Development of New Dental Adhesive utilizing MENTA monomer

本研究将甲基丙烯酰氧乙基萘三羧酸酸酐（MENTA）作为一种促粘剂应用于牙胶粘剂中。1.5wt% MENTA-126, 48.5wt% 2-甲基丙烯酸羟乙基酯和50wt% 2.2-双（4-甲基丙烯酰氧聚氧基苯）丙烷的混合物是最适合化学固化和光固化的粘合剂。采用三元氧化还原引发剂（过氧化苯甲酰/N，N-二（2-羟乙基）-对甲苯胺/对甲苯亚硫酸钠）或二元光敏剂（脑醌/2-（N，N-二甲氨基）甲基丙烯酸乙酯），对牙本质的粘结强度分别为140kgf/cm^2和60kgf/cm^2。这些粘结强度高于市场上获得的牙胶粘剂的值。人们普遍认为，为了使树脂粘结剂获得较高的粘结强度，必须用酸性溶液对牙表面进行预处理。然而，我们发现预处理并不一定能提高牙本质的结合强度，尤其是与牙本质的结合强度。扫描电镜断口图表明，这一发现的原因是脱钙牙刚好在树脂浸润层下失效。然后系统地研究了含金属阳离子的酸性溶液对键合的影响。用含铜或铁离子的柠檬酸水溶液或乳酸水溶液均有促进作用。本课题还尝试将MENTA与丙烯酸共聚物用于牙科玻璃离子水门汀。然而，由于menta -丙烯酸共聚物的疏水性萘环，其对水的溶解度非常有限，因此没有得到任何具有实际凝结性能的实验组合物。

In the present research project, methacryloyloxyethyl naphthalenetricarboxylate anhydride (MENTA) was applied to dental adhesive as an adhesion-promoting ingredient.The mixture of 1.5wt% MENTA-126, 48.5wt% 2-Nydroxyethyl methacrylate and 50wt% 2.2-bis(4-methacryloyloxypolyethoxyphenyl)propane was most suitable for both chemically-curable and photocurable abhesives. The bond strenghts of 140kgf/cm^2 for enamel and 60kgf/cm^2 for dentin were obtained by the abhesive using a ternary redox initiator (benzoyl peroxide/N,N-di(2-hydroxyethyl)-p-toluidine/sodium p-toluene sulfinate) or binary photosensitizer (camphorquinone/2-(N,N-dimethylamino) ethyl methacrylate). These bond strengths were higher than the values obtained by dental adhesives on the market.It was generally pointed out that pretreatment of tooth surface with acidic solutions was necessary to obtain high bond strength by a resinous adhesive. However, it was found the cases that the pretreatment did not always enhance the bond strength, especially to dentin. It was demonstrated by scanning electron microscopic fracto-graphy that the cause of this finding was a failure of decalcified dentih just under a resin-infiltrated layer. Then, the effects of acidic solutions containing metal cation on the bonding were systematically investigated. There were the promotive effects when aqueous solution of citric or lactic acid containing cupric or ferric ion was used.In this project, also copolymer of MENTA and acrylic acid was tried to utilize in dental glass ionomer cement. However, any experimental composition having practical setting property was not obtained, because MENTA-acrylic acid copolymer had very limited solubility to water due to its hydrophobic naphthalene rings.