scholarly journals Evaluation of Bone–Implant Interface Stress and Strain Using Heterogeneous Mandibular Bone Properties Based on Different Empirical Correlations

2021 ◽  
Author(s):  
Mostafa Omran Hussein ◽  
Mohammed Suliman Alruthea
Keyword(s):  
Finite Element ◽  
Group Iv ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Dental Arch ◽  
Stress And Strain ◽  
Bone Implant ◽  
Bone Properties ◽  
Group I ◽  
Von Mises

Abstract Objective The purpose of this study was to compare methods used for calculating heterogeneous patient-specific bone properties used in finite element analysis (FEA), in the field of implant dentistry, with the method based on homogenous bone properties. Materials and Methods In this study, three-dimensional (3D) computed tomography data of an edentulous patient were processed to create a finite element model, and five identical 3D implant models were created and distributed throughout the dental arch. Based on the calculation methods used for bone material assignment, four groups—groups I to IV—were defined. Groups I to III relied on heterogeneous bone property assignment based on different equations, whereas group IV relied on homogenous bone properties. Finally, 150 N vertical and 60-degree-inclined forces were applied at the top of the implant abutments to calculate the von Mises stress and strain. Results Groups I and II presented the highest stress and strain values, respectively. Based on the implant location, differences were observed between the stress values of group I, II, and III compared with group IV; however, no clear order was noted. Accordingly, variable von Mises stress and strain reactions at the bone–implant interface were observed among the heterogeneous bone property groups when compared with the homogenous property group results at the same implant positions. Conclusion Although the use of heterogeneous bone properties as material assignments in FEA studies seem promising for patient-specific analysis, the variations between their results raise doubts about their reliability. The results were influenced by implants’ locations leading to misleading clinical simulations.

scholarly journals Biomechanical behavior of overdentures supported by different implant position and angulation using Micro ERA® system

2019 ◽  
Vol 18 ◽  
pp. e191667
Author(s):  
Felipe Franco Ferreira ◽  
Guilherme Almeida Borges ◽  
Letícia Del Rio Silva ◽  
Daniele Valente Velôso ◽  
Thaís Barbin ◽  
...  
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Equivalent Stress ◽  
Lateral Incisor ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Bone Implant ◽  
Implant Position ◽  
Biomechanical Behavior ◽  
Von Mises

Aim: The aim of this study was to investigate the biomechanical behavior of implant-retained mandibular overdentures using Micro ERA® system with different implant position and angulation by finite element analysis (FEA). Methods: Four 3D finite element models of simplified mandibular overdentures were constructed, using one Bränemark implant with a Micro ERA® attachment. The implant was positioned on the canine or lateral incisor area with an angulation of either 0º (C-0º; LI-0º) or 17º (C-17º, LI-17º) to the vertical axis. A 100 N axial load was applied in one side simultaneously, from first premolar to second molar. In all models it was analyzed the overdenture displacement, compressive/tensile stress in the bone-implant interface, and also the von Mises equivalent stress for the nylon component of the housing. The stresses were obtained (numerically and color-coded) for further comparison among all the groups. Results: The displacement on the overdenture was higher at the posterior surface for all groups, especially in the C-17º group. When comparing the compressive/tensile stress in the bone-implant interface, the lateral-incisor groups (LI-0º and LI-17º) had the highest compressive and lowest tensile stress compared to the canine groups (C-0º and C-17º). The von Mises stress on the nylon component generated higher stress value for the LI-0º among all groups. Conclusions: The inclination and positioning of the implant in mandibular overdenture interferes directly in the stress distribution. The results showed that angulated implants had the highest displacement. While the implants placed in the lateral incisor position presented lower compressive and higher tensile stress respectively. For the attachment the canine groups had the lowest stress.

scholarly journals Evaluation of the Effect of Complete and Partial Osseointegration in Stress Development at Bone-Implant Interface: A 3D Finite Element Study

2016 ◽  
Vol 6 (2) ◽  
pp. 24-27
Author(s):  
Bashu Raj Pandey ◽  
Hemant Kumar Halwai ◽  
Khushbu Adhikari ◽  
Amresh Thakur
Keyword(s):  
Finite Element ◽  
Cortical Bone ◽  
Cancellous Bone ◽  
Element Model ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Bone Implant ◽  
Stress Development ◽  
Bone Segment ◽  
Von Mises

