Permanence property of denture base soft lining materials and its evaluation method

研究了四种类型（丙烯酸、氟和烯烃）义齿基托软衬材料的粘弹性随时间的变化，并讨论了其材料在某些试验条件下的耐久性。此外，还研制了一种新的硬度测试仪，用于测量软组织和软衬材料的硬度。该试验装置对推进目前的研究非常有用。结果表明：(1)对亚克力软衬材料进行搅拌时，混合料中含有大量小气泡。随着时间的推移，这些气泡逐渐增大，对固化材料的粘弹性性能产生不良影响。此外，气泡将加速材料对溶剂（如过氧化氢溶液）的粘弹性性能的恶化。(2)丙烯酸和硅酮材料比氟材料更容易受到义齿清洁剂的影响。这些固定材料的表面受到它们的作用而容易失去光泽。(3)软衬材料中包含的增塑剂，如乙醇，被简单地洗脱到水中，在丙烯酸软衬材料中，增塑剂的洗脱明显地恶化了固化材料的粘弹性。(4)丙烯酸和硅酮软衬材料内衬义齿基托树脂的动态储存模量（E′）随测试温度的升高而略有下降。(5)所研制的硬度计适用于口腔软组织及软衬材料的粘弹性测试。

The variation in viscoelastic properties for four types(acrylic, fluoric and olefine) of the denture base soft lining materials were examined with time elapsed and the durability of their materials under the some test conditions was discussed. In addition, a new hardness tester was developed for measuring the hardness of the soft tissue and the soft lining materials. This trial tester was very useful to advance the present investigation.The results obtained were as follows: (1) In case an acrylic soft lining material is manipulated, small air bubbles are much contained in the mixture during mixing. And these air bubbles gradually increase with time elapsed and will have a bad influence on viscoelastic properties of the set materials. Furthermore, the air bubbles will accelerate the deterioration of the viscoelastic properties of the materials against the solvent, such as a hydroperoxide solution. (2) Acrylic and silicone materials are more susceptible to the denture cleaners than the fluoro material. The surface of these set materials is attacked by an action of them and is easily tarnished. (3) An plasticizer included in the soft lining materials, such as ethanol, is simply eluted into water and in the acrylic soft lining materials, the elution of the plasticizer deteriorates markedly the viscoelastic property of the set material. (4) The dynamic storage modulus (E') of the denture base resin lined with the acrylic and silicone soft lining materials decreased slightly depending on the increase in temperature tested. (5) The developed hardness tester was found to be suitable for examining the viscoelastic properties of oral soft tissue and soft lining material.