Finite Element Analysis Study Research Articles

Three different screw trajectories in single segment fixation: a finite element analysis and biomechanical study.

Conventional pedicle screw (CPS) fixation in osteoporotic spines presents significant challenges. Cortical bone trajectory (CBT) screws can enhance screw holding power by increasing contact with cortical bone. However, the standard CBT (S-CBT) screws may encounter a series of problems such as stress concentration and diminished fatigue resistance. The S-CBT screw technique has been modified to accommodate longer screws, and the biomechanical behaviors of this modified CBT (M-CBT) screw technique were investigated. A finite element analysis and biomechanical cadaveric study. A validated nonlinearly finite element model spanning L1-S1 was employed in this study. Three L4-5 fusion models, namely CPS, M-CBT, and S-CBT, were generated using interbody fusion cages and different screw fixations. Next, the models were subjected to loading protocols to simulate flexion, extension, lateral bending, and rotation motion. The range of motion (ROM) and peak von Mises stress of the Cage, rods, screws, and intervertebral discs were analyzed. Besides, three types of cadaveric lumbar fusion modes were constructed using diverse screw trajectories. These models were cycled 10,000 times to measure the vertebral body displacement. Afterward, the individual screws were subjected to axial pull-out tests, and the maximum pulling-out force was documented. Finally, the data from the three fusion models were compared. Regarding six degrees of freedom movements, the three fixation models significantly increased the ROM of the adjacent segments (L3-4 and L5-S1) (P < 0.01). However, the differences in ROM increments among the three models were not statistically significant (P = 0.815). The peak von Mises stress of the cage for the M-CBT model was lower by -1.06%, 37.75%, 10.28%, and 17.55% compared with the S-CBT model during flexion, extension, right bending, and left rotation directions, respectively. Similarly, the peak von Mises stress of L5 screws for the M-CBT model was lower by 50.57%, 59.98%, 47.29%, 64.07%, 63.24%, and 50.45% compared with S-CBT during flexion, extension, left bending, right bending, left rotation, and right rotation, respectively. In the biomechanical test, the fatigue displacement results revealed that the displacement of M-CBT model was intermediate between the S-CBT and CPS models under both maximum and minimum forces, with statistically significant differences (P < 0.05). Additionally, the results of the anti-pull-out test following fatigue loads demonstrated that the M-CBT group exhibited the highest maximum pull-out force (Fmax) [381.80 (119.00, 852.20)], followed by the CPS group [329.10 (117.00, 507.80)] and the S-CBT group [321.50 (196.60, 887.20)], but the differences were not statistically significant (P = 0.665) in the upper vertebral subgroup. Conversely, the Fmax of M-CBT group [384.20 (314.00, 851.20)] was significantly higher than that of S-CBT group [264.70 (118.80, 477.40)] and CPS group [282.20 (50.80, 595.20)] in the lower vertebral subgroup, with a significant difference between M-CBT and S-CBT (P = 0.037). M-CBT could enhance the control force of the anterior column of the vertebral body by increasing the inserted screw length, minimizing the stress on the cages and screws, and optimizing the anti-fatigue performance of the internal fixation system compared to S-CBT. M-CBT screw technique shows better biomechanical properties compared to both S-CBT and CPS techniques, providing a more stable and effective internal fixation option for internal fixation in osteoporotic vertebrae.

Biomechanical analysis of a newly designed and 3D printed plate-locking interbody cage: an observational study of finite element analysis

