GEOMETRICAL OPTIMIZATION OF DENTAL IMPLANTS WITH REGARD TO OSSEOINTEGRATION

A newly developed reference dental implant specimen type was subjected to numerical simulations of osseointegration. The goal of these tests was to optimize the geometry of the implant so as to reduce local stress concentrations and provide a better flow of stress through the whole implant body. Conditions for osseointegration were considered when evaluating the anchoring system of the implant in regard to its placement in the human cancellous and cortical bone. Numerical simulations showed that stress concentrations occur mostly in the upper cylindrical part of the implant. By increasing the width of this cylindrical part, we were able to reduce the maximum values of von-Mises stress by 20 %.

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Altered Load Transfer in the Pelvis in the Presence of Periprosthetic Osteolysis

Journal of Biomechanical Engineering ◽

10.1115/1.4028522 ◽

2014 ◽

Vol 136 (11) ◽

Cited By ~ 1

Author(s):

Jacob T. Munro ◽

Justin W. Fernandez ◽

James S. Millar ◽

Cameron G. Walker ◽

Donald W. Howie ◽

...

Keyword(s):

Cortical Bone ◽

Load Transfer ◽

Von Mises Stress ◽

Patient Specific ◽

Fe Model ◽

Stress Concentrations ◽

Periprosthetic Osteolysis ◽

Total Hip ◽

Long Term Follow Up ◽

Von Mises

Periprosthetic osteolysis in the retroacetabular region with cancellous bone loss is a recognized phenomenon in the long-term follow-up of total hip replacement. The effects on load transfer in the presence of defects are less well known. A validated, patient-specific, 3D finite element (FE) model of the pelvis was used to assess changes in load transfer associated with periprosthetic osteolysis adjacent to a cementless total hip arthroplasty (THA) component. The presence of a cancellous defect significantly increased (p < 0.05) von Mises stress in the cortical bone of the pelvis during walking and a fall onto the side. At loads consistent with single leg stance, this was still less than the predicted yield stress for cortical bone. During higher loads associated with a fall onto the side, highest stress concentrations occurred in the superior and inferior pubic rami and in the anterior column of the acetabulum with larger cancellous defects.

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A SIMPLE AND EFFICIENT METHODOLOGY TO IMPROVE DESIGN PROPOSALS OF DENTAL IMPLANTS — A DESIGN CASE STUDY

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237215500374 ◽

2015 ◽

Vol 27 (04) ◽

pp. 1550037 ◽

Cited By ~ 1

Author(s):

G. Uzcátegui ◽

E. Dávila ◽

M. Cerrolaza

Keyword(s):

Dental Implants ◽

Dental Implant ◽

Geometric Characteristic ◽

Von Mises Stress ◽

Implant Design ◽

Improve Design ◽

Final Design ◽

Improved Performance ◽

Von Mises ◽

Iso 14801

Objective: To propose a methodology based on virtual simulation to assist in the design proposals of dental implants. Methods: The finite element method (FEM) was used to analyze the biomechanical dental implant system behavior, determining von Mises stress distribution induced by functional loads, varying parameter as load direction and geometric characteristic of the implant (taper, length, abutment angulation, thread pitch and width pitch). A final design was obtained by considering the parameters that showed improved performance. The estimated lifetime of the final design was calculated by reproducing in a virtual way the experimental fatigue test required by the ISO:14801 standards. Results: For all the studied cases, the maximum stresses were obtained in the connecting screw under oblique loads (OLs). The estimated lifetime for this critical part is at least 5 × 106 cycles, which meets the requirement of the ISO:14801. In bone tissue, the largest stresses were concentrated in cortical bone, in the zone surrounding the implant, in good agreement with previous reports. Conclusions: A dental implant design was obtained and validated through a simple and efficient methodology based on the application of numerical methods and computer simulations.

