功能化高反应活性POSS的合成及其改性口腔复合树脂的应用基础研究

Composite resin is getting increasingly popular in dental restorative treatments. However, secondary caries after restoration is recognized as one of the major reasons for the failure of resin-based restorations. Polymerization shrinkage and the resultant stress generation related to conventional composite resins, which can lead to marginal microleakage and staining, postoperative sensitivity and secondary caries, is recognized as one of primary reason for the failure of resin-based restorative. Modification of resin matrix with novel functional monomer is a promising strategy to solve the problem. Previousely, we successfully synthesized an expanding monomer and confirmed its effect in reducing polymerization shrinkage.We also synthesized several QAS monomers and confirmed its antibacterial effects. In the present research, to achieve modified composite resins with further improved properties, we are planing to synthesize novel SOC-POSS and QAS-POSS monomers and use them in combination to modify traditional resin. The microstructure, physichemical properties and biocompatibilities of the POSS modified composite resins will be studied, and the bonding properties and occurance of microleakage will be investigated both in vitro and in vivo by using extracted teeth and animal model. This study will provide a new strategy to improve the durability of resin-based restoratives.

继发龋是造成口腔树脂粘接修复失败的首要原因。功能单体改性是减少树脂聚合收缩，赋予其抗菌性能，改善口腔树脂临床修复效果的重要手段。但是我们前期研究发现，功能单体的大量添加，会导致树脂基质的聚合交联度不足，影响树脂的机械、生物学等基本性能。多面低聚倍半硅氧烷（POSS）独特的有机-无机纳米杂化特性有望解决这一问题。本研究拟首先合成高反应活性POSS，改性口腔常用树脂，评价其对改性树脂性能和微观结构的影响，探讨其性能改善机制；在此基础上，合成新型功能化高反应活性POSS，替代传统功能单体改性口腔常用复合树脂，在赋予树脂低收缩和抗菌性能的同时，改善树脂的力学、生物学等基本性能；进而，运用离体牙树脂充填模型和动物实验，评价该低收缩抗菌杂化复合树脂预防充填界面微渗漏、减少继发龋发生的效果，为提高口腔树脂材料的临床修复耐久性提供新策略。同时，为POSS材料在其他领域改性聚合物研究提供借鉴。

聚合收缩、机械性能不足、继发龋是造成口腔树脂粘接修复失败的主要原因。功能单体改性是减少树脂聚合收缩，赋予其抗菌性能，改善口腔树脂临床修复效果的重要手段。本研究合成高反应活性 POSS，评价其对改性树脂性能和微观结构的影响，探讨其性能改善机制；在此基础上，合成新型功能化高反应活性 POSS，替代传统功能单体改性口腔常用复合树脂，在赋予树脂低收缩和抗菌性能的同时，改善树脂的力学、生物学等基本性能。研究发现：不同POSS添加方式对改性树脂的性能影响不同，直接混合法添加MI-POSS和高浓度的MA-POSS会造成POSS在树脂基质中的团聚，造成机械等性能的下降；而通过溶剂混合蒸发法可以明显改善MA-POSS在树脂中的分散性，并提高树脂的机械性能以及耐磨性；通过预聚法和静电纺丝的方法都可以提高MI-POSS树脂的分散性，静电纺丝法制备的树脂机械性能最佳。QAS-POSS改性树脂对变形链球菌均有抗菌性能，并且抗菌作用持久。随着QAS-POSS添加浓度的增加，改性树脂的抑菌性能逐渐增强，细菌粘附减少，细胞膜完整性降低。不同比例的SOC/POSS 改性常用口腔复合树脂，随POSS添加比例的增高，树脂的聚合收缩率下降；弯曲强度增加，压缩强度和吸水值无明显变化。改性实验树脂具有较低的聚合收缩率和较好的机械性能，能够预防树脂修复后微渗漏的效果，具有良好的应用前景。

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