Borie Eduardo, Orsi Iara Augusta, Noritomi Pedro Yoshito, Kemmoku Daniel Takanori
Int J Oral Maxillofac Implants. 2016 Jan-Feb;31(1):101-10. doi: 10.11607/jomi.4120. Epub 2015 Oct 16.
To evaluate the biomechanical behaviors of multiple implant-supported prostheses with different implant lengths, connections, locations, and restoration materials in the maxillary anterior region using three-dimensional finite element analysis.
A finite element model of a maxillary image was created from a tomography data bank. The simulations were executed in two types of models based on the treatment plan: (1) two implants with 4.0-mm diameters placed in the maxillary central incisors to simulate an implant-supported fixed prosthesis with four elements with a cantilever of both maxillary lateral incisors; (2) two implants with 3.75-mm diameters placed in the maxillary lateral incisors to simulate a conventional fixed prosthesis with four elements with pontics for maxillary central incisors. Subsequently, the models created were subdivided into eight subgroups according to implant length, connection type, and restoration material. A total static oblique load of 150 N was applied to the cingulum area of the palatal surfaces of the four incisors at an angle of 45 degrees to the long axis of the implant in the palatal-labial direction. Bone stresses were analyzed through maximum and minimum principal stresses and ductile material as implant, framework, and abutments were analyzed using von Mises stress criterion.
Regardless of implant diameter and type of treatment, the 8.5-mm-long implants exhibited the lowest tensile and compressive stresses. Maximum and minimum principal stresses were identified in the cortical bone. The lowest von Mises equivalent stress values were identified in the metal-ceramic prostheses, with the exception of the cantilever prosthesis model with flat top connection. Conical cone implant models exhibited maximum von Mises equivalent stress in contact with the abutment.
The lowest principal stresses in the peri-implant bone were observed in implants with conical cone connection and 8.5 mm in length. Also, in most cases, the models with metal-ceramic restorations exhibited better stress distributions.
采用三维有限元分析评估上颌前部区域不同种植体长度、连接方式、位置及修复材料的多种种植体支持式修复体的生物力学行为。
从断层扫描数据库创建上颌图像的有限元模型。根据治疗计划在两种模型中进行模拟：（1）在上颌中切牙植入两颗直径4.0 mm的种植体，模拟由四个部件组成且带有上颌侧切牙悬臂的种植体支持式固定修复体；（2）在上颌侧切牙植入两颗直径3.75 mm的种植体，模拟由四个部件组成且带有上颌中切牙桥体的传统固定修复体。随后，根据种植体长度、连接类型和修复材料将创建的模型细分为八个亚组。在四个切牙腭面的舌隆突区域沿种植体长轴腭 - 唇方向成45度角施加150 N的总静态斜向载荷。通过最大和最小主应力分析骨应力，使用von Mises应力准则分析作为种植体、支架和基台的延性材料。
无论种植体直径和治疗类型如何，8.5 mm长的种植体表现出最低的拉伸和压缩应力。在皮质骨中识别出最大和最小主应力。除平顶连接的悬臂修复体模型外，金属 - 陶瓷修复体中识别出最低的von Mises等效应力值。锥形种植体模型在与基台接触处表现出最大的von Mises等效应力。
在种植体周围骨中，观察到锥形连接且长度为8.5 mm的种植体主应力最低。此外，在大多数情况下，金属 - 陶瓷修复体模型表现出更好的应力分布。
