesis of this work is that in the presence of moist clinically relevant dentin surfaces, methacrylate-based adhesives formulated to include water-compatible components will provide decreased phase separation and thus, enhanced structural integrity and increased durability of the hybrid layer as compared to state-of-the-art commercial adhesives. The Specific Aims will test the hypotheses: 1) cationic surfactants, water compatible photoinitiators and water-compatible cross-linking dimethacrylate co-monomers in methacrylate-based adhesive formulations will decrease phase separation that occurs in water and act synergistically to reduce the detrimental effects associated with such phase separation; 2) these adhesives formulated with water-compatible components will provide enhanced dentin infiltration and be miscible with wet demineralized matrices of healthy and caries-affected dentin, assuming suitable viscosity; 3) the module of elasticity at the interface of healthy dentin and caries-affected dentin with methacrylate-based adhesives exhibiting reduced phase separation and water compatible characteristics will be stable upon exposure to aqueous environments and that the interfacial elastic moduli will not lead to stress concentration that will result in failure initiation at the interface during loading; 4) that methacrylate-based adhesives exhibiting reduced phase separation, enhanced infiltration, improved miscibility and structural integrity in the presence of wet demineralized healthy dentin matrices will provide strong, durable d/a bonds as compared to state-of-the-art commercial adhesives.