INVESTIGATIONS ON THE DEFORMATION AND STRESS DISTRIBUTIONS CONCERNING DENTURES TAKING INTO ACCOUNT THE CONTACT BETWEEN MUCOUS MEMBRANE AND DENTURES

本文对义齿与口腔粘膜接触时的变形进行了研究，得到了以下结果：1.建立了模拟义齿在压力作用下粘膜变形的分析模型。在这些模型中，考虑了剪切变形和液体组分的流动，这使得我们能够模拟在压痕试验情况下观察到的载荷-变形关系的面积依赖性的影响。从计算机模拟结果可以看出，粘膜表面的突起必须发生在凹陷区附近。因此，我们认为新鲜身体的印象是没有压力的情况，而是施加强大压力的情况。通过非接触式位移计对石膏模型表面的检测，验证了上述现象。并进行了实验研究。我们使用石膏和硅酮RTY橡胶制作模型，其中安装了微型压力传感器。传感器的测量数据给出了树脂压头下的压力分布。在橡胶和树脂表面平整且适合性好的情况下，我们发现树脂板的刚性影响很小。得到的压力分布与简单的线性弹簧模型有很大的不同。在义齿表面存在不适合性的情况下，我们发现极少量的不平整度对压力分布有显著的影响。

We study here the deformation of roal mucous membrane and dentures in contact, and obtained the following results:1. The analytical models which simulates the deformations of mucous membrane under pressure induced by dentures are developed. In these models the shearing deformation and the flow of the liquid components are considered, and which enable us to simulate the effects of the area dependency of the load-deformation relationships observed in case of indentation testings.2. From the computer simulations, it is concludes that the protrusion of mucous membrane surface must be take place at the vicinity of the indented area. Hence we take the impressions from fresh cadavers for the cases of pressures are absent and the cases of strong pressures being applied. By detecting the surface of plaster models by the non-contacting displacement gauge, we could certificate the above mentioned tenomena.3. Experimental investigations are also carried out. We make models utilizing plaster and silicone RTY rubber, in which miniature pressure sensors are mounted. The measured data from sensors give the pressure distributions under the resin indenters. In the cases of both surfaces of rubber and resin are flat and fitness is good, we found that the effects of the rigidity of the resin plate is small. The pressure distributions obtained are quite different from the simple linear spring models.4. In the cases that there exists some unfitness on the surfaces, which corresponds to the ill-fitted dentures, we found that the Very small amount of unflatness significantly affects the pressure distributions.