School of Dentistry, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
Department of Dentistry, University of Taubaté (UNITAU), Taubaté, Brazil.
Dent Mater. 2021 Nov;37(11):1688-1697. doi: 10.1016/j.dental.2021.08.022. Epub 2021 Sep 6.
The aim of this study was to evaluate the influence of three different dental implant neck geometries, under a combined compressive/shear load using finite element analysis (FEA). The implant neck was positioned in D2 quality bone at the crestal level or 2 mm below.
One dental implant (4.2 × 9 mm) was digitized by reverse engineering techniques using micro CT and imported into Computer Aided Design (CAD) software. Non-uniform rational B-spline surfaces were reconstructed, generating a 3D volumetric model similar to the digitized implant. Three different models were generated with different implant neck configurations, namely 0°, 10° and 20°. D2 quality bone, composed of cortical and trabecular structure, was modeled using data from CT scans. The implants were included in the bone model using a Boolean operation. Two different fixture insertion depths were simulated for each implant: 2 mm below the crestal bone and exactly at the level of the crestal bone. The obtained models were imported to FEA software in STEP format. Von Mises equivalent strains were analyzed for the peri-implant D2 bone type, considering the magnitude and volume of the affected surrounding cortical and trabecular bone. The highest strain values in both cortical and trabecular tissue at the peri-implant bone interface were extracted and compared.
All implant models were able to distribute the load at the bone-implant contact (BIC) with a similar strain pattern between the models. At the cervical region, however, differences were observed: the models with 10° and 20° implant neck configurations (Model B and C), showed a lower strain magnitude when compared to the straight neck (Model A). These values were significantly lower when the implants were situated at crestal bone levels. In the apical area, no differences in strain values were observed.
The implant neck configuration influenced the strain distribution and magnitude in the cortical bone and cancellous bone tissues. To reduce the strain values and improve the load dissipation in the bone tissue, implants with 10° and 20 neck configuration should be preferred instead of straight implant platforms.
本研究旨在通过有限元分析（FEA）评估三种不同的牙科种植体颈部几何形状在压缩/剪切复合载荷下的影响。种植体颈部位于牙槽嵴水平或下方 2mm 的 D2 质量骨中。
通过逆向工程技术，使用微 CT 对一个牙科种植体（4.2×9mm）进行数字化，并将其导入计算机辅助设计（CAD）软件。使用非均匀有理 B 样条曲面进行重建，生成类似于数字化种植体的 3D 体积模型。生成了三种具有不同种植体颈部配置的不同模型，即 0°、10°和 20°。使用 CT 扫描数据模拟 D2 质量骨，由皮质和小梁结构组成。使用布尔运算将种植体包含在骨模型中。对每个种植体模拟了两种不同的植入物插入深度：在牙槽嵴骨下方 2mm 和正好在牙槽嵴骨水平。将获得的模型以 STEP 格式导入 FEA 软件。分析了种植体周围 D2 骨类型的 Von Mises 等效应变，考虑了周围皮质和小梁骨的大小和体积。提取并比较了种植体周围骨界面处皮质和小梁组织中应变值最高的部位。
所有种植体模型都能够在骨-种植体接触（BIC）处分布载荷，模型之间具有相似的应变模式。然而，在颈部区域观察到差异：与直颈（模型 A）相比，具有 10°和 20°种植体颈部配置（模型 B 和 C）的模型显示出较低的应变幅度。当植入物位于牙槽嵴骨水平时，这些值显著降低。在根尖区域，应变值没有差异。
种植体颈部配置影响皮质骨和松质骨组织中的应变分布和幅度。为了降低应变值并改善骨组织中的载荷耗散，应优先选择具有 10°和 20 颈配置的种植体，而不是直的种植体平台。
