Evaluation of Optimal Taper of Immediately Loaded Wide-Diameter Implants: A Finite Element Analysis

2013 ◽  
Vol 39 (2) ◽  
pp. 123-132 ◽  
Author(s):  
Momen A. Atieh ◽  
Reza A. Shahmiri
Keyword(s):  
Finite Element ◽  
Cancellous Bone ◽  
Strain Distribution ◽  
Immediate Loading ◽  
Stress Strain ◽  
Wide Diameter ◽  
Mandibular Molar ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Molar Extraction

This study aimed to evaluate the effects of different tapering angles of an immediately loaded wide-diameter implant on the stress/strain distribution in bone and implant after implant insertion in healed or fresh molar extraction sockets. A total of 10 finite element (FE) implant-bone models, including 8.1-mm diameter implant, superstructure, and mandibular molar segment, were created to investigate the biomechanical behavior of different implant taper angles in immediate and delayed placement conditions. The degrees of implant taper ranged from 2° to 14°, and the contact conditions between the immediately loaded implants and bone were set with frictional coefficients (μ) of 0.3 in the healed models and 0.1 in the extracted models. Vertical and lateral loading forces of 189.5 N were applied in all models. Regardless of the degree of implant tapering, immediate loading of wide-diameter implants placed in molar extraction sockets generated higher stress/strain levels than implants placed in healed sockets. In all models, the von Mises stresses and strains at the implant surfaces, cortical bone, and cancellous bone increased with the increasing taper angle of the implant body, except for the buccal cancellous bone in the healed models. The maximum von Mises strains were highly concentrated on the buccal cortical struts in the extracted models and around the implant neck in the healed models. The maximum von Mises stresses on the implant threads were more concentrated in the non-tapered coronal part of the 11° and 14° tapered implants, particularly in the healed models, while the stresses were more evenly dissipated along the implant threads in other models. Under immediate loading conditions, the present study indicates that minimally tapered implants generate the most favorable stress and strain distribution patterns in extracted and healed molar sites.

scholarly journals Reconstruction of Severe Acetabular Bone Defect with 3D Printed Ti6Al4V Augment: A Finite Element Study

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jun Fu ◽  
Ming Ni ◽  
Jiying Chen ◽  
Xiang Li ◽  
Wei Chai ◽  
...  
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Bone Defect ◽  
Cancellous Bone ◽  
Acetabular Bone ◽  
Fea Model ◽  
Acetabular Bone Defect ◽  
3D Printed ◽  
Von Mises ◽  
Von Mises Stresses

Purpose. The purpose of this study was to establish the finite element analysis (FEA) model of acetabular bone defect reconstructed by 3D printed Ti6Al4V augment and TM augment and further to analyze the stress distribution and clinical safety of augments, screws, and bones.Methods. The FEA model of acetabular bone defect reconstructed by 3D printed Ti6Al4V augment was established by the CT data of a patient with Paprosky IIIA defect. The von Mises stresses of augments, screws, and bones were analyzed by a single-legged stance loading applied in 3 increments (500 N, 2000 N, and 3000 N).Results. The peak von Mises stresses under the maximal loading in the 3D printed augments, screws, and cortical bone were less than the yield strength of the corresponding component. However, the peak stress in the bone was greater than the yield strength of cancellous bone under walking or jogging loading. And under the same loading, the peak compressive and shear stresses in bone contact with TM augment were larger than these with 3D printed augment.Conclusions. The FEA results show that all the components will be intact under single-legged standing. However, partial cancellous bone contacted with 3D printed augment and screws will lose efficacy under walking or jogging load. So we recommend that patients can stand under full bearing, but can not walk or jog immediately after surgery.

scholarly journals The sensitivity of contact stresses in the mandibular premolar region to the shape of Zirconia dental implant: A 3D finite element study

2018 ◽  
Vol 24 (2) ◽  
pp. 55-63 ◽  
Author(s):  
Duraisamy Velmurugan ◽  
Masilamany Santha Alphin ◽  
Benedict Jain AR Tony
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Cortical Bone ◽  
Transition Region ◽  
Dental Implant ◽  
Cancellous Bone ◽  
Contact Stresses ◽  
Thread Profile ◽  
Von Mises ◽  
Von Mises Stresses

Abstract Background: Implant thread profile plays a vital role in magnitude and distribution of contact stresses at the implant-bone interface. The main goal of this study was to evaluate the biomechanical effects of four distinct thread profiles of a dental implant in the mandibular premolar region. Methods: The dental implant represented the biocompatible Zirconia material and the bone block was modelled as transversely isotropic and elastic material. Three-dimensional finite element simulations were conducted for four distinct thread profiles of a dental implant at 50%, 75%, and 100% osseointegration. An axial static load of 500 N was applied on the abutment surface to estimate the stresses acting within the bones surrounding the implant. Results: Regions of stress concentration were seen mostly along the mesiodistal direction compared to that in the buccolingual direction. The cortical bone close to the cervical region of the implant and the cortical bone next to the first thread of the implant experienced peak stress concentration. Increasing the degree of osseointegration resulted in increased von-Mises stresses on the implant-cortical transition region, the implant-cancellous transition region, the cortical bone, and the cancellous bone. Conclusion: The results show that the application of distinct thread profiles at different degrees of osseointegration had significant effect on the stresses distribution contours in the surrounding bony structure. Comparing all four thread profiles, a dental implant with V-thread profile induced lower values of von-Mises stresses and shear stresses on the implant-cortical transition region, implant-cancellous transition region, cortical bone, and cancellous bone.

