Application of Nanogel-modified Resins for Improved Polymeric Dental Materials

描述(由申请人提供)：在美国每年进行的超过1亿次的牙科修复治疗中，大部分涉及树脂粘结复合材料的放置，而且人们认识到，牙医花费了大量时间来修改和更换这些修复体，因此显然需要改善临床性能的材料。与牙科汞合金相比，复合修复剂不仅具有美学优势，而且提供了一种将修复体粘结到牙本质和牙釉质上的方法。然而，由于聚合收缩应力从放置时就挑战了这一关键界面，目前不能可靠地获得坚固、完整的边际。最近发展了一种高度通用的技术来制备纳米级(5-100 nm)聚合物粒子，并控制支化、化学和反应位置。这些反应性纳米凝胶可以在高浓度下很容易地分散在二次单体中，然后渗透到预聚体添加剂中，然后与预聚体添加剂共聚。这种方法大大减少了聚合收缩和应力，并证明了提高牙科树脂和复合材料模型强度的能力。拟议的项目将把积极的初步成果扩展到用于修复应用的高填充、低应力、纳米凝胶改性复合材料的实际应用中，同时还将开发依赖于互穿聚合物网络的新型密封材料，以在贴装过程中大幅降低游离单体水平。基于纳米凝胶的生物活性密封剂也将被开发和展示，这种密封剂具有抗细菌和潜在的基质金属蛋白酶抑制特性。该应用围绕三个目标构建：i)纳米凝胶合成的基础研究，旨在生产具有可预测性能的良好控制的纳米凝胶结构，主要关注具有实际有用的粘度的单体基质中的高纳米凝胶含量与光学性能之间的平衡；ii)纳米凝胶在 对于牙科复合材料，将寻求相对于纳米凝胶含量更大比例的应力降低，同时还将提高潜在块状填充复合材料的断裂韧性，这种复合材料结合了纳米凝胶和新型表面处理的无机填料的高负载水平；以及iii)使用纳米凝胶创建具有互穿聚合物网络的密封材料，形成的转化率高，对氧气抑制的敏感性降低，这意味着更稳定的材料，更少的可浸出化合物释放。密封材料平台将进一步扩展，以展示具有化学集成纳米凝胶的聚合物的潜在生物活性，这些纳米凝胶具有杀菌和抑制基质金属蛋白酶的特性。

DESCRIPTION (provided by applicant): With a majority of the more than 100,000 million dental restorative treatments performed in the US each year involving the placement of resin-bonded composite materials, and the acknowledgement that a large portion of a dentist's time is consumed with revising and replacing these restorations, there is a clear need for materials with improved clinical performance. Composite restoratives not only hold an esthetic advantage over dental amalgams, but they offer a means to adhesively bond the restoration to dentin and enamel. However, due to polymerization shrinkage stresses that challenge this critical interface from the time of placement, a strong, intact margin can not currently be reliably obtained. A highly versatile technique has been developed recently for preparing nano-scale (5 - 100 nm) polymeric particles with control over branching, chemistry and reactive site placement. These reactive nanogels can be dispersed readily at high concentrations in secondary monomers, which then infiltrate and subsequently copolymerize with the prepolymer additives. This approach has provided substantial reductions in polymerization shrinkage and stress, as well as a demonstrated ability to improve the strength of a model dental resin and composite. The proposed project would extend the positive preliminary results into practical examples of highly filled, low stress, nanogel-modified composites for restorative applications while also developing new sealant materials that rely on interpenetrating polymer networks to achieve dramatically reduced levels of free monomer during placement. Bioactive sealants based on nanogels that display anti-bacterial and potentially MMP-inhibiting properties will also be developed and demonstrated. The application is constructed around three aims: i) fundamental studies of nanogel synthesis designed to produce well controlled nanogel structures with predictable properties with a primary focus on a balance between high nanogel contents in monomeric matrices with practically useful viscosities and optical properties; ii) application of nanogels in dental composites where greater than proportional reductions in stress, relative to the nanogel content, will be sought while also improving the fracture toughness of potentially bulk filling composites that combine high loading levels of both nanogel and novel surface-treated inorganic fillers; and iii) use of nanogels to create sealant materials with interpenetrating polymer networks that form with high conversion and a reduced sensitivity to oxygen inhibition, which means more stable materials with much less leachable compound release. The sealant material platform will be further extended to demonstrate the potential bioactivity of polymers with chemically integrated nanogels that convey bactericidal and MMP- inhibition properties.