基质填料协同增强牙科光固化复合树脂性能的多尺度研究

Secondary caries occurs in the teeth after the filling restoration with composite resin. Its essence is polymerization shrinkage during the curing process inevitably. Eliminating or reducing the volumetric shrinkage during polymerization and avoiding the occurrence of secondary caries are important issues and research hotspots in the development of dental composites. Many international companies and research institutions are focused on the volume shrinkage, and accordingly developed a preliminary low-shrinkage of products and findings. In previous studies, synthesis of unsaturated spiroorthoester, expansion polymerization and dental composites combined expanding monomer and matrix resin were studied. In this study, a novel dental composite resin is proposed for the first time, which is composed of unsaturated spiroorthocarbonate, bisphenol-S-bis(3-methacrylato-2-hydroxy propyl)ether and nano-magnesia inorganic filler. The resins expected can significantly reduce the volumetric shrinkage and incidence of secondary caries, improve the adhesion of the material and dental tissue, improve the color stability, surface polishing, mechanical strength of prosthesis. The findings will have broad application prospects and give a good therapeutic effect especially for caries and caries prevention, dental defects, repair of anterior aesthetics, post and core restoration, fixed prosthesis, etc. It will provide more evidence and ways for the development of dental biomaterials.

继发龋好发于复合树脂充填后的牙齿。其本质是复合树脂聚合过程中不可避免的体积收缩。降低复合树脂的体积收缩率和避免树脂修复后继发龋的发生一直是牙科临床亟待解决的重要难题和热点研究领域。国际众多企业和研究机构聚焦在体积收缩率和抗菌性这两个主要指标上，并相应开发了相应的产品系列。本课题在前期对含螺环原酸酯膨胀单体的牙体复合材料研究基础上，首次提出由特定的新型四氧螺环烷膨胀单体、含砜基与烯键的双酚-S型树脂和纳米氧化镁无机填料等组成的牙体复合材料的研究。固化后的复合树脂预期可获得较低的聚合性体积收缩率，降低继发龋的发生率，显著提高材料与牙体组织的粘接性和密合性，明显提高修复体的色泽稳定性、表面抛光性、机械强度。研究结果将具有广阔的应用前景和形成产品雏形，特别是对龋病防治、牙体缺损修复、前牙美学修复、桩核修复、固定修复等有着良好的治疗效果。将为口腔生物材料的研究开发提供更多的证据，并开辟一个新的途径。

光固化复合树脂在牙科临床中应用极为广泛。继发龋好发于复合树脂充填后的牙齿。降低复合树脂的聚合性体积收缩和赋予材料良好的抗菌性从而避免树脂修复后继发龋的发生一直是牙科临床亟待解决的重要难题和热点研究领域。纳米技术在龋齿防治中的应用是预防和治疗龋齿的一个前沿方向。本课题在前期对含螺环原酸酯膨胀单体的牙体复合材料研究基础上，首次提出由特定的新型四氧螺环烷膨胀单体、含砜基与烯键的双酚-S型树脂和纳米氧化镁无机填料等组成的牙体复合材料的研究。在三元光敏引发体系下，含膨胀单体的新型树脂能够发生共聚；其体积收缩率大大降低，机械性能提高，并具有较高的接触角和可接受的生物相容性。将纳米氧化镁引入树脂体系中，研究发现纳米氧化镁赋予树脂复合材料优良的抗菌性能，并提高了其耐磨性，良好的抗牙菌斑生物膜性能和生物相容性；通过初步探索镁离子的释放规律发现镁离子的浓度可在一定时间内保持较高的水平，但是否达到杀菌浓度有待进一步研究。通过同时引入纳米氧化镁和膨胀单体构成的基质填料协同增强体系，获得新型牙科光固化复合树脂，研究发现纳米氧化镁可赋予该新型低收缩复合树脂良好的抗菌性能。但纳米氧化镁的团聚、长期抗菌效果、力学性能的改善及抗菌机理有待进一步研究。研究结果为口腔生物材料的研究开发提供更多的证据和思路。