Introduction: Mini-implant has been in use as temporary anchorage device in orthodontics. Various factors like length, type of osseointegration, magnitude and direction of force, insertion angle of the mini-implant affect the stress development at the bone and implant interface. Development of undesirable stress at the bone-implant interface can lead to bone defect and failure of the implant. Various opinions regarding the need of osseointegration have been reported.Objective: To study the effect of complete and partial osseointegration on Von Mises stress distribution at the bone-implant interface.Materials & Method: Finite element model of 9mm × 1.5mm mini-implant and bone segment of 1.5mm were constructed to simulate the biomechanical response of the bone to the mini- implant by using CATIA V5-6R 2013 software. Stress developed on implant and bone were analyzed by using ANSYS: 13 2013 version software for both complete and partial level of osseointegration.Result: Maximum Von Mises stress in complete osseointegration was 14.49 Mpa in cortical bone, 0.551 Mpa in cancellous bone and 50.76 Mpa in implant. In partial osseointegration, it was 18.68 Mpa in cortical bone, 1.23 Mpa in cancellous bone and 66.80 Mpa in mini-implant.Conclusion: In partial osseointegration, stress developed was higher but well below the yield strength of respected continuum. So the partial osseointegration is a good compromise between the necessity of reducing mobility of implant and the necessity for easier screw removal. Key words: cancellous bone, cortical bone, Finite element analysis, mini-implant, Von Mises stress

On the Effect of Screw Preload on the Stress Distribution of Mandibles During Segmental Defect Treatment Using an Additively Manufactured Hardware

2016 ◽  
Author(s):  
Amirhesam Amerinatanzi ◽  
Narges Shayesteh Moghaddam ◽  
Ahmadreza Jahadakbar ◽  
David Dean ◽  
Mohammad Elahinia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Fixation Device ◽  
Element Analysis ◽  
Porous Niti ◽  
The Finite Element Analysis ◽  
Low Stiffness ◽  
Von Mises

The most common method for mandibular reconstructive surgery is the use of a Ti-6Al-4V fixation device and a fibular double barrel graft. This highly stiff fixation hardware (E = 112 GPa) often shields the bone graft (E = 20 GPa) from carrying the load, which may result in bone resorption. Highly stiff Ti-6Al-4V fixation hardware is also likely to concentrate stress in the fixation plate or at screw threads, possibly leading to hardware cracking or screw pull-out. As a solution for that, we have proposed and studied the effect of using a low stiffness, porous NiTi fixation device [1–4]. Although the stress in the fixation device is increased, using such low stiffness fixation hardware, is preferable to have an even higher stress on the graft in order to minimize the risk of resorption or hardware failure. We assume that preloading screws allows them to better engage the fixation hardware with the plate and the surrounding bone and causes an increased von Mises stress. The fixation device can be patient-specific and additively manufactured, such that the shape would match the outer surface of the cortical bone. In this study, we modeled a healthy cadaver mandible via CT-derived 3D surface data. The mandible was virtually resected in the molar region (M1−3). The model simulated the result of reconstructive surgery under the highest chewing loading regime (i.e., 526 N on first right molar tooth [5, 6]) where reconstruction was done with either Ti-6Al-4V fixation hardware or patient specific, stiffness-matched, porous NiTi fixation hardware. The calibration of the material properties for this simulation was done using experimentally obtained data (DSC and compression tests) of Ni-rich NiTi bulk samples. The analyzed term in the finite element analysis was stress distribution in the cortical and cancellous bone. Porous NiTi fixation devices were also produced using Selective Laser Melting (SLM) using the geometry of the aforementioned cadaver mandible. In this paper we have studied the effect of additional torque or preload on the performance of the fixation plates. The finite element analysis demonstrated that applying a preload to the screws increased the stress on the bone. Under similar levels of applied preload, the porous NiTi fixation device showed an increased level of von Mises stress in the bone, particularly in the graft. Additionally, the analysis indicated the higher level of stress on the bone surrounding the screws for the case of using NiTi, which could contribute to increasing screw stability. The fabricated patient-specific fixation hardware not only matched the shape of cortical bone but also contained the level of porosity that defines the appropriate modulus of elasticity.

scholarly journals A deep learning approach to estimate stress distribution: a fast and accurate surrogate of finite-element analysis

2018 ◽  
Vol 15 (138) ◽  
pp. 20170844 ◽  
Author(s):  
Liang Liang ◽  
Minliang Liu ◽  
Caitlin Martin ◽  
Wei Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deep Learning ◽  
Stress Distribution ◽  
Machine Learning Techniques ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Stress Distributions ◽  
Element Analysis ◽  
Von Mises

