目的:研究采用三维(3D)有限元分析(FEA),并检查了植入物直径如何影响整个植入物-骨接触的应力分布,以及在轴向和非轴向载荷过程中通过该界面的应力传递如何变化。
方法:使用患者的锥形束CT创建了3D下颌模型,该患者的植入物插入了第一下颌磨牙。NobelBiocare植入物(NobelBiocare,瑞士),具体尺寸为3.5毫米,4.3mm,5.0mm,选择6.0毫米。模型是在CATIAV5R19(达索系统,法国)从螺纹钛植入物尺寸。利用ANSYSWorkbenchv11.0对植入物进行有限元建模(Ansys、Inc,宾夕法尼亚,美国)。分析涉及应用100N轴向,50N颊舌,和50N的远端负荷。
结果:在下第一磨牙骨段,植入物顶面以100N轴向加载,50N颊舌,和50N的近端方向。植入物颈部近端皮质骨的vonMises应力最大,无论模型或压力情景如何。在I型皮质骨,最大应力集中在植入物颈部。大部分应力在舌骨板上,口腔较小,至少在中端和远端。不到一半的植入物应力传递到皮质骨。在模型II中,从植入物转移到皮质骨的应力小于植入物应力的一半。模型III和模型IV也是如此。在I型松质骨中,应力集中在植入物的冠状半部,而在顶端半部最小。
结论:轴向载荷下的应力分布良好。因此,可以推断,植入物的直径的增大通过提供用于应力分散的更大的表面积来增强骨与植入物之间的界面处的应力的均匀分布。此外,据确定,沿植入物的轴施加力是一个有益的加载方向,不会对其寿命产生负面影响。
OBJECTIVE: The study employed three-dimensional (3D) finite element analysis (FEA) and examined how implant diameters affect stress distribution across the implant-bone contact and how stress transmission through this interface changes during axial and non-axial loading.
METHODS: A 3D mandibular model was created using cone beam CT of a patient with implants inserted into the first mandible molar. Nobel Biocare implants (Nobel Biocare, Switzerland) with specific dimensions of 3.5 mm, 4.3 mm, 5.0 mm, and 6.0 mm were chosen. Models were created in CATIAV5R19 (Dassault Systemes, France) from threaded titanium implant dimensions. Implants were finite element-modeled utilizing ANSYS Workbench v11.0 (Ansys, Inc, Pennsylvania, USA). The analysis involved applying 100 N axial, 50 N buccolingual, and 50 N mesiodistal loads.
RESULTS: In a lower first molar bone segment, the implant top surface was loaded in 100 N axial, 50 N buccolingual, and 50 N mesiodistal orientations. The cortical bone proximal to the implant neck had the most von Mises stress, regardless of model or stress scenario. In Model I cortical bone, maximal stress was centered at the implant neck. Most stress was on lingual bone plates, lesser on buccal, and least on mesial and distal. Less than half of the implant stress was transmitted to the cortical bone. The stress transferred from the implant to the cortical bone in Model II was less than half of the implant stress. The same was true for Models III and IV. In Model I cancellous bone, stress was concentrated in the implant\'s coronal half and minimal in the apical half.
CONCLUSIONS: The stress patterns under axial loading were distributed favorably. Therefore, it can be inferred that an augmentation in the diameter of the implant enhances the even distribution of stress at the interface between the bone and the implant by offering a larger surface area for the dispersion of stress. Furthermore, it was determined that applying force along an implant\'s axis was a beneficial loading direction and did not negatively impact its lifespan.