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A suggested design for a tissue level dental implant

Asian Journal of Oral Health and Allied Sciences ◽

10.25259/ajohas_5_2021 ◽

2021 ◽

Vol 11 ◽

pp. 3

Author(s):

Faaiz Y. Alhamdani ◽

Basma A. Al-Ghali

Keyword(s):

Cortical Bone ◽

Dental Implant ◽

Pure Titanium ◽

Tissue Level ◽

Von Mises Stress ◽

Dental Arch ◽

Commercially Pure Titanium ◽

Element Analysis ◽

Von Mises ◽

Surrounding Bone

Objectives: The aim of the study was to test the stress distribution around a newly suggested design for tissue-level dental implant. Material and Methods: Newly designed modified reverse buttress thread dental implant is tested for the stress over the surrounding bone. Nine implant dimensions of this design were examined on two types of materials; commercially pure Titanium (TiG4) and Titanium alloy (TIG5). These nine implant dimensions, which can be used in the full dental arch are: (diameter/length; 3.5/11, 4/11, 4/9, 4.5/11, 4.5/9, 5/11, 5/9, 5/7, and 5.5/7 mm). The suggested implant was designed using Autodesk Inventor 202. ANSYS Workbench 2020 R2 was used for meshing and 3D finite element analysis. Results: Maximum Von Mises stress over the cortical bone is higher in the TiG5 model in all implant dimensions. The highest stress value was reported in the implant 4/9 mm dimension in both models. TiG5 model has the highest stress values over the cancellous bone. The higher level of stress over the surrounding cortical bone lies at the surface of the cortical bone, whereas the maximum stress over the surrounding trabecular bone was noticed near the tip of the first and second dental implant thread. Conclusion: Reasonable levels of stress were reported in the suggested design in both models. However, it would be justifiable to choose the TiG4 model for the suggested tissue level implant with the exclusion of a 4/9 mm dimension to ensure minimal stress over the surrounding cortical bone.

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Effect of material and dimensions on the mechanical behavior of a dental implant

Materials Testing ◽

10.1515/mt-2020-620804 ◽

2020 ◽

Vol 62 (8) ◽

pp. 775-782

Author(s):

S. Hedia Hassan ◽

Ismail M. R. Najjar ◽

Noha Fouda ◽

Fisal W. Al-Thobiani ◽

Hattan A. Timraz

Keyword(s):

Stainless Steel ◽

Dental Implants ◽

Dental Implant ◽

Large Diameter ◽

Stress Shielding ◽

Von Mises Stress ◽

Shielding Effect ◽

Element Analysis ◽

Maximum Increase ◽

Von Mises

Abstract Metallic dental implants such as titanium and stainless steel have an elastic modulus 5-14 times greater than that of compact bone (15 GPa). These stiff implants do not adequately strain the bone, which can result in bone resorption through a phenomenon referred to as stress shielding. The implant length and diameter has a significant influence on the stress distribution within the surrounding jawbone. Therefore, the objective of this investigation is to optimize the material and the dimensions of a dental implant. A numerical solution of a 3D finite element analysis using ANSYS software was conducted to achieve this purpose. It was concluded that by using stainless steel, titanium or gold dental implants with a large diameter and short length the values of the maximum von Mises stress values in cortical bone were increased. The maximum increase in von Mises stress can be obtained by using a stainless steel implant. This dental implant will reduce the stress shielding effect as well as yield suitable values with respect to von Mises stress for both porcelain crowns and dental implants, thus increasing the service life of the implant.

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A comparative finite element analysis of two types of axial and radial functionally graded dental implants with titanium one around implant-bone interface

Science and Engineering of Composite Materials ◽

10.1515/secm-2015-0392 ◽

2017 ◽

Vol 24 (5) ◽

pp. 747-754 ◽

Cited By ~ 3

Author(s):

Hadi Asgharzadeh Shirazi ◽

Majidreza Ayatollahi ◽

Alireza Karimi ◽

Mahdi Navidbakhsh

Keyword(s):

Finite Element ◽

Dental Implants ◽

Dental Implant ◽

Functionally Graded ◽

Von Mises Stress ◽

Element Analysis ◽

Bone Interface ◽

The Common ◽

Von Mises ◽

Implant System

AbstractFunctionally graded biomaterials (FGBMs) have received significant attention in the recent years as potential candidates for the next generation of dental implant improvement. This happened due to their unique advantages and their ability to satisfy the requirements of both biomechanical and biocompatibility properties simultaneously. This study was aimed to analyze the effects of two radial and axial FGBM dental implants on the stress distribution near the dental implant-bone interface under a static load using finite element method (FEM). The model was restrained on a base supporting bone and vertically loaded with a force of 100 N on the top of the abutment. In the FGBM models, the implants are made of a combination of bioceramic and biometal composition, with properties that change gradually and continuously in the radial and axial directions. The numerical results indicated that the use of both radial and axial FGBM dental implants reduced the maximum von Mises stress in the cortical and the cancellous bones in comparison with the common titanium one, which leads to faster bone regeneration and early stabilization of dental implant system. The findings of the present study may have implications not only for understanding the stresses and deformations around the implant-bone interface but also for improving the performance as well as application of FGBMs in dental implant materials.