scholarly journals Evaluation of Micromovements and Stresses around Single Wide-Diameter and Double Implants for Replacing Mandibular Molar: A Three-Dimensional FEA

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Shrikar R. Desai ◽  
I. Karthikeyan ◽  
Rika Singh
Keyword(s):  
Stress Reduction ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Implant Design ◽  
Immediate Loading ◽  
3D Fem ◽  
Wide Diameter ◽  
Force Magnitude ◽  
Mandibular Molar ◽  
Von Mises

Purpose. The purpose of this finite element study was to compare stresses, strains, and displacements of double versus single implant, in immediate loading for replacing mandibular molar. Materials and Methods. Two 3D FEM models were made to simulate implant designs. The first model used 6 mm wide-diameter implant to support a single molar crown. The second model used 3.75-3.75 double implant design. Each model was analyzed with a single force magnitude of 70 N in oblique axis in three locations. Results. This FEM study suggested that micromotion can be well controlled by both double implants and 6 mm single wide-diameter implant. The Von Mises stress for double implant had 31%–43% stress reduction compared to the 6 mm implant. Conclusion. Within the limitations of the paper, when the mesiodistal space for artificial tooth is more than 12.5 mm, under immediate loading, the double implant support should be considered.

EFFECT OF ANTERIOR IMPLANT POSITION ON BIOMECHANICAL PERFORMANCE IN THE MAXILLARY ALL-ON-FOUR TREATMENT: A 3-D FINITE ELEMENT ANALYSIS

2021 ◽  
Author(s):  
Taygun SEZER ◽  
Kerem Kilic ◽  
Emir Esim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Bone Tissue ◽  
Cancellous Bone ◽  
Principal Stresses ◽  
Element Analysis ◽  
Central Tooth ◽  
Von Mises ◽  
Von Mises Stresses

In the all-on-four concept, the positions of both posterior and anterior implants can affect stress distribution. The aim of this study was to examine the effect of the position of anterior implants on stress distribution in the implant, the bone around the implant, and prosthetic components in the resorbed maxilla using the all-on-four concept. All-on-four designs were prepared with three different anterior implant positions in a fully edentulous maxilla. Anterior implants were placed axially in the central incisor area in model 1, in the lateral incisors area in model 2, and in the canine area in model 3, forming three groups. The von Mises and principal stresses in the bone tissue and the von Mises stresses in the implant and prosthetic components were evaluated by three-dimensional finite element analysis. There were more stresses on the cortical bone than cancellous bone. The stresses on the bone tissue and implant components were generally concentrated around the posterior implant, whereas the stresses on the prosthetic components were generally concentrated in the anterior region. Changing the anterior implant positions from the central tooth to the canine tooth reduced the stress on the bone around the implant. The highest von Mises stresses occurred in the prosthetic superstructure in all models, whereas the lowest stresses occurred in the cancellous bone. Changing the position of the anterior implants from the central tooth to the canine area in the maxillary all-on-four concept created a favourable stress distribution.

A Finite Element Analysis of the Human Temporomandibular Joint

1994 ◽  
Vol 116 (4) ◽  
pp. 401-407 ◽  
Author(s):  
J. Chen ◽  
Liangfeng Xu
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Reaction Force ◽  
Element Model ◽  
Contact Stresses ◽  
Element Analysis ◽  
Tensile Stresses ◽  
Reaction Forces ◽  
Von Mises ◽  
Von Mises Stresses

A 2-D finite element model of the human temporomandibular joint (TMJ) has been developed to investigate the stresses and reaction forces within the joint during normal sagittal jaw closure. The mechanical parameters analyzed were maximum principal and von Mises stresses in the disk, the contact stresses on the condylar and temporal surfaces, and the condylar reactions. The model bypassed the complexity of estimating muscle forces by using measured joint motion as input. The model was evaluated by several tests. The results demonstrated that the resultant condylar reaction force was directed toward the posterior side of the eminence. The contact stresses along the condylar and temporal surfaces were not evenly distributed. Separations were found at both upper and lower boundaries. High tensile stresses were found at the upper boundaries. High tensile stresses were found at the upper boundary of the middle portion of the disk.

