Applications of Polymerization-induced Phase Separation of Restorative Materials

描述（由申请人提供）：1999年，美国患者接受了85,788,400个复合修复体，并且这个数字还在继续上升。牙科复合材料修复体代表了最普遍的暴露于生物材料的设计，以恢复替代组织的形式和功能。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。虽然目前的材料一般都很好，但牙科复合材料仍然存在缺陷，限制了它们的效用和性能。这些问题包括：相对较低的转化率导致可浸出单体，这与吸水率一起，随着时间的推移，机械性能下降；缺乏韧性；最重要的是，过度的聚合收缩会造成压力。与聚合相关的收缩和应力意味着不能可靠地获得完整的修复边缘。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，这些多功能性允许控制异质结构的形成。聚合诱导相分离将用于制造纳米到微尺度的非均相聚合物材料，这些材料具有高转化率，提高韧性，特别是由于这种方法特有的后期收缩恢复，应力发展最小。该研究计划提供开发(i)形成非均相聚合物的全甲基丙烯酸酯树脂组合物；（ii）通过自由基和阳离子光聚合过程同时应用于具有不同反应官能团的单体混合物中，可以控制非均相互穿聚合物网络的形成；（iii）为增强填料引入新的表面处理，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。该计划将清楚地描述有效的控制参数，这些参数可用于操纵聚合诱导相分离过程，以生产低收缩率和低应力的聚合物材料，并且相对于传统的均质材料具有更高的强度、耐久性和韧性。由此产生的复合配方将适合作为下一代，改进的牙科修复体。这项研究将促进对复杂聚合物系统的基本理解，同时提供修复材料的短期和中期临床效益。

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.