Graduate student, Dental Research Institute and Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
Graduate student, Department of Prosthodontics, Graduate School of Dentistry, Seoul National University, Seoul, Republic of Korea; Clinical Assistant Professor, Department of Prosthodontics, Dental Hospital, St. Mary's Hospital of Catholic University of Korea, Seoul, Republic of Korea.
J Prosthet Dent. 2019 Nov;122(5):474.e1-474.e8. doi: 10.1016/j.prosdent.2019.04.025. Epub 2019 Oct 4.
Finite element analysis (FEA) has been used to evaluate the biomechanical behaviors of dental implants. However, in some FEA studies, the influence of the preload condition has been omitted to simplify the analysis. This might affect the results of biomechanical analysis significantly. The preload condition requires analysis.
The purpose of this FEA study was to evaluate and verify the effects of the presence of the preload condition on abutment screws under the occlusal load for external and internal hexagonal connection systems.
The finite element models consisting of bone blocks, 2 different implant systems (Osstem US and GS system; Osstem Implant Co), and crowns were created. With these components, a total of 6 models with different conditions were constructed for FEA: external hexagonal connection system only with preload (EO), external hexagonal connection system with no preload but occlusal load (EN), external hexagonal system with both preload and occlusal load (EP), internal hexagonal system only with preload (IO), internal hexagonal system with no preload but occlusal load (IN), and internal hexagonal system with both preload and occlusal load (IP). An 11.3-degree oblique load (100 N) to the axis of the implant was applied on the occlusal surface of the crown for the models with occlusal load. A preload of 825 N was applied in the abutment screw of the models EO, EP, IO, and IP. The maximum von Mises stress, maximum principal stress, and maximum displacement of the components of the models were evaluated.
Both external and internal connection systems resulted in higher maximum von Mises stress and maximum principal stress values in the presence of preload in the abutment screw. The internal connection system showed higher displacement values than the external system with or without occlusal loading, and values tended to increase with the preload condition.
The presence of a preload condition significantly affected the biomechanical behaviors of the components of 2 different connection systems. The preload condition should be included in FEA to achieve more realistic results.
有限元分析（FEA）已被用于评估牙种植体的生物力学行为。然而，在一些 FEA 研究中，为了简化分析，忽略了预紧条件的影响。这可能会显著影响生物力学分析的结果。需要对预紧条件进行分析。
本有限元分析研究旨在评估和验证预紧条件对外部和内部六角连接系统中基台螺钉在咬合载荷下的影响。
创建了由骨块、2 种不同种植体系统（Osstem US 和 GS 系统；Osstem Implant Co）和牙冠组成的有限元模型。使用这些组件，共构建了 6 种具有不同条件的 FEA 模型：仅具有预紧条件的外部六角连接系统（EO）、没有预紧但具有咬合载荷的外部六角连接系统（EN）、具有预紧和咬合载荷的外部六角系统（EP）、仅具有预紧条件的内部六角连接系统（IO）、没有预紧但具有咬合载荷的内部六角连接系统（IN）和具有预紧和咬合载荷的内部六角系统（IP）。对于具有咬合载荷的模型，在牙冠的咬合面上施加 11.3 度斜向（100 N）至种植体轴的载荷。在 EO、EP、IO 和 IP 模型的基台螺钉中施加 825 N 的预紧力。评估了模型各部件的最大 von Mises 应力、最大主应力和最大位移。
在基台螺钉中有预紧力的情况下，外部和内部连接系统都会导致更高的最大 von Mises 应力和最大主应力值。与无咬合载荷相比，内部连接系统的位移值更高，并且随着预紧条件的增加而增加。
预紧条件的存在显著影响了两种不同连接系统组件的生物力学行为。在 FEA 中应包括预紧条件，以获得更真实的结果。