Anterior cervical interbody fusion (ACDF) has become a classic surgical procedure for the treatment of cervical degenerative diseases, and various interbody cages are widely used in this procedure. We used 3D printing technology to produce a new type of plate-locking cage, anticipating to achieve high fusion rate with the high biomechanical stability. This study is to compare the biomechanical characteristics between a newly designed interbody cage and a conventional Zero-profile cage during ACDF using finite element analysis. The CT images of a 35-year-old healthy male were extracted and saved in DICOM format. Mimics Research 19.0, Geomagic Wrap 2017, NX12. 0, Abaqus 6.14 were used to construct the finite element models, then, titanium plate, titanium screw, cages, and the residual parts of both groups were assembled with reference to the surgical approach of ACDF (C4/5), following the successful establishment of both surgical models, a total of six boundary and loading conditions were tested, including flexion, extension, left and right bending, and left and right axial torsion. It is found that the plate stress peak of the new cage group decreased 73.78 MPa, 70.00%; 77.17 MPa, 70.67%; 59.77 MPa, 64.97%; 49.94 MPa, 58.28%; 44.55 MPa, 68.38%; 46.14 MPa, 68.00% in flexion, extension, left bending, right bending, left axial torsion and right axial torsion, respectively. There were no obvious increases of C5 upper endoplate stress peak between these two surgical models (< 50%), except 11.68 MPa, 153.08%; 6.55 MPa, 51.45%; in flexion and extension. The 3D-printed porous plate-locking cage was shown to be biomechanically stable compared to the conventional Zero-profile cage, and it is worth noticing that the stress on the plate of the new cage is less than that on screw of the conventional cage, which indicates that the risk of fracture, loosening, and prolapse of the new cage is less likely to occur.

The interaction between third molars and surrounding periapical tissues in mandibular stress distribution during high-impact trauma: a finite element study.

The presence of mandibular third molars has been associated with the risk of mandibular fractures, highlighting the need for comprehensive studies considering the interaction with other mandibular structures. This study investigates how mandibular third molars and neighboring tissues can influence the structural fragility of the mandible using finite element analysis. A finite element analysis study following the guidelines proposed by RIFEM 1.0 was performed using three previously created mandible models: Model A, without right and left third molars; Model B, without one third molar; Model C, with bilateral presence of third molars. A 2452N force was applied to the right mandibular body in a virtual environment, allowing for a structural analysis of each mandible. Models without third molars and with only one third molar showed similar energy dissipation patterns, contrasting with the model with both third molars. The presence of third molars influenced the magnitude and distribution of stress, highlighting fragility points in specific areas such as the lingual surface, the condyles bilaterally (models without and with one contralateral third molar to trauma), and the distal cervical region of the second molar (third molar absent), as well as significantly showed the path of energy towards the contralateral side of the trauma with a concentration of energy at the contact points of virtually all teeth present immediately after impact. The presence of mandibular third molars influenced the distribution and magnitude of stress within the mandible during a simulated high-impact trauma. Models with third molars exhibit distinct stress patterns, with fragility points appearing in critical areas such as the lingual surface, condyles, and second molar regions. These findings suggest that the presence of third molars increases the structural fragility of the mandible, potentially elevating the risk of mandibular fractures, especially in the context of traumatic impacts.

Evaluation of stress patterns in teeth with endodontic treatment and periapical lesions as abutments for fixed prosthesis: a finite element analysis study

BackgroundExamining stress distributions in abutment teeth with periapical lesions is essential for understanding their biomechanical impact on dental structures and tissues. This study uses finite element analysis (FEA) to evaluate these stress patterns under occlusal forces, aiming to enhance treatment strategies and prosthetic designs.MethodsThree FEA models were created: a healthy mandibular premolar (Model 1), a premolar with a single crown and a lesion repaired using a fiber-post (Model 2), and 3) a premolar with a lesion repaired using fiber-post to support a four-member bridge (Model 3). A 300 N occlusal static stress was given to each model at a 45° angle to the long axis of the tooth, namely at the lingual inclination of the buccal-cusp. Deformation behaviour and maximum equivalent stress distributions were simulated on the all components, including the bony structure for each model.ResultsThe study showed a reduction in equivalent stress levels in trabecular and cortical bone, crown, cementum, and PDL under occlusal force, from Model 1 to Model 3. The Von Mises yield criteria values of the tooth models differed depending on the prosthetic restorations, with the highest value seen in Model 2 (133.87 MPa). Similar locations in all models showed concentrated equivalent stresses for all components. The periapical lesion area exhibited relatively low stress values for Models 2 and 3, at 0.061 MPa and 0.039 MPa, respectively. The largest level of stress was seen in the cervicobuccal areas of the tooth in all models.ConclusionProsthetic restorations on teeth with periapical lesions resulted in varying stress and biomechanical responses in the tooth and surrounding bone tissue. These teeth can serve as abutments in a four-unit bridge when subjected to optimal occlusal stresses, based on the findings.

