scholarly journals Biomechanical analysis of subcondylar fracture fixation using miniplates at different positions and of different lengths

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chao-Min Huang ◽  
Man-Yee Chan ◽  
Jui-Ting Hsu ◽  
Kuo-Chih Su
Keyword(s):  
Fracture Fixation ◽  
Reaction Force ◽  
Fracture Site ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Posterior Portion ◽  
Subcondylar Fracture ◽  
Sliding Distance ◽  
Subcondylar Region

Abstract Background Many types of titanium plates were used to treat subcondylar fracture clinically. However, the efficacy of fixation in different implant positions and lengths of the bone plate has not been thoroughly investigated. Therefore, the primary purpose of this study was to use finite element analysis (FEA) to analyze the biomechanical effects of subcondylar fracture fixation with miniplates at different positions and lengths so that clinicians were able to find a better strategy of fixation to improve the efficacy and outcome of treatment. Methods The CAD software was used to combine the mandible, miniplate, and screw to create seven different FEA computer models. These models with subcondylar fracture were fixed with miniplates at different positions and of different lengths. The right unilateral molar clench occlusal mode was applied. The observational indicators were the reaction force at the temporomandibular joint, von Mises stress of the mandibular bone, miniplate and screw, and the sliding distance on the oblique surface of the fracture site at the mandibular condyle. Results The results showed the efficacy of fixation was better when two miniplates were used comparing to only one miniplates. Moreover, using longer miniplates for fixation had better results than the short one. Furthermore, fixing miniplates at the posterior portion of subcondylar region would have a better fixation efficacy and less sliding distance (5.46–5.76 μm) than fixing at the anterolateral surface of subcondylar region (6.10–7.00 μm). Conclusion Miniplate fixation, which was placed closer to the posterior margin, could effectively reduce the amount of sliding distance in the fracture site, thereby achieving greater stability. Furthermore, fixation efficiency was improved when an additional miniplate was placed at the anterior margin. Our study suggested that the placement of miniplates at the posterior surface and the additional plate could effectively improve stability.

scholarly journals 3D Finite Element Analysis of Rotary Instruments in Root Canal Dentine with Different Elastic Moduli

2021 ◽  
Vol 11 (6) ◽  
pp. 2547 ◽  
Author(s):  
Carlo Prati ◽  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Alexandre Luiz Souto Borges ◽  
Maurizio Ventre ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Root Canal ◽  
Elastic Moduli ◽  
Reaction Force ◽  
Von Mises Stress ◽  
Elastic Behavior ◽  
Element Analysis ◽  
Heat Treated ◽  
Von Mises

The aim of the present investigation was to calculate the stress distribution generated in the root dentine canal during mechanical rotation of five different NiTi endodontic instruments by means of a finite element analysis (FEA). Two conventional alloy NiTi instruments F360 25/04 and F6 Skytaper 25/06, in comparison to three heat treated alloys NiTI Hyflex CM 25/04, Protaper Next 25/06 and One Curve 25/06 were considered and analyzed. The instruments’ flexibility (reaction force) and geometrical features (cross section, conicity) were previously investigated. For each instrument, dentine root canals with two different elastic moduli(18 and 42 GPa) were simulated with defined apical ratios. Ten different CAD instrument models were created and their mechanical behaviors were analyzed by a 3D-FEA. Static structural analyses were performed with a non-failure condition, since a linear elastic behavior was assumed for all components. All the instruments generated a stress area concentration in correspondence to the root canal curvature at approx. 7 mm from the apex. The maximum values were found when instruments were analyzed in the highest elastic modulus dentine canal. Strain and von Mises stress patterns showed a higher concentration in the first part of curved radius of all the instruments. Conventional Ni-Ti endodontic instruments demonstrated higher stress magnitudes, regardless of the conicity of 4% and 6%, and they showed the highest von Mises stress values in sound, as well as in mineralized dentine canals. Heat-treated endodontic instruments with higher flexibility values showed a reduced stress concentration map. Hyflex CM 25/04 displayed the lowest von Mises stress values of, respectively, 35.73 and 44.30 GPa for sound and mineralized dentine. The mechanical behavior of all rotary endodontic instruments was influenced by the different elastic moduli and by the dentine canal rigidity.

