Doctoral student, The French Institute of Science and Technology for Transport, Development and Networks (IFSTTAR) Laboratory of Applied Biomechanics, Aix-Marseille University, Marseille, France; Research Engineer, Glad Medical SAS, Salon-de-Provence, France.
Doctoral student, The French Institute of Science and Technology for Transport, Development and Networks (IFSTTAR) Laboratory of Applied Biomechanics, Aix-Marseille University, Marseille, France; Associate Professor, Department of Oral Health, National University of Colombia (Facultad de Odontologia Universidad Nacional de Colombia-Bogota), Bogota, Colombia.
J Prosthet Dent. 2019 Mar;121(3):546.e1-546.e10. doi: 10.1016/j.prosdent.2018.09.023. Epub 2019 Jan 31.
Implant-supported overdentures (IODs) are a treatment option for patients with complete edentulism. However, this treatment increases the possibilities of peri-implant complications, characterized by inflammation or partial loss of surrounding hard and soft tissues.
The purpose of this finite element analysis study was to evaluate the mechanical performance of different bar-IOD designs under different clinical configurations by comparing the stress and strain distribution on the bone during secondary stabilization.
A finite element model of the mandible representing a patient with complete edentulism was developed. Different designs of bar-IODs were modeled and compared. The parameters studied were the material properties (cobalt-chromium, zirconium dioxide, titanium grade 5, and titanium grade 4), diameter and bar-IOD cross-sectional shape, tilt of the posterior implants (30 degrees), presence of a distal extension cantilever in the bar-IODs (12 mm), and number of implants (4 or 6). Two different mastication loading conditions were analyzed. One- and 2-way ANOVAs and the Tukey honestly significant differences post hoc test (α=.05) were used to determine the significant von Mises stress and strain values in the bone.
The 4 materials tested in the bar-IOD did not have a significant mechanical effect on the bone (P<.05). A smaller diameter and structure of the bar-IOD led to significantly higher bone stress (P<.001). A distal extension cantilever led to an increased stress concentration (model M1 versus model M3: P<.001), which reached 50% in the event of tilting of the posterior implants (model M2 versus model M4: P<.001). Tilting of the posterior implants alone, without extension, had a nonsignificant effect (model M3 versus model M4: P=.999). Model M5 supported with 6 implants reduces the stress transferred to the bone compared with model M3 supported with 4 implants (P<.05).
Distal extensions in bar-IODs, the tilt of the posterior implants, and the low amount of material in the cross-sectional area in the bar-IOD were the most influential parameters on the mechanical resistance of dental implants in the mandibular bone.
种植体支持的覆盖义齿（IOD）是治疗完全无牙颌患者的一种选择。然而，这种治疗方法增加了种植体周围并发症的可能性，其特征是炎症或周围软硬组织的部分丧失。
本有限元分析研究的目的是通过比较二次稳定过程中骨上的应力和应变分布，评估不同杆式 IOD 设计在不同临床配置下的机械性能。
开发了一个代表完全无牙颌患者的下颌骨有限元模型。对不同的杆式 IOD 设计进行了建模和比较。研究的参数包括材料特性（钴铬、二氧化锆、钛 5 级和钛 4 级）、直径和杆式 IOD 横截面形状、后牙种植体的倾斜度（30 度）、杆式 IOD 中是否存在远中延伸悬臂（12 毫米）以及种植体数量（4 或 6 个）。分析了两种不同的咀嚼加载情况。使用单向和双向方差分析以及 Tukey 诚实显著差异事后检验（α=.05）来确定骨中显著的 von Mises 应力和应变值。
在杆式 IOD 中测试的 4 种材料对骨没有显著的机械影响（P<.05）。较小的直径和杆式 IOD 的结构导致骨上的应力显著增加（P<.001）。远中延伸悬臂导致应力集中增加（模型 M1 与模型 M3：P<.001），而后牙种植体倾斜时达到 50%（模型 M2 与模型 M4：P<.001）。仅倾斜后牙种植体而不延伸没有显著影响（模型 M3 与模型 M4：P=.999）。与用 4 个种植体支撑的模型 M3 相比，用 6 个种植体支撑的模型 M5 可减少传递到骨的应力（P<.05）。
杆式 IOD 中的远中延伸、后牙种植体的倾斜以及杆式 IOD 横截面积中的低材料量是对下颌骨中牙种植体机械阻力影响最大的参数。