Mechanical resistance of a mandibular first molar under the influence of different endodontic access cavity design: a 3D finite element analysis study

Biomechanical properties of a mandibular first molar with different cavity designs [traditional access cavities (TEC-I & TEC-II), ninja access cavity (NEC), conservative access cavity (CEC), truss access cavity (Tr-EC), caries-driven access cavity (Cd-EC), caries-driven truss access cavity (Cd-TrEC)] were compared using finite element (FE) analysis. Models were subjected to three different loads. The highest stress distribution was observed on the enamel surface of the Cd-EC design and the dentin surface of the TEC-II. The stress was mainly concentrated on the lingual root surfaces and in the pericervical area. Enlarging the access cavity significantly increased stress distribution on enamel and dentin.

Location or size? A finite element analysis study of necrotic lesion impact on femoral head collapse

BackgroundThe location and size of necrotic lesions are important factors for collapse, The preserved angles (PAs) are divided into anterior preserved angle (APA) and lateral preserved angle (LPA), which could accurately measure the location of necrosis lesion. We used them to evaluate the effect of the location and size of necrotic lesions on collapse by finite element analysis, to offer a framework for evaluating the prognosis of osteonecrosis of the femoral head (ONFH) in clinical settings.Methods3 left hip models were constructed based on CT data. Within each hip model, three necrosis lesion models were modeled, with necrotic tissue volumes of 30%, 50%, and 70% repectively. The ONFH models with LPA of 45.5°, 50.5°, 55.5°, 60.5°, 65.5°, 70.5°, and 75.5° when APA was 60.5°, and ONFH models with APAs of 45.5°, 50.5°, 55.5°, 60.5°, 65.5°, 70.5°, and 75.5° when LPA was 60.5° were Constructed. The maximum von Mises stess of the femoral head and necrotic lesion, as well as the femoral head displacement, were calculated to evaluate the biomechanical effects of these models.Results(1) In models with the same necrotic volume, when APA was 60.5°, the indexes of the LPA < 60.5° models were significantly higher than those of the LPA ≥ 60.5° models (P < 0.05); the differences of the indexes among the LPA ≥ 60.5° models were not statistically significant (P > 0.05). (2) When LPA was 60.5°, the indexes of models with APA < 60.5 ° and APA ≥ 60.5 ° show the same trend as the former. (3) In the models with the same PAs, there was no statistically significant difference in the indexes (P > 0.05).ConclusionThe location of the necrotic lesion exerts a greater impact on femoral head collapse compared with the size of the lesion. The location of the necrosis may deserve more consideration when assessing the risk of collapse in patients with early onset ONFH.

Mechanical behaviour of 3D printed fiber-reinforced soft functional hydrogel composite: Opportunities for biomedical applications

Owing to the unique native properties of cellulose, such as biocompatibility, biodegradability, and excellent mechanical properties, it offers new strategies for designing environment-friendly, cost-effective, and high-mechanically robust hydrogel composites. Herein, we proposed the fabrication of 3D printed nature-inspired cellulose nanofibers (CNFs) reinforced anisotropic functional nanocomposite hydrogel structure.In this hypothetical study, we focuses on to develop nature-inspired 3D-printed Polyacrylamide PAM / Alginate (Alg) based single layered and multilayered laminate hydrogel composites reinforced with anisotropically oriented CNFs and performing finite element (FE) analysis study via implementing measured experimental material properties to explore the CNF reinforcement mechanism in the fiber-reinforced composite hydrogel. The FE modelling and simulation are based on an idealised anisotropic hyperelastic model used to analyse the anisotropic mechanical behaviour of the 3D printed hydrogel composite structure. The computational study of the nature-inspired printed helicoidally layup hydrogel composite construct exhibit enhanced mechanical properties, which offered appreciable stretchability, toughness and anisotropic mechanical behavior.It will assist the design of the more mechanically compliance composite hydrogel structure, making it suitable for load-bearing biomedical applications.