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

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.

scholarly journals Biomechanical Design Application on the Effect of Different Occlusion Conditions on Dental Implants with Different Positions—A Finite Element Analysis

2020 ◽  
Vol 10 (17) ◽  
pp. 5826
Author(s):  
Pei-Ju Lin ◽  
Kuo-Chih Su
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Dental Implants ◽  
Dental Implant ◽  
Reaction Force ◽  
Biomechanical Analysis ◽  
Element Analysis ◽  
Group Function ◽  
Implant System ◽  
The Impact

A dental implant is currently the most commonly used treatment for patients with lost teeth. There is no biomechanical reference available to study the effect of different occlusion conditions on dental implants with different positions. Therefore, the aim of this study was to conduct a biomechanical analysis of the impact of four common occlusion conditions on the different positions of dental implants using the finite element method. We built a finite element model that included the entire mandible and implanted seven dental implant fixtures. We also applied external force to the position of muscles on the mandible of the superficial masseter, deep masseter, medial pterygoid, anterior temporalis, middle temporalis, and posterior temporalis to simulate the four clenching tasks, namely the incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), and right group function (RGF). The main indicators measured in this study were the reaction force on the temporomandibular joint (TMJ) and the fixed top end of the abutment in the dental implant system, and the stress on the mandible and dental implant systems. The results of the study showed that under the occlusion conditions of RMOL, the dental implant system (113.99 MPa) and the entire mandible (46.036 MPa) experienced significantly higher stress, and the reaction force on the fixed-top end of the abutment in the dental implant system (261.09 N) were also stronger. Under the occlusion of ICP, there was a greater reaction force (365.8 N) on the temporomandibular joint. In addition, it was found that the reaction force on the posterior region (26.968 N to 261.09 N) was not necessarily greater than that on the anterior region (28.819 N to 70.431 N). This information can help clinicians and dental implant researchers understand the impact of different chewing forces on the dental implant system at different positions after the implantation.

scholarly journals The Influence of Pelvic Tilt on Stress Distribution in the Acetabulum: Finite Element Analysis

2020 ◽  
Author(s):  
Kazuhiro Hasegawa ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Jiro Sakamoto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Hip Joint ◽  
Tilt Angle ◽  
Pelvic Tilt ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Abstract Background Finite element analysis (FEA) has been previously applied for the biomechanical analysis of acetabular dysplasia and osteotomy. However, until now, there have been little reports on the use of FEA to evaluate the effects of pelvic tilt on stress distribution in the acetabulum. Methods We used the Mechanical Finder Ver. 7.0 (RCCM, Inc., Japan) to construct finite element models based on 3D-CT data of patients, and designed dysplasia, borderline, and normal pelvic models. For analysis, body weight was placed on the sacrum and the load of the flexor muscles of the hip joint was placed on the ilium. The pelvic tilt was based on the anterior pelvic plane, and the pelvic tilt angles were -20°, 0°, and 20°. The load of the flexor muscle of the hip joint was calculated using the moment arm equation.Results All three models showed the highest values of von Mises stress in the -20° pelvic tilt angle, and the lowest in the 20° angle. Stress distribution concentrated in the load-bearing area. The maximum values of von Mises stress in the borderline at pelvic tilt angles of -20° was 3.5Mpa, and in the dysplasia at pelvic tilt angles of 0° was 3.1Mpa. Conclusions The pelvic tilt angle of -20° of the borderline model showed equal maximum values of von Mises stress than the dysplasia model of pelvic tilt angle of 0°, indicating that pelvic retroversion of -20° in borderline is a risk factor for osteoarthritis of the hip joints, similar to dysplasia.

Analysis and Evaluating of Flexible Ankle Foot Orthosis for Drop Foot Deformity

2020 ◽  
Vol 398 ◽  
pp. 41-47 ◽  
Author(s):  
Fahad Mohanad Kadhim ◽  
Marfa Salah Hayal
Keyword(s):  
Composite Material ◽  
Reaction Force ◽  
Good Control ◽  
Trunk Muscles ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Experimental Part ◽  
Sound Side ◽  
The Difference ◽  
Von Mises

