Ordered Dental Nanocomposites

说明(申请人提供)：商用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)、微晶玻璃或氧化物陶瓷颗粒、陶瓷晶须、电纺聚合物或混杂纤维、有机-无机混杂颗粒、玻璃纤维、粘土和多面体低聚倍半硅氧烷(POSS)。在加入复杂的填料混合物后，性能发生了不同程度的改善，但旨在延长牙科修复复合材料的使用寿命和使用的进一步增强是需要的。 目前设计复合材料的范例是，在决定性能时，结构比组成更重要。因此，令人惊讶的是，很少有人(如果有的话)尝试设计包含增强相有序或周期性排列的牙科复合材料。我们的创新是利用单分散纳米胶体二氧化硅颗粒的自组装能力来制备具有有序和紧密堆积的填料结构的复合材料。将实施两种制备复合材料的方法：湿法胶体结晶法和合成蛋白石法。 我们建议在三年内实现两个具体目标：1.确定颗粒大小、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；确定填料颗粒有序性对力学性能的影响，包括模数、破坏强度和韧性。我们的实验设计要求评估三种颗粒大小、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。我们将检验这些假设：1.)有序的填料排列在复合材料中激活了新的变形模式；复合材料的强度取决于填料的有序度。 拟议的研究将导致新型牙科复合材料的开发，具有更好的美观性和更低的聚合收缩(以及减少复发龋齿的发生率)。也有证据表明，有序的填料排列导致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修复体的适应症。

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.