Department of Biomedical, Surgical, and Dental Sciences; Università degli Studi di Milano, Milan, Italy.
IRCCS Istituto Ortopedico Galeazzi, Milan, Italy.
J Oral Implantol. 2023 Jun 1;49(3):323-329. doi: 10.1563/aaid-joi-D-21-00258.
Among the complications that can occur at dental implants, the fracture of any implant component is a relatively infrequent but clinically relevant problem. Because of their mechanical characteristics, small diameter implants are at higher risk of such complication. The aim of this laboratory and finite element method (FEM) study was to compare the mechanical behavior of a 2.9- and 3.3-mm-diameter implant with a conical connection under standard static and dynamic conditions, following the International Organization for Standardization (ISO) 14801:2017. Finite element analysis was performed to compare the stress distribution on the tested implant systems under a 300-N, 30° inclined force. Static tests were performed with a load cell of 2 kN; the force was applied on the experimental samples at 30° with respect to the implant-abutment axis, with an arm of 5.5 mm. Fatigue tests were performed with decreasing loads, at 2-Hz frequency, until 3 specimens survived without any damage after 2 million cycles. The emergence profile of the abutment resulted the most stressed area in finite element analysis, with a maximum stress of 5829 and 5480 MPa for 2.9- and 3.3-mm-diameter implant complex, respectively. The mean maximum load resulted in 360 N for 2.9-mm-diameter and 370 N for 3.3-mm-diameter implants. The fatigue limit was recorded to be 220 and 240 N, respectively. Despite the more favorable results of 3.3-mm-diameter implants, the difference between the tested implants could be considered clinically negligible. This is probably due to the conical design of the implant-abutment connection, which has been reported to present low stress values in the implant neck region, thus increasing the fracture resistance.
在牙科种植体可能出现的并发症中，任何种植体部件的断裂都是一种相对罕见但具有临床相关性的问题。由于其机械特性，小直径种植体更容易出现这种并发症。本实验室和有限元法（FEM）研究的目的是比较标准静态和动态条件下具有锥形连接的 2.9 和 3.3 毫米直径种植体的机械行为，遵循国际标准化组织（ISO）14801:2017 标准。有限元分析用于比较在 300N、30°倾斜力作用下测试的种植体系统的应力分布。静态测试使用 2kN 的负载单元进行；将实验样品以相对于种植体-基台轴 30°的角度施加力，臂长为 5.5 毫米。疲劳测试采用递减载荷进行，频率为 2Hz，直到 3 个样品在 200 万次循环后没有任何损坏而幸存下来。在有限元分析中，基台的出现轮廓是最受力的区域，2.9 和 3.3 毫米直径种植体复合体的最大应力分别为 5829 和 5480MPa。平均最大载荷导致 2.9 毫米直径种植体为 360N，3.3 毫米直径种植体为 370N。疲劳极限分别记录为 220 和 240N。尽管 3.3 毫米直径种植体的结果更有利，但测试种植体之间的差异可能被认为在临床可以忽略不计。这可能是由于种植体-基台连接的锥形设计，据报道，这种设计在种植体颈部区域会产生较低的应力值，从而提高了抗断裂能力。