This work involved two major parts: the first Part is the experimental part included manufacturing ankle foot orthotics, measure the (the reaction force of the ground, pressure distribution) for both normal (healthy) and sound side (intake) legs in two case, the first measurement when the patient walking without orthosis while the second test when the patient dressed up the flexible (AFO). The pressure generated between leg and calf part is measured by F-Socket devise. The experimental part also consist test the mechanical properties of a suggestion composite material. The second Part is the (FEM) finite element analysis for numerical simulation part during which the stresses are calculated using ANSYS 14.5 software. Experimental work was done on a case study suffering from low level spinal cord trauma he has good control of the trunk muscles but the muscle weakness and nerve damage for right leg. The patient with age, weight of 30years, 75kg, respectively. The Results show the parameters of test for both legs (left and right) in two cases. The results show that the data of the gait cycle in the case of the patient wearing the brace is more acceptable and we notice improvement in the performance of walking steps and reduce the difference between the infected leg and natural and this indicates the good evaluation of this orthosis. Max pressure obtained is 1.53*10^5MPa from F .Socket at calf region .Max stress Calculated at Posterior ankle joint because it is flexible Position The equivalent Von-Mises stress and the safety factor for fatigue of the composite material gave good results this led to the longer life design.

scholarly journals Partial Threading of Pedicle Screws in a Standard Construct Increases Fatigue Life: A Biomechanical Analysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1503
Author(s):  
Fon-Yih Tsuang ◽  
Chia-Hsien Chen ◽  
Lien-Chen Wu ◽  
Yi-Jie Kuo ◽  
Yueh-Ying Hsieh ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Pedicle Screw ◽  
Pedicle Screws ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Shaft Length ◽  
Element Analysis ◽  
Screw Design ◽  
Screw Length

This study proposed a pedicle screw design where the proximal 1/3 of the screw is unthreaded to improve fixation in posterior spinal surgery. This design was also expected to reduce the incidence of mechanical failure often observed when an unsupported screw length is exposed outside the vertebra in deformed or degenerated segments. The aim of this study was to evaluate the fatigue life of the novel pedicle screw design using finite element analysis and mechanical testing in a synthetic spinal construct in accordance with American Society for Testing and Materials (ASTM) F1717. The following setups were evaluated: (i) pedicle screw fully inserted into the test block (EXP-FT-01 and EXP-PU-01; full thread (FT), proximal unthread (PU)) and (ii) pedicle screw inserted but leaving an exposed shaft length of 7.6 mm (EXP-FT-02 and EXP-PU-02). Corresponding finite element models FEM-FT-01, FEM-FT-02, FEM-PU-01, and FEM-PU-02 were also constructed and subjected to the same loading conditions as the experimental groups. The results showed that under a 220 N axial load, the EXP-PU-01 group survived the full 5 million cycles, the EXP-PU-02 group failed at 4.4 million cycles on average, and both EXP-FT-01 and EXP-FT-02 groups failed after less than 1.0 million cycles on average, while the fatigue strength of the EXP-FT-02 group was the lowest at 170 N. The EXP-FT-01 and EXP-FT-02 constructs failed through fracture of the pedicle screw, but a rod fractured in the EXP-PU-02 group. In comparison to the FEM-FT-01 model, the maximum von Mises stress on the pedicle screw in the FEM-PU-01 and FEM-PU-02 models decreased by −43% and −27%, respectively. In conclusion, this study showed that having the proximal 1/3 of the pedicle screw unthreaded can reduce the risk of screw fatigue failure when used in deformed or degenerated segments.

scholarly journals Biomechanical Analysis of the Forces Exerted during Different Occlusion Conditions following Bilateral Sagittal Split Osteotomy Treatment for Mandibular Deficiency

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yuan-Han Chang ◽  
Man-Yee Chan ◽  
Jui-Ting Hsu ◽  
Han-Yu Hsiao ◽  
Kuo-Chih Su
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Stress ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Intermaxillary Fixation ◽  
Element Analysis ◽  
Sagittal Split Osteotomy ◽  
Bilateral Sagittal Split Osteotomy ◽  
External Forces