Structural finite-element analysis (FEA) has been widely used to study the biomechanics of human tissues and organs, as well as tissue–medical device interactions, and treatment strategies. However, patient-specific FEA models usually require complex procedures to set up and long computing times to obtain final simulation results, preventing prompt feedback to clinicians in time-sensitive clinical applications. In this study, by using machine learning techniques, we developed a deep learning (DL) model to directly estimate the stress distributions of the aorta. The DL model was designed and trained to take the input of FEA and directly output the aortic wall stress distributions, bypassing the FEA calculation process. The trained DL model is capable of predicting the stress distributions with average errors of 0.492% and 0.891% in the Von Mises stress distribution and peak Von Mises stress, respectively. This study marks, to our knowledge, the first study that demonstrates the feasibility and great potential of using the DL technique as a fast and accurate surrogate of FEA for stress analysis.

scholarly journals Finite Element Analysis of Orthodontic Relapse in Different Maxillary Arch Form

2021 ◽  
Author(s):  
Yuanyuan Li, MD ◽  
Yiting Shao, MD ◽  
Yansong Yu, MD ◽  
Yushan Ye, MD ◽  
Yingjuan Lu, PhD ◽  
...  
Keyword(s):  
Finite Element ◽  
Von Mises Stress ◽  
Dental Arch ◽  
Finite Element Models ◽  
Element Analysis ◽  
3D Finite Element ◽  
Arch Form ◽  
Arch Forms ◽  
Von Mises ◽  
Maxillary Arch

Background: Orthodontic relapse is fairly common; however, the mechanisms between relapse and the dental arch form remain unclear. The purpose of our study was to establish three-dimensional (3D) finite element models of different dental arch forms after orthodontic treatment and to analyze the states of different arches applied with various sagittal forces.Methods: By calculating the equations of different dental arch forms and combining them with a full maxillary arch (14 teeth), 3D finite element models of square, oval, and tapered dental arches were established; they were designed to be subjected to anterior lingual, posterior mesial, and combined forces, respectively.Results: The von Mises stress and displacement of teeth under different forces were calculated for each loading scenario. Under the different forcing scenarios, all incisors had irregularity trends, and the inclination and intrusion of the canines were increased, and the premolars had a tendency to buccal or lingual crown tipping or even intrusion in our study. The tapered arch was the most stable and had the smallest displacement and von Mises stress, followed by the ovoid arch; the most unstable arch was the square arch.Conclusions: To achieve a stable orthodontic effect, a tapered or ovoid arch, rather than a square arch, should be chosen as the final outcome of treatment.

scholarly journals Patient-specific finite element analysis of frictional behavior in different esophageal regions during endoscopy

2020 ◽  
Vol 22 (2) ◽  
Author(s):  
Chengxiong Lin ◽  
Pan Ren ◽  
Wei Li ◽  
Hengyi Deng ◽  
Zhongrong Zhou
Keyword(s):  
Finite Element ◽  
Von Mises Stress ◽  
Dominant Factor ◽  
Patient Specific ◽  
Thoracic Region ◽  
Specific Patient ◽  
Frictional Behavior ◽  
Narrow Region ◽  
Abdominal Region ◽  
Von Mises

Purpose: Endoscopy is a common and effective method to treat digestive system diseases. Not only can it detect the physiological state of the digestive tract, but also can conduct clinical operations. As a result, it’s of great significance to make clear the relationship between the clinical operation and the complications. Methods: Considering the difficulty in measuring the contact force and determining the stress distribution in real time during endoscopy, a specific-patient finite element model for the frictional behavior at the endoscope-esophagus interface was built in current study. By collecting the CT data of the patient, a 3D esophagus model was built and divided into three characteristic regions (narrow region, thoracic region and abdominal region) according to the physiological structure. Results: Results showed that the radius of the narrowest position was the dominant factor for the maximum von Mises stress when the endoscope passed through the narrow region. For abdominal region and thoracic region, with the increasing coefficient of friction (COF) and amplitude, the total force duo to frictional force (CFSM), frictional dissipation (FD), strain energy (SE) and maximum von Mises stress (Max) all increased correspondingly. Meanwhile, the region of stress concentration gradually approached the initial contact stage. Conclusions: The results can provide theoretical basis and technical support for clinical application and offer some suggestions for medical workers during endoscopy as well.

scholarly journals Finite Element Analysis of Stress in Bone and Abutment-Implant Interface under Static and Cyclic Loadings

2020 ◽  
Author(s):  
Saeed Nokar ◽  
Hamid Jalali ◽  
Farideh Nozari ◽  
Mahnaz Arshad
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Maximum Stress ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Bone Implant ◽  
Factors Affecting ◽  
Von Mises

