Ordered Dental Nanocomposites

描述（由申请人提供）：市售或实验性牙科复合材料的增强材料包括玻璃和二氧化硅颗粒（球形或不规则形状）、玻璃陶瓷或氧化物陶瓷颗粒、陶瓷晶须、电纺聚合物或混合纤维、有机-无机混合颗粒、玻璃纤维、粘土和多面体低聚倍半硅氧烷（POSS）。在掺入复杂的填料共混物后，性能得到了不同程度的改善，但需要进一步增强，以延长牙科修复复合材料的使用寿命和利用率。 目前设计复合材料的范例是，在确定性能时，结构比成分更重要。因此，令人惊讶的是，很少（如果有的话）尝试设计含有有序或周期性排列的增强相的牙科复合材料。我们的创新是利用单分散纳米级胶体二氧化硅颗粒的自组装能力来制造具有有序和紧密填充的填料结构的复合材料。将实施两种生产复合材料的方法：湿胶体晶体工艺和合成蛋白石工艺。 我们提出了三年内要实现的两个具体目标：（1）确定粒径、颗粒表面处理、分散介质和基质树脂对胶体颗粒再分散和有序化效率的影响;和2.）以确定填料颗粒排序对机械性能包括模量、破坏强度和韧性的影响。我们的实验设计要求评估三种粒径，四种硅烷偶联剂，七种基质树脂，四种引发剂水平，和三种填料体积分数。我们将测试这些假设：1。有序的填料排列激活了复合材料中的新变形模式;以及2.）复合材料的强度取决于填料的有序化程度。 拟议的研究将导致新型牙科复合材料的发展，具有改善的美学和较低的聚合收缩（和减少复发性腐烂的发生率）。还有证据表明，有序的填料排列可以带来更高的增强效率和更高的韧性。这些因素将扩大低成本复合材料的适应症。

DESCRIPTION (provided by applicant): Reinforcements of commercially available or experimental dental composites include glass and silica particles (spherical or irregular in shape), glass-ceramic or oxide ceramic particles, ceramic whiskers, electrospun polymer or hybrid fibers, organic-inorganic hybrid particles, glass fibers, clay, and polyhedral oligomeric silsesquioxanes (POSS). Improvements in properties have occurred to varying extents after incorporation of sophisticated filler blends, but further enhancements aimed at extending the service life and utilization of dental restorative composites are desired. The current paradigm for designing composites is that structure matters more than composition when determining properties. It is therefore surprising that there have been few (if any) attempts to design dental composites containing an ordered or periodic arrangement of the reinforcing phase. Our innovation is to utilize the self-assembly capability of monodisperse, nanoscale colloidal silica particles to fabricate composites with an ordered and close-packed filler structure. Two methods of producing composites will be implemented: a wet colloidal crystal process, and a synthetic opal process. We propose two specific aims to be achieved over three years: 1.) to determine the influence of particle size, particle surface treatment, dispersion medium, and matrix resin on the efficiency of colloidal particle redispersion and ordering; and 2.) to determine the effects of filler particle ordering on mechanical properties including modulus, failure strength, and toughness. Our experimental design calls for evaluating three particle sizes, four silane coupling agents, seven matrix resins, four levels of initiator, and three filler volume fractions. We will test these hypotheses: 1.) that an ordered filler arrangement activates new deformation modes in composites; and 2.) that the strength of composites depends on the degree of filler ordering. The proposed research will lead to the development of novel dental composites with improved esthetics and lower polymerization shrinkage (and reduced incidence of recurrent decay). There is also evidence that the ordered filler arrangement leads to greater reinforcing efficiency and higher toughness. These factors will expand the indications for low-cost composite restorations.