Light-propelled dental adhesives with enhanced bonding capability

项目概要/摘要： 超过1.22亿的牙科患者反映了对美观复合材料的日益偏好。 然而，失败的替代品占美国每年销售额的50%以上。 所有的牙科修复工作。相对于传统的双稳态，复合双稳态持续时间相对较短 (e.g.,汞合金）归因于弱混合层，该弱混合层是将粘合剂结合到牙齿结构的层。粘结 以一致和稳定的方式固定到牙齿中的牙本质是具有挑战性的。当将粘合剂树脂施加在蚀刻的牙本质上时， 依靠简单的扩散均匀地渗透牙本质小管直到牙髓存在时的蚀刻深度 压力使得对牙本质的粘附更不可预测并且更技术敏感。在混合体中留下暴露的胶原蛋白 层通过使其易受蛋白水解降解而损害其机械强度和长期稳定性。我们 我提出了一个解决这个问题的办法，通过引入光响应，甲基丙烯酸酯纳米添加剂，溶胀和分散 在传统的粘合剂中，并且被设计成远离可见光源。通过使用光致树脂 流动性，我们建议驱动控制，光激活，疏水和亲水的均匀扩散 牙本质小管内的粘合树脂组分直至蚀刻深度。这将确保脱矿物质 表面和暴露的胶原网络现在被混合层内的树脂均匀且均质地包封， 与牙齿形成机械坚固的锚。随后，纳米添加剂表面上的侧基官能团 将通过引入交联进一步增强树脂-牙本质界面的强度和胶原的稳定性 通过初级和次级键。不稳定官能团的存在可以诱导分子间和 微原纤维间胶原交联，沿着疏水相互作用可以增强机械性能， 粘合剂层的生物稳定性。增加的交联还将降低混合层对细菌的易感性。 胶原酶和MMPs。因此，我们将特别致力于1）合成4至6种光响应纳米添加剂， 并研究作为430-480 nm光的函数的粘合剂树脂推进 暴露、聚合动力学、转化度和模拟牙髓压力下的机械性能。 为此，将使用溶液聚合方案合成光响应性纳米添加剂，并将其用于制备光响应性纳米添加剂。 粘合树脂-纳米添加剂网络将基于光响应部分的类型和浓度来表征 在网络中。通过纳米添加剂引入悬垂功能，以增强生物粘附和胶原交联 也将进行评估。在目标2中，我们将建立纳米添加剂可以增强生物粘附的条件 在混合层内通过额外的交联，并表征微TBS，界面间隙的形成，和稳定性， 树脂-牙齿界面在口腔的物理化学环境。

Project Summary/Abstract: The growing preference for aesthetically pleasing composite restorations is reflected in the over 122 million dental restorations placed annually in the U.S. However, the replacement of failed restorations accounts for greater than 50% of all restorative dental work. The relatively short duration composite restorations last in comparison to traditional restorations (e.g., amalgam) is attributed to a weak hybrid layer, which is the layer that bonds the adhesive to the tooth structure. Bonding to dentin in the tooth in a consistent and stable manner is challenging. While applying the adhesive resin on etched dentin, relying on simple diffusion to homogenously infiltrate the dentinal tubules up to the etch depth in the presence of pulpal pressure makes adhering to dentin less predictable and more technique sensitive. Leaving exposed collagen within the hybrid layer compromises its mechanical strength and long-term stability by leaving it vulnerable to proteolytic degradation. We propose a solution to this problem by introducing light-responsive, methacrylated nanoadditives that swell and disperse within conventional adhesives and are designed to move away from a visible light source. By using light-induced resin mobility, we propose to drive the controlled, light-activated, homogenous diffusion of hydrophobic and hydrophilic adhesive resin components within dentinal tubules up to the depth of etching. This will ensure that the demineralized surfaces and exposed collagen networks are now evenly and homogenously enveloped by resin within the hybrid layer to form a mechanically robust anchor with the tooth. Subsequently, pendant functionality on the surface of the nanoadditives will further enhance the strength of the resin-dentin interface and the stability of the collagen by introducing crosslinking via primary and secondary bonds. The presence of labile functional groups that can induce intermolecular and intermicrofibrillar collagen crosslinks, along with hydrophobic interactions can enhance the mechanical properties and biostability of the adhesive layer. Increased crosslinking will also decrease the susceptibility of the hybrid layer to bacterial collagenase and MMPs. Therefore, we will specifically aim to 1) synthesize 4 to 6 light-responsive nanoadditives that can be incorporated within conventional adhesive resins and study adhesive resin propulsion as a function of 430-480 nm light exposure, polymerization kinetics, degree of conversion, and mechanical properties under simulated pulpal pressure. Toward this end, light-responsive nanoadditives will be synthesized using a solution polymerization protocol and the adhesive resin-nanoadditive networks will be characterized based on the type and concentration of light-responsive moieties within the networks. Pendant functionality introduced via nanoadditives to enhance bioadhesion and collagen crosslinking will also be evaluated. In Aim 2, we will establish the conditions by which the nanoadditives can enhance bioadhesion within the hybrid layer via additional crosslinking and characterize the µTBS, interfacial gap formation, and stability of the resin-tooth interface in the oral physiochemical environment.