Application of Ultrashort Implants in Posterior Maxilla With Insufficient Bone Height: A Finite Element Analysis.

Implantation of the posterior maxilla with insufficient bone height faces challenges. Studies have shown that the use of ultrashort implants can avoid additional damage. This finite element analysis study aimed to evaluate the impacts of different lengths of ultrashort implants and three surgical approaches on stress, strain, and displacement in the posterior maxilla with varying bone heights. Twelve models of different lengths (3.0, 4.0, 5.0, and 6.0 mm) of ultrashort implants combined with unicortical fixation, bicortical fixation, and transalveolar sinus elevation were established, and conventional implants and short implants were considered as control models. Von Mises stresses within the implants and the sinus floor cortical bone, maximum and minimum principal stresses within the alveolar ridge cortical bone, and the maximum principal strain of the cancellous bone were determined using these models. Additionally, the displacement of the implants was analysed. Stress distribution range and peak values increased as implant length decreased. In the ultrashort implant group, H5L6 exhibited the smallest maximum and minimum principal stresses, 35.77 and 10.66 MPa, respectively. Among groups with different bone heights, 6 mm long implants presented the lowest maximum von Mises stress, whereas 3 mm long implants presented the highest. In the posterior maxilla with bone heights of 3, 4, and 5 mm, the stresses in different lengths of ultrashort implants and surrounding bone tissue were lower than the yield strengths in these areas, and the use of 6 mm-long ultrashort implants combined with osteotome sinus floor elevation can achieve lower stress distribution. This study provides important insights into the biomechanical properties of ultrashort implants combined with three different surgical procedures in severely atrophic maxilla. The 6-mm long implant combined with osteotome sinus floor elevation is most suitable for this area.

Biomechanical Stress Analysis of Overdentures Supported and Retained by Peek Implants and Attachments Using Different Designs : A 3D Finite Element Analysis Study

Biomechanical Stress Analysis of Overdentures Supported and Retained by Peek Implants and Attachments Using Different Designs : A 3D Finite Element Analysis Study

Finite element analysis and experimental study on the sealing performance of low-phenyl silicone rubber sealing rings

PurposeThe brake pipe system was an essential braking component of the railway freight trains, but the existing E-type sealing rings had problems such as insufficient low-temperature resistance, poor heat stability and short service life. To address these issues, low-phenyl silicone rubber was prepared and tested, and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approachThe low-temperature resistance and thermal stability of the prepared low-phenyl silicone rubber were studied using low-temperature tensile testing, differential scanning calorimetry, dynamic thermomechanical analysis and thermogravimetric analysis. The sealing performance of the low-phenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.FindingsThe prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability. According to the finite element analysis results, the finish of the flange sealing surface and groove outer edge should be ensured, and extrusion damage should be avoided. The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments. When the sealing effect was ensured, a small compression ratio should be selected, and rubbers with hardness and elasticity less affected by temperature should be selected. The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature (RT) and −50 °C.Originality/valueThe innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.

Residual dentin thickness and biomechanical performance of post-and-core-restored mandibular premolars: A finite element analysis study.

