Applications of Polymerization-induced Phase Separation of Restorative Materials

描述(申请人提供)：1999年，美国的患者接受了85,788,400个复合修复体，而且这个数字还在继续上升。牙科复合修复体是最常见的生物材料修复材料，用于修复被替换组织的形态和功能。因此，这些广泛使用的材料的进一步改进将对医疗保健产生相当大的影响。虽然目前的材料总体上是好的，但牙科复合材料仍然存在不足，限制了它们的实用性和性能。这些问题包括：转化率相对较低，导致可浸出单体，随着时间的推移，随着吸水率的增加，机械性能会下降；缺乏韧性；最重要的是，聚合收缩过大，导致应力。与聚合相关的收缩和应力意味着，不能可靠地实现完整的恢复利润率。所有这些问题都使修复体的放置复杂化，并限制了它们的使用寿命。在这个项目中，我们通过聚合物材料固有的多功能性来解决这些问题，这种材料允许控制异质结构的形成。聚合诱导相分离将被用来创造纳米到微米尺度的多相聚合物材料，具有高转化率，改善的韧性，特别是，由于这种方法独特的后期收缩恢复，具有最小的应力发展。该研究计划将用于开发(I)形成非均相聚合物的全甲基丙烯酸酯树脂组合物，(Ii)通过同时应用于具有不同活性官能团的单体混合物的自由基光聚合和阳离子光聚合过程来控制异质互穿聚合物网络的形成，以及(Iii)引入用于增强填料的新型表面处理，该表面处理在基于相分离树脂的复合材料中提供补充的额外定制界面。该程序将清楚地描述有效的控制参数，这些参数可用于控制聚合诱导相分离过程，以生产与传统均质材料相比具有更高强度、耐久性和韧性的低收缩和低应力聚合物材料。这些合成的复合配方将适合作为下一代改进的牙科修复剂。这项研究将促进对复杂聚合物系统的基本了解，同时提供修复材料的短期和中期临床益处。

DESCRIPTION (provided by applicant): In 1999, patients in the USA received 85,788,400 composite restorations and the numbers continue to rise. Dental composite restorations represent the most prevalent exposure to biomaterials designed to restore form and function of replaced tissues. As such, further improvements in these widely used materials will have a considerable health care impact. While current materials are generally good, dental composites still suffer from deficiencies that limit their utility and performance. These problems include: relatively low conversion leading to leachable monomer, which along with water uptake, provide a decline in mechanical properties over time; lack of toughness; and most significantly, excessive polymerization shrinkage that causes stress. Shrinkage and stress associated with polymerization mean that intact restored margins can not be achieved reliably. All these problems complicate the placement of restorations and limit their service life. In this project, we address these issues through the inherent versatility of polymeric materials that allows controlled formation of heterogeneous structures. Polymerization-induced phase separation will be used to create nano- to micro-scale heterogeneous polymeric materials with high conversion, improved toughness and notably, with minimal stress development due to a late-stage shrinkage recovery unique to this approach. The research plan provides for development of (i) all-methacrylate resin compositions that form heterogeneous polymers, (ii) controlled formation of heterogeneous interpenetrating polymer networks obtained by simultaneous free radical and cationic photopolymerization processes applied to mixtures of monomers with different reactive functional groups and (iii) introduction of novel surface treatments for reinforcing fillers that provide a complementary additional tailored interface in composite materials based on the phase-separating resins. The proposed program will clearly delineate the effective control parameters that can be used to manipulate the polymerization-induced phase separation process to produce low shrinkage and low stress polymeric materials with improved strength, durability and toughness relative to conventional homogeneous materials. These resulting composite formulations will be suitable as next generation, improved dental restoratives. This research will advance fundamental understanding of complex polymeric systems while providing short- and medium-term clinical benefits with restorative materials.