Development of New Dental Adhesive utilizing MENTA monomer

本研究将甲基丙烯酰氧乙基萘三甲酸酐（MENTA）作为助粘剂应用于牙科胶粘剂中，发现MENTA-126、甲基丙烯酸2-羟乙酯和2.2-双（4-甲基丙烯酰氧聚乙氧基苯基）丙烷的质量分数分别为1.5wt%、48.5wt%和50wt%时，对于化学固化型和光固化型的粘接剂都有较好的增粘效果。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/对甲苯亚磺酸钠）或二元光敏剂（邻苯二酚/甲基丙烯酸2-（N，N-二甲氨基）乙酯）粘接牙釉质，牙本质，其粘接强度分别为140 kgf/cm ~ 2和60 kgf/cm ~ 2。这些粘结强度高于市售牙科胶粘剂所获得的值。一般指出，用酸性溶液预处理牙齿表面是必要的，以获得高粘结强度的牙科胶粘剂。然而，研究发现，预处理并不总是提高粘结强度，特别是对牙本质。扫描电镜断口分析表明，这一现象的原因是树脂渗透层下的脱钙牙本质失效。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。本课题还尝试将MENTA与丙烯酸的共聚物应用于牙科玻璃离子水门汀中。然而，没有获得任何具有实际凝固性能的实验组合物，因为MENTA-丙烯酸共聚物由于其疏水萘环而对水具有非常有限的溶解度。

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.