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Is Perpendicular Double Two-Hole Plates Fixation Superior to Single Four-Hole Plate Fixation to Treat Mandibular Symphysis Fracture?—A Finite Element Study

Applied Sciences ◽

10.3390/app11188629 ◽

2021 ◽

Vol 11 (18) ◽

pp. 8629

Author(s):

Li-Ren Chang ◽

Ya-Pei Hou ◽

Ting-Sheng Lin

Keyword(s):

Finite Element ◽

Plate Fixation ◽

Mandibular Condyle ◽

Fracture Site ◽

Von Mises Stress ◽

Stress Concentrations ◽

Element Analysis ◽

Mandibular Symphysis ◽

Lower Border ◽

Von Mises

The effectiveness of a single four-hole plate (S4HP), perpendicularly oriented four-hole and two-hole plate (Per4H2HP), and perpendicularly oriented double two-hole plate (PerD2HP) for the fixation of a mandibular fracture was studied. A finite element analysis of the mandibular symphysis fractures treated with S4HP, Per4H2HP, and PerD2HP was performed. All surface nodes were fixed in the mandibular condyle region and occlusal muscle forces were applied. The maximal von Mises stress (MaxVMS) values of the plates, screws and screw holes were investigated. The displacement of the fracture site on the lower border of the mandibular symphysis was recorded. The displacement on the lower border of the fracture sites in the S4HP group was greater than that in the Per4H2HP group and the PerD2HP group. There was no eversion at the fracture site among all groups. Both the S4HP and Per4H2HP groups showed stress concentrations on the screws close to the fracture site. The MaxVMS increased when the number of screw holes on the mandibular anterior lower border decreased. The displacement of the fracture site and eversion with Per4H2HP and PerD2HP were far lower than those with S4HP. PerD2HP is a stable and green fixation technique for mandibular symphysis fractures.

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Effects of placement angle and direction of orthopedic force application on the stability of orthodontic miniscrews

The Angle Orthodontist ◽

10.2319/090112-703.1 ◽

2012 ◽

Vol 83 (4) ◽

pp. 667-673 ◽

Cited By ~ 16

Author(s):

Jihye Lee ◽

Ji Young Kim ◽

Yoon Jeong Choi ◽

Kyung-Ho Kim ◽

Chooryung J. Chung

Keyword(s):

Cortical Bone ◽

Lateral Force ◽

Von Mises Stress ◽

Biomechanical Stability ◽

Element Analysis ◽

Force Application ◽

Pull Out ◽

The Stability ◽

Von Mises ◽

Pull Out Strength

ABSTRACT Objectives: To evaluate the influence of placement angle and direction of orthopedic force application on the stability of miniscrews. Materials and Methods: Finite element analysis was performed using miniscrews inserted into supporting bone at angles of 90°, 60°, and 30° (P90°, P60°, and P30°). An orthopedic heavy force of 800 gf was applied to the heads of the miniscrews in four upward (U0°, U30°, U60°, U90°) or lateral (L0°, L30°, L60°, L90°) directions. In addition, pull-out strength of the miniscrews was measured with various force directions and cortical bone thicknesses. Results: Miniscrews with a placement angle of 30° (P30°) and 60° (P60°) showed a significant increase in maximum von Mises stress following the increase in lateral force vectors (U30°, U60°, U90°) compared to those with a placement angle of 90° (P90°). In accordance, the pull-out strength was higher with the axial upward force when compared to the upward force with lateral vectors. Maximum von Mises stress and displacement of the miniscrew increased as the angle of lateral force increased (L30°, L60°, L90°). However, a more dramatic increase in maximum von Mises stress was noted in P30° than in P60° and P90°. Conclusion: Placement of the miniscrew perpendicular to the cortical bone is advantageous in terms of biomechanical stability. Placement angles of less than 60° can reduce the stability of miniscrews when orthopedic forces are applied in various directions.

