Harshitha Gowda B H, Satish Babu C L
Department of Prosthodontics, M. S. Ramaiah Dental College and Hospital, M. S. R. I. T. Post, Bangalore, Karnataka, India.
Indian J Dent Res. 2013 Mar-Apr;24(2):178-82. doi: 10.4103/0970-9290.116673.
The goal of every prosthetic management is to simulate nature and be in harmony with nature within the physiological limits. The occlusal forces on a fixed dental prosthesis are transmitted to the surrounding structures through pontics, connectors and retainers and more stresses are seen at the connector region. To analyze the stress patterns in cast and soldered connectors between the two pontics and between the retainer and pontic of a four unit fixed dental prosthesis on axial and non axial loading and also to observe and ascertain the need to modify the design of the rigid connectors.
Subsequently four models each of cast and soldered connectors with cylindrical and triangular design, of dimension 3 × 4 mm and thickness 0.5 mm was designed for the study. The first premolar and second molar were considered as the abutments and 2 nd premolar and 1 st molar as the pontics. The analysis was done using ANSYS version 8.0 software and by placing axial and non-axial load of 40 Newtons each.
Von Misses stresses were observed at the connector region between the two pontics, especially in the cervical region.
The cylindrical cast connectors showed less stress in comparison to triangular design and the difference in the stress distribution of cast and soldered connectors were marginal.
The occlusal forces on a fixed dental prosthesis are transmitted to the surrounding structures through pontics, connectors and retainers with maximum stresses concentrated at the connectors. Hence this three-dimensional finite element analysis study investigated stress distribution in a four unit posterior fixed dental prosthesis, having cylindrical and triangular connector designs.
每种修复治疗的目标都是在生理限度内模拟自然并与自然和谐相处。固定义齿上的咬合力量通过桥体、连接体和固位体传递至周围结构，连接体区域会承受更多应力。分析四单位固定义齿的两个桥体之间以及固位体与桥体之间铸造和焊接连接体在轴向和非轴向加载时的应力模式，并观察和确定是否需要修改刚性连接体的设计。
随后设计了四个模型，分别为圆柱形和三角形设计的铸造和焊接连接体，尺寸为3×4毫米，厚度为0.5毫米用于该研究。将第一前磨牙和第二磨牙作为基牙，第二前磨牙和第一磨牙作为桥体。使用ANSYS 8.0软件进行分析，并分别施加40牛顿的轴向和非轴向载荷。
在两个桥体之间的连接体区域观察到冯·米塞斯应力，尤其是在颈部区域。
与三角形设计相比，圆柱形铸造连接体的应力较小，铸造和焊接连接体的应力分布差异不大。
固定义齿上的咬合力量通过桥体、连接体和固位体传递至周围结构，最大应力集中在连接体处。因此，这项三维有限元分析研究调查了具有圆柱形和三角形连接体设计的四单位后牙固定义齿的应力分布。