Endodontically treated teeth often require post-and-core restorations for structural support because of extensive hard tissue loss. Assessment of the effect of the residual dentin thickness on the biomechanical performance of these restorations is lacking. The purpose of this study was to evaluate the residual dentin thickness in mandibular premolars after post-and-core restorations using cone beam computed tomography (CBCT) and to analyze the stress distribution with finite element analysis (FEA). The CBCT data from 236 mandibular premolars having undergone post-and-core restorations were examined. An imaging software program (NNT; NewTom) was used to measure the buccolingual and mesiodistal root diameters in cross-sections 5 to 11mm from the radiologic apex. The CBCT derived measurements were subsequently integrated into an FEA model. A 3-dimensional (3D) mandibular premolar model reflecting the residual dentin thickness was created with a computer-aided design software program (Hypermesh 9.0; Altair Engineering). A static force of 100N was applied directly to the buccal cusp tip at 45, 60, 75, and 90 degrees to the long axis of the tooth, and the stress distribution of dentin was analyzed by using an FEA software program (ANSYS APDL 18.0; Ansys Inc). CBCT analysis showed that the buccolingual root diameter was wider than the mesiodistal diameter and that the residual dentin thickness of the buccal aspect was approximately 0.3mm thinner compared with the lingual aspect along the root. The proportions of residual dentin thickness values in the buccolingual direction of the mandibular premolar teeth no less than 1mm exceeded 96.2% at 5 to 11mm from the apex. The proportions of residual dentin thickness values in the mesiodistal direction of the mandibular premolar teeth >1mm were 92.1% and 88.2% at 11mm from the apex after post space preparation and decreased further to 70.8% and 58.9% at 5mm from the apex. The von Mises stresses of the mandibular premolar model with residual dentin thickness were mainly localized to the cervical area (region C, cervix) and the post apex (region A, apex) in the buccolingual direction. Tensile and compressive stress were concentrated on regions C and A on the buccal and lingual sides, respectively. The actual residual dentin thickness model demonstrated higher maximum tensile stress compared with the 1-mm residual dentin thickness model under various loading conditions. During the process of post space preparation in mandibular premolars, sufficient dentin thickness should be retained in the apical region. The tensile stresses of mandibular premolars after clinical post-and-core restoration were mainly concentrated in the cervical area and the post apex, and the maximum tensile stress value was higher than the ideal 1-mm residual dentin thickness model.

Mechanical Properties of Cobalt Chromium Alloy Manufactured by Direct Energy Deposition Technology

Abstract Cobalt chromium (CoCr), a well-known biocompatible material, is additively manufactured using direct energy deposition (DED) technology in this study. This study investigates some important mechanical characteristics of the additively manufactured CoCr using two different numerical simulation methods in addition to mechanical tests and experiments. Mechanical experiments such as hardness, wear, and flexural bending test were conducted on DED-processed samples. All experiments were also conducted on conventionally processed CoCr specimens for comparison purposes. DED-processed CoCr samples exhibited a complex microstructure with a variety of features such as cellular, columnar, and equiaxed grains within their melt pools. While the DED-processed sample had a lower hardness compared to the conventionally processed one, it exhibited a higher wear resistance. The tensile strength obtained from resonance frequency testing was higher for the DED-processed CoCr sample compared to the conventionally fabricated one. The out-of-plane mechanical strength of CoCr samples was measured by conducting flexural bending test, and the conventional sample showed a higher flexural modulus than the DED sample. The bend tests were also numerically simulated using two different finite element analysis (FEA) procedures. The FEA results for the conventionally processed samples are in good agreement with the ones obtained from the experimental flexural bending test. The results of the FEA studies on the DED-processed samples were within 10-20 % of the experimental ones, showing the potential of numerical methods in estimating this property without the need of mechanical testing.

Effect of geometry on clasp retention force: a finite element analysis study

PurposeThe retention force of a realistic clasp is influenced by multiple, interrelated factors, which complicates the identification of the fundamental relationship between clasp geometry and retention force. While realistic clasps exhibit various shapes, they share basic geometric elements such as length, diameter, and curvature. Simpler geometries are often more conducive to identifying the underlying issues. The aim is to investigate the relationship between clasp geometry and retention force using finite element analysis.MethodsA three-dimensional clasp model was created in ANSYS 19.0 (ANSYS, USA). Two types of models were analyzed: rod-shaped clasps with varying lengths (1–15 mm) and diameters (0.6–1.6 mm), and bending clasps with different base widths (6–12 mm) and heights (0.5–5 mm), all made from cobalt-chromium alloys. For the rod models, stress and retention force were assessed by applying displacement loads and analyzing data with nonlinear regression. For the bending models, a similar analysis was conducted for varying base widths and heights.ResultsMaximum stress consistently concentrated at the clasp base. In rod models, retention force decreased with the third power of length and increased with the fourth power of diameter. For bent specimens, the retention force was approximately inversely proportional to the cube of the base width and inversely proportional to the first power of the height.ConclusionsFinite element analysis revealed distinct functional relationships between clasp geometry and retention force. Further laboratory validation is required.

