Evaluation of Fatigue Life for Dental Implants Using FEM Analysis

Abstract

The purpose of this study is to numerically analyze a 3D model of an implant under fatigue loads. A bone and a V shape implant were modeled using SolidWorks2008 software. In order to obtain an exact model, the bone was assumed as a linear orthotropic material. Mechanical loads were applied in terms of fastening torque to the abutment and mastication force applied at the top of the crown. The abutment was tightened into the implant by applying a 35 N.cm torque causing tensile stress within the abutment screw as a preload that is harmful not only for the fatigue life of the abutment, but also for the stability of the implant-abutment interface. A 700 N force at an angle of 30 degrees to the vertical direction was applied to the crown. The mechanical analysis results showed that the abutment is the critical component of the implant system in terms of fatigue failure. This is due to the fact that the tensile preloads originated from the fastening torque. The results were presented in terms of fatigue life in the abutment. Fatigue life of the abutment and implant were calculated based on the Goodman, Soderberg, Smith–Watson–Topper (SWT), and Marrow theories. According to the results of the fatigue life prediction, abutment screws may fail after about 3 × 105 cycles. The predicted results by the Goodman theory are at a very good accordance with the clinical data.

Stress-strain and fatigue life numerical evaluation of two different dental implants considering isotropic and anisotropic human jaw

“…Although they are restricted area, they result very dangerous because they may spread out toxic titanium ions in the neighbor tissues, causing inflammations 73 or severe biological reactions such as cell necrosis. 74 Actually the fixing screw (Figure 7(a)) was not the only critical structure, but also the abutmentimplant interface, 14 when the Load 3 is applied, as underlined just below (Figure 7(b)). This happens even when the anisotropy effect is adopted, reducing the lifetime from about 360 cycles to 127 cycles.…”

“…Consequently, in order to avoid this undesired occurrence, several studies have been conducted in the last years, with the aim of investigating and analyzing the fatigue behavior of dental implants. Ziaie and Khalili, 14 by using a Finite Element Analysis (FEA), noted that the abutment may be a critical component of the total assembly. In addition, they found that the root of the implant body screw, in proximity of the bone level, had the greatest probability of failure.…”

Three-Dimensional Finite Element Investigation into Effects of Implant Thread Design and Loading Rate on Stress Distribution in Dental Implants and Anisotropic Bone

“…As a result, the induced stress does not usually exceed the yield strength of the dental implant material (e.g., 550 MPa for titanium, [44]) or bone (190 MPa for cortical bone, and 10 MPa for cancellous bone [44]). Therefore, in comparison to more realistic cyclic loading, static loads are associated with a less critical effect, creating less stress in the dental implant system [45]. Similarly, quasi-static loading has no significant influence on both implant and surrounding bone.…”

Fatigue life estimation of dental implants using a combination of the finite element method and traditional fatigue criteria

“…Despite its popularity, only a few studies used finite element (FE) models to evaluate fatigue on dental prostheses. 6,15,37 Kayabas xi et al 6 evaluated the life in fatigue of dental implants using traditional methods and FE models. In that study, stress levels from the implant were directly extracted from the model and evaluated in the fatigue criteria but without accounting for the external factors that can affect the life of a component, 17 such as implant shape and loading conditions.…”