Methods of imparting the Functional Gradient to Some Dental Adhesives

在牙科粘合剂和胶合剂中，玻璃离子聚合物胶合剂由聚酸和固体颗粒组成。已经证明可以通过在一个方向上产生成分梯度来赋予它们功能梯度。在本研究中，采用由聚丙烯酸（PAA）和玻璃颗粒组成的简化体系来代表玻璃离子聚合物水泥体系。通过观察浊度的变化，研究了不同粒径玻璃颗粒作为模型填料在重力作用下的沉降特性。沉降速度主要取决于(1)共存聚合物在介质中的膨胀，(2)聚合物的浓度，(3)分散颗粒的大小。进一步研究不同类型助熔剂的混合效果、离子强度或粘度等因素对助熔剂的影响将有助于本研究的进一步发展。通过这些研究，人们非常希望揭示沉积是如何形成的，它描述了任意点的成分梯度或成分，作为时间，填料尺寸等的函数。另一种可能产生复合梯度的方法，即对粘合剂系统中有关的带电组分进行电泳，也将进行研究。附属调查结果如下。1)荧光距离探针可以有效地发现paa的构象；2)差示扫描量热法可用于研究粘附-牙蛋白的相互作用。3)研制出了全自动滴定系统，在许多方面具有潜在的适用性。这些额外的发现也将有助于发展牙科材料的研究。

Among dental adhesives and cements, glass-ionomer cements consist of polyacids and solid particles. It has been shown possible to impart them a functional gradinet by generating a compositional gradient in one direction. In the current study, a simplified system consisting of polyacrylic acid (PAA) and glass particles was employed to represent a glass-ionomer cement system. The sedimentation properties of glass particles with various size, as the model fillers, were investigated under the gravity by observing the change in the turbidity. Sedimentation velocity was mainly dependent on (1) the expansion of co-existing polymers in the media, (2) the concentration of polymers, (3) the size of the dispersed particles. Further invesigation of the mixing effects of the flliers of different type, the effects of ionic strength or viscosity, etc.will help to develope this study. Through these studies, it is highly expected to reveal how the sedimentation is formulated, which describes the compositonal gradient or a composition at all arbitrary point, as a function of time, filler size and so on. Another possible way of generating a compositoinal gradient, an electrophoresis of charged components concerned in the adhesive systems, is also to be examined.Subsidary findings are as follows.1) Fluorescent distance probe was effectively used to find out the conformation of PAA.2) Differential scanning calorimetry was useful in the investigation of adhesive-tooth protein interaction.3) Full-automatic titration system has been developed, which has potintial applicability to many aspects.Those extra findings will also help developing the study of dental materials.