Load Transfer of abutment tooth with post and core for Various mandibular distal extension cases with diminished periodontal support

本研究采用准三维光弹法、高速光弹实验法和有限元法研究了基于RPI系统、Konus Krone系统和支臂系统的三种固位器配置对双侧和单侧远端牙周支持减少病例的牙髓和非牙髓基牙应力分布的影响。建立了单侧和双侧无牙下颌第二前磨牙远端复合光弹模型。对牙周受损患者的牙齿结构、牙周韧带和牙槽骨分别采用不同的模拟材料。为牙齿铸了三个固位器。分别制作了三种固位体设计的单侧和双侧义齿，分别为RPI系统、Konus Krone系统和支臂系统。在义齿上施加模拟的垂直和侧向咬合载荷，并对支撑体中产生的应力进行光弹性监测。结果，下面的内容变得很清楚。1)三种系统的基牙和周围组织的应力分布模式存在差异。2) RPI系统在5个方向上的应力分布最均匀，而Konus Crone系统在垂直、后向和口腔方向上的应力分布较好，支撑臂在前向和舌向上的应力分布较好。3)牙周支持最少的基牙，水平缺损35%，应力浓度最高。增加固定牙齿的数量并没有提供最大应力水平的比例降低。4)无牙髓后金属核基牙的应力浓度较高。5)采用不同尺寸的螺杆进行侧凝根管充填所产生的应力不同。准三维光弹性法与有限元法的计算结果基本一致。少

The purpose of this study was to investigate the stress redistribution in the pulp and non-pulp abutments in bilateral and unilateral distal extension cases with reduced periodontal support of three retainers device configurations based on the RPI system, Konus Krone system, and Bracing arm system using Quasi-three-dimensional Photoelastic method, High-speed Photoelastic Experimental Method and Finite Element Method.Three composite photoelastic models were made of a mandible unilaterally and bilateral edentulous distal to the second premolars. Individual simulant materials were used for tooth structure, periodontal ligament, and alveolar bone of periodontally compromised. Three retainers were cast for the teeth. Unilateral and bilateral partial dentures with three retainer designs, RPI system, Konus Krone system and Bracing arm system were made for the three models. Simulated vertical and lateral occlusal loads were applied to the dentures, and the stresses which developed in the suppo … More rting structures were monitored photoelastically.As a results, it's became clear the following. 1)The stress redistribution patterns in the abutments and surrounding tissues differed between the three systems. 2)The RPI system configurations showed the most uniform redistributions across loads directed in all five directions, while Konus Crone systems showed favorable stress redistribution for vertically, posteriorly, and buccally directed loads and Bracing arms configurations showed favorable stress redistribution for anteriorly and lingually directed loads. 3)the highest stress concentrations were seen in the abutment with the least periodontal support : the 35% horizontal defect. Increasing the number of splinted teeth did not provide a proportional decrease in maximum stress levels. 4)higher stress concentrations were seen in the abutment of non-pulp with post metal core. 5)The differents stress developed by lateral condensation root canal filling using various sizes spreddar. 6)it's became same results both Quasi-three-dimensional Photoelastic Method and Finite Element Method. Less