Evaluation of stress distribution in coronal base and restorative materials: A narrative review of finite element analysis studies

Background: Analyzing the stresses created by functional and parafunctional forces on teeth, bones, soft tissues, and intraoral dental materials is crucial for enhancing the success and development of restorations. Purpose: The purpose of this review is to evaluate studies that examine stress distribution in coronal base and restorative materials using the method of finite element analysis. Review: The three-dimensional finite element analysis method is extensively utilized to study biomechanical behavior and assess stress distribution within dental materials. Numerous studies from 2010 to 2024 have investigated the stress caused by polymerization shrinkage and the distribution of stress in various base and restorative materials. Conclusion: This review emphasizes findings related to stress distribution in coronal base and restorative materials, stressing the importance of considering the elastic modulus and thickness of base materials, and highlighting the need for additional research in this field.

Stability of the Implant–Alveolar Bone Complex According to the Peri-Implant Bone Loss and Bone Quality: A Finite Element Analysis Study

Peri-implant bone loss and bone quality significantly affect the biomechanical stability and long-term success of dental implants. This study used finite element analysis to evaluate the stress distribution and deformation behavior of implants and alveolar bone according to bone loss (0–5 mm) and bone quality (normal and low). A finite element model was implemented based on a three-dimensional mandibular model. The mechanical properties of each component were assigned, and finite element analysis was performed using a static occlusal load. The results showed that progressive bone loss increased von Mises stresses in the implant fixture and surrounding bone, and low-quality bone showed a significant vulnerability to stress concentration. The 2 mm bone loss model showed the maximum stress in cortical bone, and from 3 mm onwards, the stress decreased due to extensive loss of cortical bone. This may be because extensive bone loss causes the implant to lose interface with cortical bone and contact only with cancellous bone. This study confirmed that bone loss and the vulnerability of bone quality may potentially affect implant failure. Continued research is needed to suggest customized implants based on the structural vulnerability of alveolar bone.

Finite element analysis of zygomatic implant positioning protocols with conventional implant configurations

The aim of finite element analysis (FEA) study was to compare two zygomatic implant (ZI) techniques in combination with conventional implants. A FEA model was constituted based on computed tomography data of a patient. ZIs were virtually placed into models with sinus slot or extra sinus techniques combined with two or four conventional implants. Occlusal forces were applied from the buccal direction. The von Mises stress values in implants and the principal stress values in alveolar bone were analyzed. Four conventional implants and the sinus slot technique showed lower stress values. Two ZIs with the sinus slot technique and four conventional implants may be biomechanically safer for atrophic maxilla rehabilitation.

Multilayer Silver-Tin Transient Liquid Phase Bonds: Constitutive Modeling Summary

Transient liquid phase (TLP) bonding technology is one promising joining technique in power electronics as it offers superior thermal, electrical and mechanical characteristics. Multilayer silver-tin (AgSn) foils are common TLP joining configuration because of their improved thermal stability and high melting temperature. In fact, the accurate estimation of the elastic and inelastic mechanical properties of the silver-tin TLP bonds is essential for precise evaluations of the bond's stresses and strains using finite element simulations. This paper aims to summarize the various material constitutive models of the AgSn-TLP interconnects developed by the author and their co-workers over the years. Particularly, the elastic, time-independent, steady-state creep and viscoelasticity mechanical properties are introduced. Additionally, this research incorporates comprehensive finite element analysis (FEA) study to evaluate the mechanical response of the silver-tin TLP die attachment due to thermal and thermomechanical loadings in comparison to other common die attach systems of power modules. The simulation results revealed that the AgSn transient liquid phase bonds have superior resistance to the accumulation of inelastic strains and inelastic strain energy suggesting their high potential of improved fatigue life due to thermomechanical loadings.

