THE DEVELOPMENT STUDY FOR DENTAL RESTORATIVE RESIN WIHT A GOOD ADAPTABILITY BY USE OF EXPANDABLE MONOMER

丙烯酸树脂因其操作简便、美观、化学稳定性好等优点，广泛应用于牙科牙齿修复。然而，聚合过程中的体积收缩往往会在牙科修复体中产生较大的累积应力，从而导致修复体的不准确和变形以及粘结强度的降低。为此，我们合成了几种新的含侧链螺环原酸酯（SOE）和乙烯基的单体和聚合物，并对它们的聚合进行了研究，以开发一种性能优良的修复树脂体系：1）（甲基）丙烯酸酯（ASOE ; 2-acryloxymethyl-1- 1，4，6-trioxaspiro[4.6]undecane，MASOE ; 2-甲基丙烯酰氧基甲基-1，4，6-三氧螺[4.6]十一烷）。2）在热聚合（HC）过程中，以（甲基）丙烯酸和环氧溴丙烷为原料，通过环己内酯与（甲基）丙烯酸的反应，合成了（甲基）丙烯酸和（甲基）丙烯酸（甲基）丙烯酸（甲基）三氧螺[4.6]十一烷以苄基锍盐为离子引发剂，将两个官能团分别与MASOE和甲基丙烯酸酯（MMA）共聚，得到了聚合收缩率小于常规甲基丙烯酸酯的类塑料聚合物。在MMA和共聚物的粉/液聚合中，通过SOE和乙烯基聚合的交联反应，使聚合物具有与PMMA相似的力学性能和较小的聚合收缩率。4）在离子引发剂作用下的ASOE的汞灯光聚合中，既观察到了SOE中的交联反应，也观察到了乙烯基的聚合。通过与离子型引发剂和光敏剂的联合使用，不仅提高了聚合反应的速率，而且提高了聚合反应的程度，证实了同时具有SOE结构和乙烯基的（甲基）丙烯酸酯可以改善牙科修复树脂的聚合收缩。

Acrylic resin are widely used in dentistry for tooth restoration because of its ease in manipulation, aesthetic characteristics and chemical stability. However, its volume shrinkage during the polymerization often causes a large buildup stress in dental restoration and it results in inaccuracy and deformation of the restoration and decrease of bond strength. There-fore, we have synthesized several newmonomers and polymers with pendant spiro ortho ester(SOE) and vinyl group, and studied on the polymerization ofthem in order to develope an excellent restorative resin system :1) (Meth)acrylates(ASOE ; 2-acryloxymethyl-1-1,4,6-trioxaspiro[4.6]undecane, MASOE ; 2-methacryl-oxymethyl-1,4,6-trioxaspiro[4.6]undecane) were synthesized from (meth)acrylic acids acid and the reaction product of epibromohydrine and epsilon-caprolacton.2) In the heat polymerization(HC) of these monomers with benzylsulfonium salts as ionic initiator two functional groups, respectively, reacted and plastic-like polymers which have less polymerization shrinkage than those of conventional methacrylates.3) The copolymers with MASOE and methacrylate(MMA) having pendant SOE moiety and an excellent solubility in MMA were synthesized. In the powder/loquid polymerization(HC) with MMA and the copolymers, it was made the polymers having similar mechanical property and less polymerization shrinkage than those of PMMA by the crosslinking reaction in SOE and vinyl polymerization.4) In the photo-polymerization of ASOE with ionic initiators using Hg-Xe lamp, both the reaction in SOE and the polymerization of vinyl group were observed. By the combined use with ionic initiator and photo-sensitizer it was improved not only the rate of reaction but also the extent of polymerization.As results discrived above, we confirmed that such (meth)acrylates with both the SOE moiety and vinyl group can be improved the polymerization shrinkage of dental restorative resin.