RESTORATIVE MATERIAL WEAR FACTORS

说明(申请人提供)：牙科复合材料在前部地区仍然是最受欢迎的修复材料，尽管它们的使用仅限于单个单位的修复。在前部和后部修复体中，寿命都受到两个因素的限制：聚合收缩和机械故障。尽管复合材料的性能在不断提高，但它们的韧性、耐久性和强度仍然不足，特别是当考虑到大型修复时。在接近和咬合接触区域，磨损仍然是一个令人担忧的问题。 与树脂基组分相关的研究目前集中在收缩问题上；与填料组分相关的研究目前主要集中在替代的填料形态、颗粒尺寸和填料组成上。在牙科领域，除了探索硅烷化变量外，关于填料-基质界面的研究相对较少，尽管结构复合材料社区最近普遍关注工程界面的概念，以此作为改善复合材料性能的一种手段。然而，这个群体主要对纤维增强的复合材料感兴趣，而不是颗粒增强的复合材料。我们建议将这一概念用于设计更坚固和特别坚韧的牙科复合材料，以扩大复合修复体的适应症。 在设计新材料时，采用一种缩短开发时间和具有预测能力的方法是有用的。我们已经成功地实现了用于预测颗粒填充复合材料的弹性系数和韧性的有限元(FE)建模，并建议将该方法扩展到更复杂的复合材料系统，并结合验证有限元模型的实验方法。具体来说，我们提出了以下目标：1)制造、模拟和预测含有延展性有机添加剂的基质聚合物的增韧；我们的假设是，这种化合物(伸长率=400%)的存在促进了可塑性和能量耗散。制造、模拟和预测具有新型韧性界面相的复合材料的增韧；我们的假设是，界面相的存在提供了额外的塑性，并通过裂纹钉扎机制增强了韧性；模拟填料颗粒大小和形状对复合材料强度和韧性的影响。 这项工作的结果将是更长寿命复合材料的合理设计的蓝图。

DESCRIPTION (provided by applicant): Dental composites continue to be favored restorative materials in the anterior region, although their use is limited to single-unit restorations. In both anterior and posterior restorations, lifetimes are limited by two factors: polymerization shrinkage and mechanical failure. Although composite properties continue to improve, their toughness, durability, and strength remain inadequate, particularly when large restorations are considered. Wear is still a concern in approximal and occlusal contact areas. Studies related to the resin matrix component currently focus on the shrinkage problem; studies related to the filler component currently focus on alternative filler morphologies, panicle sizes, and filler composition. Relatively little in the dental community has been done concerning the filler-matrix interface beyond exploring silanation variables, although the structural composites community at large has recently focused on the concept of an engineered interphase as a means of improving composite properties. However, that community is primarily interested in fiber-reinforced, not particulate-reinforced composites. We propose to adapt this concept for the design of stronger and especially tougher dental composites in order to expand the indications for composite restorations. In designing new materials, it is useful to adopt a methodology that shortens development time and has predictive power. We have experienced success in implementing finite element (FE) modeling for predicting the modulus and toughness of particulate filled composites, and propose extending this approach to more complex composite systems in combination with an experimental approach that validates the FE models. Specifically, we propose the following aims: 1.) To fabricate, model, and predict toughening of matrix polymers containing ductile organic additives; our hypothesis is that the presence of such compounds (% elongation=400%) promotes plasticity and energy dissipation.; 2.) To fabricate, model, and predict toughening of composites with novel ductile interphases; our hypothesis is that the presence of the interphase provides additional plasticity and augments toughening by the crack-pinning mechanism; and 3.) To model the effect of filler particle size and shape on composite strength and toughness. The outcome of this work will be a blueprint for the rational design of longer-lived composites.