Department of Prosthodontics, Aracatuba School of Dentistry, UNESP- Sao Paulo State University, Sao Paulo, Brazil.
Int J Oral Maxillofac Implants. 2010 Nov-Dec;25(6):1108-14.
The purpose of this study was to evaluate the influence of different types of bone on the stress distribution in the mandibular bone supporting a prefabricated bar-type implant prosthesis using three-dimensional finite element analysis.
Four finite element models (M) of a completely edentulous mandibular arch were built. The bone types varied from type 1 to type 4 (M1, M2, M3, M4). The arch was restored using a prefabricated bar system supported by four interforaminal implants for the protocol prosthesis. Computer software was used to determine the stress fields. Three unilateral posterior loads (L) of 150 N were exerted on the prosthesis: L1, perpendicular to the prefabricated bar; L2, oblique (30 degrees) in the buccolingual direction; and L3, oblique (30 degrees) in the linguobuccal direction. The maximum principal stress (Omax) and the maximum principal strain (Emax) were obtained for cortical and trabecular bone.
Types 3 and 4 bone showed the highest smax (MPa) in the cortical bone (19.9 and 18.2 for L1, 34.6 and 31.3 for L2, and 3.88 and 24.4 for L3, respectively). The maximum principal strain (Emax) was observed in type 4 cortical bone for all loads (1.80 for L1, 2.4 for L2, and 2.36 for L3).
The cortical bone in M3 and M4 showed the highest stress concentration in the axial and buccolingual loading conditions. Bone types 1 and 2 showed the lowest stress concentrations. For the linguobuccal loading condition, the cortical bone in M4 showed the highest stress concentration, followed by bone types 3, 2, and 1. Cortical bone in M4 showed the highest strain for all loading conditions. The bone type might not be the only decisive factor to influence the stress distribution the bone supporting an implant prosthesis anchored by a prefabricated bar.
本研究旨在通过三维有限元分析评估不同类型的骨对上颌骨支持预制杆式种植体修复体的应力分布的影响。
构建了四个完全无牙颌弓的有限元模型（M）。骨类型从 1 型到 4 型（M1、M2、M3、M4）不等。该弓使用由四个眶间植入物支撑的预制杆系统进行修复，以支持协议修复体。计算机软件用于确定应力场。在修复体上施加三个单侧后向载荷（L），分别为 150N：L1，垂直于预制杆；L2，颊舌向斜向（30°）；L3，舌颊向斜向（30°）。获得皮质骨和小梁骨的最大主应力（Omax）和最大主应变（Emax）。
类型 3 和 4 的皮质骨的 smax（MPa）最高（L1 时分别为 19.9 和 18.2，L2 时为 34.6 和 31.3，L3 时为 3.88 和 24.4）。所有载荷下，最大主应变（Emax）均见于 4 型皮质骨（L1 时为 1.80，L2 时为 2.4，L3 时为 2.36）。
在轴向和颊舌加载条件下，M3 和 M4 的皮质骨表现出最高的应力集中。1 型和 2 型骨表现出最低的应力集中。对于舌颊向加载条件，M4 的皮质骨表现出最高的应力集中，其次是 3 型、2 型和 1 型。对于所有加载条件，M4 的皮质骨表现出最高的应变。骨类型可能不是影响预制杆式种植体修复体骨支持的骨的应力分布的唯一决定性因素。