Comparative Study of Pseudo-Static Finite Element Analysis and Closed-form Solutions of Circular Tunnels Embedded in Soft Soil and Rock

Comparative Study of Pseudo-Static Finite Element Analysis and Closed-form Solutions of Circular Tunnels Embedded in Soft Soil and Rock

Performance evaluation of a low-cost Ti-Mo-Fe (TMF8) as a replacement for Ti-6Al-4V for internal fixation implants used in mandibular angular fractures: a finite element analysis study

Stainless steel and titanium-based alloys have been the gold standard when it comes to permanent implants and magnesium-based alloys have been the best option for bioresorbable alloys. Ti-6Al-4V, Ti-64, with its 110 GPa Young’s Modulus is the most commonly employed alloy to manufacture biomedical implants used for treatment of fractures of skeleton. Recently, researchers have developed a new low-cost and toxic Vanadium-free alternative to this alloy, Ti-3Mo-0.5Fe at.%, namely TMF8. This alloy has a 25% lesser Young’s Modulus compared to Ti-6Al-4V and also demonstrated acceptable mechanical properties while possessing better cell proliferation results. The lower Young’s Modulus can aid in lowering stress shielding effects while its cytocompatibility could enhance healing. This work, therefore, tries to use finite element analyses to compare these two alloys (Ti-64 and TMF8) from a practical structural point of view to analyse the advantages and disadvantages of this new alloy and how a low-cost biocompatible alternative (TMF8) can actually prove to be a more viable option. The analyses confirm that TMF8 shows almost similar biomechanics performance to Ti-64 alloy (and in acceptable range) in bone plate fixation of mandibular angular fracture treatment.Graphical

Comparison of mechanical stability of modified pedicle screw fixator and unilateral lumbopelvic fixation for treating sacroiliac joint disruption: A finite element analysis study.

This study aimed to investigate the mechanical stability of a modified pedicle screw fixator and compare it with unilateral lumbopelvic fixation for treating sacroiliac joint disruption using finite element simulation technology. The digital model of a normal spine-pelvis-femur containing the main pelvic and lumbar ligaments was established based on computed tomography images. A sacroiliac joint disruption model was built and validated, which was stabilized with the models of a modified pedicle screw fixator or unilateral lumbopelvic fixation. A 400 N follower loading was applied to the lumbar vertebrae for the 2 fixation models to analyze displacement and stress distribution. In addition, the construct stiffness was calculated. The peak amounts of sacral vertical displacement, horizontal displacement, posterior displacement, and overall displacement were 0.70 mm, 0.17 mm, 0.73 mm, and 0.88 mm, respectively, in the modified pedicle screw fixator model, which were less than those in the unilateral lumbopelvic fixation model (1.17 mm, 0.31 mm, 2.21 mm, and 2.29 mm, respectively). Compared with unilateral lumbopelvic fixation, the percentage decreases of the modified pedicle screw fixators were 40.2%, 45.2%, 67.0%, and 61.6%, respectively. The peak stress of the internal fixation and pelvis in the modified pedicle screw fixator model was 351.23 MPa and 39.91 MPa, which has 15.5% and 70.4% lower than in the unilateral lumbopelvic fixation model. The construct stiffness of the modified pedicle screw fixator (571 N/ mm) was 67% better than that of unilateral lumbopelvic fixation (342 N/mm). The finite element simulation results showed that the modified pedicle screw fixator model demonstrated smaller sacral displacement, fewer stresses on the internal fixation and bone, and higher construct stiffness compared with the unilateral lumbopelvic fixation model. Thus, the modified pedicle screw fixator may provide biomechanical advantages over unilateral lumbopelvic fixation in the treatment of sacroiliac joint disruption.