Objectives: The success of implant treatment depends on many factors affecting the bone-implant, implant-abutment, and abutment-prosthesis interfaces. Stress distribution in bone plays a major role in success/failure of dental implants. This study aimed to assess the pattern of stress distribution in bone and abutment-implant interface under static and cyclic loadings using finite element analysis (FEA). Materials and Methods: In this study, ITI implants (4.1×12 mm) placed at the second premolar site with Synocta abutments and metal-ceramic crowns were simulated using SolidWorks 2007 and ABAQUS software. The bone-implant contact was assumed to be 100%. The abutments were tightened with 35 Ncm preload torque according to the manufacturer’s instructions. Static and cyclic loads were applied in axial (116 Ncm), lingual (18 Ncm), and mesiodistal (24 Ncm) directions. The maximum von Mises stress and strain values ​​were recorded. Results: The maximum stress concentration was at the abutment neck during both static and cyclic loadings. Also, maximum stress concentration was observed in the cortical bone. The loading stress was higher in cyclic than static loading. Conclusion: Within the limitations of this study, it can be concluded that the level of stress in single-unit implant restorations is within the tolerable range by bone.

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

The Influence of Loading Position in A Priori High Stress Detection using Mode Superposition

2020 ◽  
Vol 1 (1) ◽  
pp. 93-102
Author(s):  
Carsten Strzalka ◽  
◽  
Manfred Zehn ◽  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
A Priori ◽  
High Stress ◽  
Von Mises Stress ◽  
Detailed Knowledge ◽  
Variable Loading ◽  
Numerical Effort ◽  
Von Mises

For the analysis of structural components, the finite element method (FEM) has become the most widely applied tool for numerical stress- and subsequent durability analyses. In industrial application advanced FE-models result in high numbers of degrees of freedom, making dynamic analyses time-consuming and expensive. As detailed finite element models are necessary for accurate stress results, the resulting data and connected numerical effort from dynamic stress analysis can be high. For the reduction of that effort, sophisticated methods have been developed to limit numerical calculations and processing of data to only small fractions of the global model. Therefore, detailed knowledge of the position of a component’s highly stressed areas is of great advantage for any present or subsequent analysis steps. In this paper an efficient method for the a priori detection of highly stressed areas of force-excited components is presented, based on modal stress superposition. As the component’s dynamic response and corresponding stress is always a function of its excitation, special attention is paid to the influence of the loading position. Based on the frequency domain solution of the modally decoupled equations of motion, a coefficient for a priori weighted superposition of modal von Mises stress fields is developed and validated on a simply supported cantilever beam structure with variable loading positions. The proposed approach is then applied to a simplified industrial model of a twist beam rear axle.

scholarly journals Finite Element Analysis of Composite Repair for Damaged Steel Pipeline

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 301
Author(s):  
Jiaqi Chen ◽  
Hao Wang ◽  
Milad Salemi ◽  
Perumalsamy N. Balaguru
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Hoop Stress ◽  
Pipe Wall ◽  
Von Mises Stress ◽  
Repair System ◽  
Composite Repair ◽  
Steel Pipeline ◽  
Von Mises ◽  
Infill Material

Carbon fiber reinforced polymer (CFRP) matrix composite overwrap repair systems have been introduced and accepted as an alternative repair system for steel pipeline. This paper aimed to evaluate the mechanical behavior of damaged steel pipeline with CFRP repair using finite element (FE) analysis. Two different repair strategies, namely wrap repair and patch repair, were considered. The mechanical responses of pipeline with the composite repair system under the maximum allowable operating pressure (MAOP) was analyzed using the validated FE models. The design parameters of the CFRP repair system were analyzed, including patch/wrap size and thickness, defect size, interface bonding, and the material properties of the infill material. The results show that both the stress in the pipe wall and CFRP could be reduced by using a thicker CFRP. With the increase in patch size in the hoop direction, the maximum von Mises stress in the pipe wall generally decreased as the maximum hoop stress in the CFRP increased. The reinforcement of the CFRP repair system could be enhanced by using infill material with a higher elastic modulus. The CFRP patch tended to cause higher interface shear stress than CFRP wrap, but the shear stress could be reduced by using a thicker CFRP. Compared with the fully bonded condition, the frictional interface causes a decrease in hoop stress in the CFRP but an increase in von Mises stress in the steel. The study results indicate the feasibility of composite repair for damaged steel pipeline.

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