Cu-Catalyzed Azide-Alkyne Reactions for Novel Dental Composite Materials

描述（由申请人提供）：每年进行的超过一亿次牙科修复中，超过60%涉及使用光聚合聚合物复合材料。尽管它们在现代牙科中无处不在，但这些复合材料存在限制其适用性和实用性的重大问题。基于近50年前开发和实施的树脂化学，这些材料的问题包括与固化后可提取的未反应单体的存在、单体和复合材料的降解、聚合收缩和收缩引起的应力、聚合的长时间框架、缺乏韧性和树脂材料的其他机械行为相关的问题，聚合后样品的热和水分吸收。由于平均使用寿命不到8年，这些问题的结果通常是复合材料的过早失效，这是由于继发性龋齿或本体内或界面处的机械失效造成的。我们建议开发和评估一种复合修复系统的基础上，现在经典的“点击”反应，即铜催化叠氮化物-炔（CuAAC）反应。其特征包括实现高转化率而无副反应，在环境下稳定且易于进行，并且形成不易被酸、水或酶降解的产物。此外，反应的产物是能够进行二级分子相互作用的三唑环结构（即，非共价键形成），其增强交联聚合物材料的韧性、玻璃化转变和模量。因此，本研究将通过以下方式解决甲基丙烯酸酯复合材料体系的关键缺点：（i）开发一种全新的方法来处理这些复合材料的树脂部分，该方法以一种将导致实现接近定量的官能团转化、限制可提取单体、消除水解和酶促降解的可能性、通过次级分子相互作用改善机械性能的方式实现CuAAC反应，并显著降低收缩和应力;（ii）将这种新型的CuAAC基树脂相与适当官能化的填料组合以实现所需的机械性能、改善断裂韧性、延长这些聚合物的寿命并实现复合材料的增强的尺寸稳定性;和（iii）分析这些树脂和复合材料的粘附、降解、提取和其它长期性能指标。光诱导CuAAC聚合体系非常适合下一代牙科清洁剂，我们的目标是开发一种复合体系，该体系与当前的牙科实践和粘合剂相容，但这些清洁剂的使用寿命至少增加两倍。

DESCRIPTION (provided by applicant): More than 60% of the more than one hundred million dental restorations performed each year involve the use of photopolymerizable polymeric composites. Despite their ubiquitous presence in modern dentistry, these composites suffer from significant problems that limit their applicability and utility. Based on resin chemistry developed and implemented nearly 50 years ago, the problems with these materials include issues associated with the presence of extractable, unreacted monomer following cure, degradation of the monomers and composite, polymerization shrinkage and shrinkage induced stresses, the long timeframe for polymerization, lack of toughness and other mechanical behavior of the resin material, thermal and moisture uptake by the sample following polymerization. With less than an 8 year average service life, the result of these problems is often the premature failure of composite restorations, resulting either from secondary caries or from mechanical failure within the bulk or at the interface. We propose to develop and evaluate a composite restorative system based on the now-classic "click" reaction, that is the copper catalyzed azide-alkyne (CuAAC) reaction. Its characteristics include achieving high conversion without side reactions, being robust and readily performed at ambient, and forming a product that is not readily degradable by acids, water, or enzymes. Moreover, the product of the reaction is a triazole ring structure that is capable of secondary molecular interactions (i.e., non-covalen bond formation) that enhance toughness, glass transition, and modulus of the crosslinked polymer material. Thus, this research will address the critical shortcomings of methacrylate composite systems by (i) developing a completely new approach to the resin portion of these composites that implements the CuAAC reaction in a manner that will lead to achievement of near-quantitative functional group conversions, limit extractable monomers, eliminate the potential for hydrolytic and enzymatic degradation, improve the mechanical properties through secondary molecular interactions, and dramatically reduce shrinkage and stress; (ii) combining this novel CuAAC-based resin phase with appropriately functionalized fillers to achieve the desired mechanical performance, improve fracture toughness, extend the lifetime of these restorations, and achieve enhanced dimensional stability of the composite; and (iii) analyzing the adhesion, degradation, extraction, and other long-term performance metrics for these resins and composites. The photo-induced CuAAC polymerization system is ideally suited for the next generation of dental restoratives and our goal is the development of a composite system that is compatible with current dental practices and adhesives and yet yields at least a two fold increase in the service life of these restoratives.