Postgraduate student, Department of Periodontics, Faculty of Dentistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.
Dentofacial Deformities Research Center, Research Institute for Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Periodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Long Term Eff Med Implants. 2021;31(2):81-89. doi: 10.1615/JLongTermEffMedImplants.2021037917.
Using finite element analysis, this study assesses maximum insertion torque, stress, and strain in bone during insertion of three dental implant types with different macroscopic designs. We model a bone block including cancellous and cortical bones and an osteotomy hole matching the size of the final implant drill. We then model three implants of the same length and diameter but with different thread and body designs. Model I has a conical body with greater apical region tapering and specifically designed threads, model II has wedge-shaped threads and a conical body, and model III is a conical implant with progressive threads. We place models into the bone block at 30 rounds/min and evaluate the implant insertion process in three equal phases of apical, middle, and coronal thirds. We record mean maximum von Mises stress, strain, and insertion torque at 10 points in each third of the osteotomy hole (total of 30 points). In all three implant models, increasing fixture insertion depth into the osteotomy hole results in augmented maximum von Mises stress, strain, and insertion torque in bone. Maximum values are recorded in model I, whereas minimum values are recorded in model III. The dental implant model with crestal microthread design shows maximum von Mises stress, strain, and insertion torque, whereas the model with progressive thread design and absence of coronal threads shows minimum stress, strain, and torque.
本研究采用有限元分析方法，评估了三种宏观设计不同的牙科种植体在植入过程中骨内的最大插入扭矩、应力和应变。我们构建了一个包含松质骨和皮质骨以及与最终种植体钻大小匹配的截骨孔的骨块模型。然后，我们构建了三种长度和直径相同但螺纹和体部设计不同的种植体模型。模型 I 具有较大的根尖区域逐渐变细的锥形体部和专门设计的螺纹，模型 II 具有楔形螺纹和锥形体部，模型 III 是具有渐进螺纹的锥形种植体。我们以 30 转/分的速度将模型放入骨块中，并在根尖、中间和冠部三分之一相等的三个阶段评估种植体的插入过程。我们在截骨孔的每三分之一记录 10 个点的平均最大 von Mises 应力、应变和插入扭矩（共 30 个点）。在所有三种种植体模型中，增加种植体在截骨孔中的插入深度会导致骨内最大 von Mises 应力、应变和插入扭矩增加。最大数值记录在模型 I 中，而最小数值记录在模型 III 中。具有嵴微螺纹设计的种植体模型显示出最大的 von Mises 应力、应变和插入扭矩，而具有渐进螺纹设计且无冠部螺纹的模型则显示出最小的应力、应变和扭矩。
