【摘要】 <正> 一、前言当人体(或其它动物)受外界猛烈碰撞会造成断裂(骨折)、肌肉扭伤等,这些现象产生都与力学有关。根据近来研究可知:生物体上所受局部应力在一定范围内时,可促使该部分机体生长;而当局部应力超过某一范围时,生物体会象工程零件一样发生断裂破坏。因此,用力学理论和实验来进行生物体应力分析很有必要。生物体和工程零件材质上是有区别的。首先它不是各向同性材料,具有明显的各向异性性质。其次,它是变截面材料,又是有不同力学性质的骨密质等部分组成。用力学理论来计算会比工程零件的计算带来更大困难,仍至无法进行。目前,日益使用实验方法解决生物体的应力分析。本文是对人体口腔天然牙(人牙)缺失后,以不同(牙合)支托形式按装假牙(义齿)时,用光弹性实验方法测定义齿受力时由(牙合)支托传递至天然牙牙根处应力。同时研究了不同(牙合)支托形式对应力的影响。二、牙体结 构更多还原

【Abstract】 The photoelastic technique of experimental stress analysis is an effective means to identify and demonstrate the stress distribution of a partially edentulous mandible. To utilize photoelastic technique, models of both the bony portion and the tooth structure of a mandible are made with epoxy plastic, as shown in Fig. 1. The stress distributions of two occlusal rests (distal and mesio-occlusal rest ) are compared by using one photoelastic model. Both the stress fringes and the trajectories of equal stress for two occlusal rests are shown in Figs. 3, 4, 5 and 6 for the models of two partially edentulous mandibles. The experiments concerning two occlusal rests are made by using freeze technique, and the load applied on first molar is inclined at an angle of 30°to long axis of denture in anterior, posterior, buccal and lingual directions. From the experimental investigations, the author makes the following observation: The stresses for mesio-occlusal rest are less than those for distal occlusal rest; the more closely the line of action of vertical force approaches the abutment tooth, the greater are the stresses of abutment tooth region and the smaller are the stresses of denture base.更多还原