The bilateral sagittal split osteotomy (BSSO) technique is commonly used to correct mandibular deficiency. If the patient is exposed to excessive external forces after the procedure, occlusal changes or nonunion may occur. However, previous studies only focused on single external forces on the mandible and did not conduct relevant research on the forces exerted by different occlusion conditions. The main purpose of this study was to use finite element analysis methods to determine the biomechanics of four common occlusion conditions after BSSO surgical treatment. This study constructed a finite element analysis computer model of a miniplate implanted in the lower jaw. The structure of the model consisted of the mandible, miniplate, and screws. In addition, external forces were applied to the superficial masseter, deep masseter, medial pterygoid, anterior temporalis, middle temporalis, and posterior temporalis muscles to simulate the incisal clench, intercuspal position (ICP), right unilateral molar clench (RMOL), and right group function occlusion conditions. Subsequently, this study observed the effects of these conditions on the miniplate, screws, and mandible, including the von Mises stress values. The results showed that all of the different occlusion conditions that this study evaluated placed high stress on the miniplate. In the ICP and RMOL occlusion conditions, the overall mandibular structure experienced very high stress. The screw on the proximal segment near the bone gap experienced high stress, as did the screw on the buccal side. According to the present analysis, although the data were not directly obtained from clinical practice, the finite element analysis could evaluate the trend of results under different external forces. The result of this study recommended that patients without intermaxillary fixation avoid the ICP and RMOL occlusion conditions. It can be used as a pilot study in the future for providing clinicians more information on the biomechanics of implantation.

scholarly journals Biomechanical Analysis of Clavicle Hook Plates with a Range of Posterior Hook Offsets Implanted at Different Acromion Positions in the Acromioclavicular Joint: A Finite Element Analysis Study

2021 ◽  
Vol 11 (23) ◽  
pp. 11105
Author(s):  
Li-Kun Hung ◽  
Cheng-Hung Lee ◽  
Kuo-Chih Su
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reaction Force ◽  
Biomechanical Analysis ◽  
Hook Plate ◽  
Implant Design ◽  
Element Analysis ◽  
Mechanical Basis ◽  
Biomechanical Effect ◽  
Clavicle Hook Plate

The clavicle hook plate is commonly used in acromioclavicular injuries; however, the biomechanical effect of the posterior hook offset and hook position is unclear. This study applied a finite element analysis (FEA) to evaluate these parameters to improve the clinical strategy. Nine FEA models with 0-mm, 5-mm, and 10-mm posterior hook offsets implanted in the anterior, middle, and posterior acromion were established to evaluate the stress distribution and the reaction force on the acromion. The 5-mm and 10-mm posterior hook offsets at all acromion positions reduced the reaction force on the acromion but slightly increased the stress on the clavicle. The 0-mm offset increased the reaction force at all acromion positions and was relatively lower at the middle acromion. The clavicle hook plate with a posterior hook offset reduces the reaction force on the acromion, providing a flexibility of the hook position. These results provide surgeons with the biomechanical basis for the hook offset and position and engineers with the mechanical basis for the implant design.

scholarly journals Effects of Pentagonal Pore Sizes in the Zinc Hydroxyapatite Parietal-Temporal Implant

2021 ◽  
Vol 11 (11) ◽  
pp. 76-85
Author(s):  
Wan Nur Fatini Syahirah W. Dagang ◽  
◽  
Nik Harisha Qistina Nik Hamdi ◽  
Shahrul Hisyam Marwan ◽  
Jamaluddin Mahmud ◽  
...  
Keyword(s):  
Pore Size ◽  
Mechanical Performance ◽  
Biomechanical Properties ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Pore Sizes ◽  
Alloplastic Materials ◽  
Cranial Implant ◽  
Von Mises

To reconstruct the fractured skull, affected patients are advised to undergo cranioplasty, which is a surgical procedure to repair the cranial defect by implanting materials such as autologous bone grafts or synthetic alloplastic materials. The use of synthetic alloplastic materials such as hydroxyapatite (HA) has been widely accepted due to their biocompatibility and suitability for larger cranial defects. The zinc hydroxyapatite (ZnHA) material is favourable as HA mimics 60% of the actual human bone, whereas zinc helps to improve its biomechanical properties. The purpose of this study is to construct the ZnHA cranial implant with different pore sizes of 600, 900, and 1200 µm in pentagonal shapes and to study its mechanical performance. At the end of the research, it was found that the implant with a pore size of 900 µm is the most appropriate implant to be utilized without affecting its mechanical performance. Aspects such as the deformation and von Mises stress are discussed to assist on the development of the ZnHA cranial implant. Keywords — Biomechanical analysis, cranial implant, finite element analysis, pore size, zinc hydroxyapatite

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