Stress and Strain Distribution in the Upsetting Process

2021 ◽  
pp. 288-301
Author(s):  
Japheth Obiko ◽  
Fredrick Madaraka Mwema
Keyword(s):  
Finite Element ◽  
Strain Distribution ◽  
Metal Flow ◽  
Stress Strain ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Contact Surfaces ◽  
Stress Behaviour ◽  
Stress And Strain Distribution ◽  
Forging Load

Numerical simulation of metal flow behaviour was studied using DeformTM3D software. The simulation process was done on X20 steel taken from the software database at 1073-1273K temperature, 10mm/s die speed, and 67% height reduction. From the simulation results, forging load, damage, and stress/strain distributions were obtained. The results show that the forging load increased with a decrease in temperature or decreased with an increase in temperature. The maximum damage values increased as the temperature increased. The obtained maximum damage values were 0.42 (1073K), 0.43 (1173K), and 0.45 (1273K). The damage distribution was inhomogeneous in the deformed cylinder. The stress/strain distributions were inhomogeneous in the deformed cylinder. The location of the maximum strain was at the centre of the deformed cylinder while the maximum stress occurred at the die-cylinder contact surfaces. The study showed that flow stress behaviour can be predicted using finite element method. This shows the feasibility of applying the finite element analysis to analyse the forging process.

Effect of Varus/Valgus Malalignment on Bone Strains in the Proximal Tibia After TKR: An Explicit Finite Element Study

2006 ◽  
Vol 129 (1) ◽  
pp. 1-11 ◽  
Author(s):  
A. Perillo-Marcone ◽  
M. Taylor
Keyword(s):  
Finite Element ◽  
Cancellous Bone ◽  
Tibial Component ◽  
Strain Distribution ◽  
Stance Phase ◽  
Gait Cycle ◽  
Proximal Tibia ◽  
Patient Specific ◽  
Bone Strain ◽  
Bone Strains

Malalignment is the main cause of tibial component loosening. Implants that migrate rapidly in the first two post-operative years are likely to present aseptic loosening. It has been suggested that cancellous bone stresses can be correlated with tibial component migration. A recent study has shown that patient-specific finite element (FE) models have the power to predict the short-term behavior of tibial trays. The stresses generated within the implanted tibia are dependent on the kinematics of the joint; however, previous studies have ignored the kinematics and only applied static loads. Using explicit FE, it is possible to simultaneously predict the kinematics and stresses during a gait cycle. The aim of this study was to examine the cancellous bone strains during the stance phase of the gait cycle, for varying degrees of varus/valgus eccentric loading using explicit FE. A patient-specific model of a proximal tibia was created from CT scan images, including heterogeneous bone properties. The proximal tibia was implanted with a commercial total knee replacement (TKR) model. The stance phase of gait was simulated and the applied loads and boundary conditions were based on those used for the Stanmore knee simulator. Eccentric loading was simulated. As well as examining the tibial bone strains (minimum and maximum principal strain), the kinematics of the bone-implant construct are also reported. The maximum anterior–posterior displacements and internal–external rotations were produced by the model with 20mm offset. The peak minimum and maximum principal strain values increased as the load was shifted laterally, reaching a maximum magnitude for −20mm offset. This suggests that when in varus, the load transferred to the bone is shifted medially, and as the bone supporting this load is stiffer, the resulting peak bone strains are lower than when the load is shifted laterally (valgus). For this particular patient, the TKR design analyzed produced the highest cancellous bone strains when in valgus. This study has provided an insight in the variations produced in bone strain distribution when the axial load is applied eccentrically. To the authors’ knowledge, this is the first time that the bone strain distribution of a proximal implanted tibia has been examined, also accounting for the kinematics of the tibio–femoral joint as part of the simulation. This approach gives greater insight into the overall performance of TKR.

Vertical tail FEA with a CAD/CAE based multidisciplinary process

2018 ◽  
Vol 90 (4) ◽  
pp. 652-658
Author(s):  
Péter Deák
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Tail Length ◽  
Element Model ◽  
Point Of View ◽  
Content Type ◽  
Nodal Displacements ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Aided Design

Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

A fretting finite element investigation of a plane-strain cylindrical contact of Inconel 617/Incoloy 800H at room and high temperatures

2018 ◽  
Vol 233 (4) ◽  
pp. 553-569 ◽  
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Room Temperature ◽  
Tangential Force ◽  
Alloy 800H ◽  
Incoloy 800H ◽  
Inconel 617 ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Two Bodies

This work presents a finite element study of a 2D plane strain fretting model of a half-cylinder in contact with a flat block under oscillatory tangential loading. The two bodies are deformable and are set to Inconel 617 and Incoloy 800H at room temperature (20 ℃) and 800 ℃. However, because the results are normalized, they can characterize a range of contact scales (micro to macro). Different coefficients of friction are used at the interface. This work finds that the edges of the contacting areas experience large von Mises stresses along with significant residual plastic strains, while pileup could also appear when the coefficients of friction are sufficiently large. In addition, junction growth is investigated, showing that the direction of the growth is in the same direction of the tangential force that the weaker material (Incoloy alloy 800H) experiences. The fretting loop (caused by the tangential force during the fretting motion) for the initial few cycles of loading is generated, and it compares well with the reported experimental results. The different extents of damage at room temperature and 800 ℃ are also compared.

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