de Souza Batista Victor Eduardo, Verri Fellippo Ramos, Almeida Daniel Augusto de Faria, Santiago Junior Joel Ferreira, Lemos Cleidiel Aparecido Araújo, Pellizzer Eduardo Piza
a Graduate Program in Dentistry, Department of Dental Materials and Prosthodontics , Araçatuba Dental School, UNESP - Univ Estadual Paulista , Araçatuba , Brazil.
b Department of Dental Materials and Prosthodontics, Araçatuba Dental School , UNESP - Univ Estadual Paulista , Araçatuba , Brazil.
Comput Methods Biomech Biomed Engin. 2017 May;20(6):663-670. doi: 10.1080/10255842.2017.1287905. Epub 2017 Feb 13.
The aim of this study was to evaluate the influence of pontic and cantilever designs (mesial and distal) on 3-unit implant-retained prosthesis at maxillary posterior region verifying stress and strain distributions on bone tissue (cortical and trabecular bones) and stress distribution in abutments, implants and fixation screws, under axial and oblique loadings, by 3D finite element analysis. Each model was composed of a bone block presenting right first premolar to the first molar, with three or two external hexagon implants (4.0 × 10 mm), supporting a 3-unit splinted dental fixed dental prosthesis with the variations: M1 - three implants supporting splinted crowns; M2 - two implants supporting prosthesis with central pontic; M3 - two implants supporting prosthesis with mesial cantilever; M4 - two implants supporting prosthesis with distal cantilever. The applied forces were 400 N axial and 200 N oblique. The von Mises criteria was used to evaluate abutments, implants and fixation screws and maximum principal stress and microstrain criteria were used to evaluate the bone tissue. The decrease of the number of implants caused an unfavorable biomechanical behavior for all structures (M2, M3, M4). For two implant-supported prostheses, the use of the central pontic (M2) showed stress and strain distributions more favorable in the analyzed structures. The use of cantilever showed unfavorable biomechanical behavior (M3 and M4), mainly for distal cantilever (M4). The use of three implants presented lower values of stress and strain on the analyzed structures. Among two implant-supported prostheses, prostheses with cantilever showed unfavorable biomechanical behavior in the analyzed structures, especially for distal cantilever.
本研究的目的是通过三维有限元分析，评估上颌后牙区3单位种植固定义齿中桥体和悬臂设计（近中及远中）对骨组织（皮质骨和松质骨）应力和应变分布以及基牙、种植体和固定螺钉应力分布的影响，分析轴向和斜向载荷作用下的情况。每个模型由包含右侧第一前磨牙至第一磨牙的骨块组成，带有三个或两个外六角种植体（4.0×10 mm），支持一个3单位联冠式固定义齿，有以下几种变体：M1 - 三个种植体支持联冠；M2 - 两个种植体支持带有中央桥体的义齿；M3 - 两个种植体支持带有近中悬臂的义齿；M4 - 两个种植体支持带有远中悬臂的义齿。施加的力为轴向400 N和斜向200 N。采用冯·米塞斯准则评估基牙、种植体和固定螺钉，采用最大主应力和微应变准则评估骨组织。种植体数量的减少对所有结构（M2、M3、M4）产生了不利的生物力学行为。对于两个种植体支持的义齿，使用中央桥体（M2）在分析的结构中显示出更有利的应力和应变分布。使用悬臂显示出不利的生物力学行为（M3和M4），主要是远中悬臂（M4）。使用三个种植体在分析的结构上显示出较低的应力和应变值。在两个种植体支持的义齿中，带有悬臂的义齿在分析的结构中显示出不利的生物力学行为，尤其是远中悬臂。