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Effect of Fiber Posts on Stress Distribution of Endodontically Treated Upper Premolars: Finite Element Analysis

Nanomaterials ◽

10.3390/nano10091708 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1708 ◽

Cited By ~ 1

Author(s):

Maciej Zarow ◽

Mirco Vadini ◽

Agnieszka Chojnacka-Brozek ◽

Katarzyna Szczeklik ◽

Grzegorz Milewski ◽

...

Keyword(s):

Finite Element ◽

Stress Distribution ◽

Resin Composite ◽

Von Mises Stress ◽

Stress Distributions ◽

Stress Concentrations ◽

Element Analysis ◽

Endodontically Treated Tooth ◽

Maxillary Premolars ◽

Von Mises

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial–occlusal–distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal–palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin.

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Finite Element Simulation of Tensile Behaviors in the Elastic Region for PP/Nano-TiO2 Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.150-151.1819 ◽

2010 ◽

Vol 150-151 ◽

pp. 1819-1823

Author(s):

Yu Jiao Wu ◽

Ming Rui Gao ◽

Yu Ling Chen ◽

Juan Li ◽

Shao Lin Ju

Keyword(s):

Finite Element ◽

Stress Field ◽

Volume Fraction ◽

Local Stress ◽

Von Mises Stress ◽

Analysis Model ◽

Nano Tio2 ◽

Two Phase ◽

Element Analysis ◽

Von Mises

Polypropylene(PP)/nano-TiO2 composites were prepared by the melt intercalation molding. Based on the assumption of continuum mechanics model for materials, a finite element analysis model for the composites was constructed using ANSYS 11.0 software. In the stage of deformation (pre-yield regime) the response mechanism of the stress and the strain for composites was investigated, and the von mises stress field of PP/nano-TiO2 composites has also been simulated. It was found that the simulation results are Consistent with the testing results at low volume strain level. The results simulated using the 2D model are accurate with the experimental results. If the volume fraction of particles is less, other particles have little influence on the local stress field of a certain particle, no obvious overlap or cross of the stress field could be found between two neighboring particles. While applying different loads, the stress jumps to maximum stress value in the interaction region of the two phase firstly, and then it occurs that the particles debond with the matrix.

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A New Anchorage Device for Orthodontic Applications

Volume 3A: Biomedical and Biotechnology Engineering ◽

10.1115/imece2013-63973 ◽

2013 ◽

Author(s):

Mohamad Najari ◽

Marwan El-Rich ◽

Samer Adeeb ◽

Bachar Taha

Keyword(s):

Cortical Bone ◽

Shear Force ◽

Vertical Shear ◽

Von Mises Stress ◽

Fe Method ◽

Screw Head ◽

Load Bearing ◽

New Device ◽

Von Mises ◽

Orthodontic Forces

In orthodontic treatment, anchorage is the most important element that affects the treatment’s success. To improve the load bearing capacity of the anchorage there are several devices developed in recent decades such as midpalatal implants and onplants but they also have limitation on directions of applied load and their support position adjustability. The purpose of this study was to investigate the efficiency of a new anchorage device by analyzing the load-bearing and stress distribution among the cortical and cancellous bones of the mandible as well as the anchorage system components using nonlinear 3D Finite Element (FE) method. The new device is composed of an adjustable stainless steel plate equipped with bracket and mounted with two titanium mini-screws into the mandible. The response of this new system was compared to an isolated mini-screw system under different loading scenarios. A maximum of 500gr force was applied in different directions on the bracket and the isolated mini-screw head to simulate the orthodontic loading. Using the new anchorage device reduced von-Mises stress in the whole structure approximately by 50% comparing to the isolated mini-screw. In the cortical bone and depending on the direction of the applied force, von-Mises stress decreased from 6 to 3MPa under vertical shear force and from 6 to 1.5MPa under horizontal and inclined shear forces. In the cancellous bone the stress decreased similarly as in the cortical bone from 0.6 to ≈0.3MPa under horizontal and inclined shear. Under vertical shear force the decrease was less significant from 0.57MPa to 0.5MPa. This new device while offering wide fields of orthodontic forces applications thanks to its bracket provides the same resistive force (500gr) as the isolated mini-screw with much lower stresses in the bone and anchorage implant as well. The next step is to investigate the efficiency of this new device in the teeth movement.

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