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• A system of Digital jaw adjustment and customized splint design with FEM for the patient with TMD were provided; • Overloading on the TMJ may somehow be related with the displacement of the articular disc based on FEM in current research; • The customized splint provided a significant reduction of TMJ stress; • The process of designing customized splint has been validated by postoperative CT images. The mechanical overloading of temporomandibular joint (TMJ) is generally linked to temporomandibular disorders (TMD). However, in patients with a typical combination of maxillofacial morphology and occlusal features, the reduction of joint load and treatment with general occlusal splints are often ineffective. This study investigates the biomechanical behavior of the stomatognathic system in a TMD patient with personalized splints by finite element analysis. The therapeutic position, determined based on the intercuspal position, served as the basis for designing personalized customized splints. The design of occlusal contact and splint structure was evaluated in terms of their impact on the maximum stress level in the TMJ and the biting forces on the dentition. The relationship between joint stress and biting force was further examined during treatment with different customized splints. In preoperative case, there was a significant increase in stress level and stress concentration in the medial to posterior band of the articular disc. However, in all customized splint cases, the highest stress area shifted to the intermediate zone and exhibited a decrease. Notably, the bi-splints demonstrated superior ability in relieving overloading and balancing the occlusal force on both sides of the dentition, as verified by clinical treatment. The predictable simulated results offer valuable interactive information regarding TMJ overload, aiding doctors in making better-informed clinical decisions in future. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the biomechanical behavior of three-dimensionally (3D)-printed surgical plates used for mandibular defect reconstruction, compare them with conventional surgical plates, and provide experimental evidence for their clinical application. Three-dimensional models were created for the normal mandible and for mandibular body defects reconstructed using free fibula and deep circumflex iliac artery flaps. Three-dimensional finite element models of reconstructed mandibles fixed using 3D-printed and conventional surgical plates were established. Vertical occlusal forces were applied to the remaining teeth and the displacement and Von Mises stress distributions were studied using finite element analysis. The normal and reconstructed mandibles had similar biomechanical behaviors. The displacement distributions for the surgical plates were similar, and the maximum total deformation occurred at the screw hole of the anterior segment of the surgical plates. However, there were differences in the Von Mises stress distributions for the surgical plates. In reconstructed mandibles fixed using 3D-printed surgical plates, the maximum equivalent Von Mises stress occurred at the screw hole of the posterior segment, while in those fixed using conventional surgical plates, the maximum equivalent Von Mises stress was at the screw hole of the anterior segment. In the mandible models reconstructed with the same free flap but fixed with different surgical plates, the plates had similar biomechanical behaviors. The biomechanical behavior of 3D-printed surgical plates was similar to conventional surgical plates, suggesting that 3D-printed surgical plates used to reconstruct mandibular body defects with vascularized autogenous bone grafts could lead to secure and stable fixation. [ABSTRACT FROM AUTHOR]

Objective: The objective of this investigation is to assess the material qualities of lumbar vertebrae and their influence on biomechanical characteristics. Methodology: The study examined four distinct sets of material qualities, which were characterised by different values of Young's modulus and Poisson's ratio for both trabecular and cortical bone. The analysis focused on examining the impact of different material property sets on stress distribution, displacement, and strain patterns. In order to substantiate the results, a three-dimensional model of the lumbar vertebrae was generated utilising computed tomography (CT) data and subsequently submitted to finite element analysis. Results: The findings of the study are as follows: The findings of the study indicated that there were discernible variations in stress distributions across different material property sets. Specifically, it was consistently observed that areas 2 and 3 displayed elevated stress values compared to other regions. The study observed a decrease in maximum displacement as the material features were stiffer. Specifically, Set 4 exhibited the lowest displacement while Set 1 exhibited the most. While there were certain changes in strain patterns among different material property sets, these variations were not as substantial when compared to the distributions of stress and displacement. The investigation underscored the notable impact of material attributes on the biomechanical characteristics of lumbar vertebrae. Increased material strength led to elevated stress concentrations and decreased displacements. The findings also demonstrated that there was no stress observed in any of the vertebrae. However, it was observed that Set 2 had the highest pressure value. Comprehending the impact of material qualities on the biomechanics of lumbar vertebrae is of paramount importance in the development of efficacious interventions and preventative strategies for disorders pertaining to the spine. Conclusion: In conclusion, the Young's modulus and Poisson's ratio were found to be significant factors in determining stress concentration and displacement. Specifically, lower values of Poisson's ratio and Young's modulus were observed to correspond to increased stress concentration and decreased displacement. [ABSTRACT FROM AUTHOR]

• Biomechanical behavior of supracondylar fractures depends on plate length and screw configuration. • Shorter plates provide more stable osteosyntheses than longer plates. • For longer plates, it is more convenient disposing screws in a way that the upper ones are closer to fracture site. • Stability in the immediately post-operative is essential for fracture consolidation. • The study can help surgeons to find the most appropriate osteosynthesis depending on the fracture type. Distal femoral fractures are fractures associated with high rates of morbidity and mortality, affecting to three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. They have been classically treated with conventional plates and intramedullary nails and more recently with locked plates that have increased their indications to more types of fractures. The main objective of the present work is the biomechanical study, by means of finite element simulation, of the stability achieved in the osteosynthesis of femoral fractures in zones 4 and 5 of Wiss, by using locked plates with different plate lengths and different screw configurations, and analysing the effect of screw proximity to the fracture site. A three dimensional (3D) finite element model of the femur from 55-year-old male donor was developed, and then a stability analysis was performed for the fixation provided by Osteosynthesis System LOQTEC® Lateral Distal Femur Plate in two different fracture zones corresponding to the zones 4 and 5 according to the Wiss fracture classification. The study was focused on the immediately post-operative stage, without any biological healing process. The obtained results show that more stable osteosyntheses were obtained by using shorter plates. In the cases of longer plates, it results more convenient disposing screws in a way that the upper ones are closer to fracture site. The obtained results can support surgeons to understand the biomechanics of fracture stability, and then to guide them towards the more appropriate osteosynthesis depending on the fracture type and location. [ABSTRACT FROM AUTHOR]

The biomechanical behavior of the universal link (titanium base) prosthetic abutment with different heights in implant-supported restorations was evaluated. Forty regular implants (4 × 10 mm) in titanium were used, divided into two groups according to the abutment height (n = 20): 4.5 × 4 mm (short) and 4.5 × 5.5 mm (long). Using CAD/CAM technology, zirconia crowns were milled and cemented onto the prosthetic abutments. Half of the specimens were submitted to the initial maximum fracture load test in a universal testing machine. The long abutments presented fracture load (41.1 ± 6.96 kgf) statistically similar to the short abutments (49.5 ± 7.68 kgf). The other half of the specimens were submitted to mechanical cycling (2,000,000 cycles, 2 Hz with a stainless-steel antagonist with a diameter of 1.6 mm), following ISO 14801:2007. Subsequently, the survival of the specimens was evaluated using the survival analysis function, Kaplan–Meier and Mentel–Cox (log- rank) (p < 0.05). The finite element analysis was performed in similar conditions to those used for the in vitro test through computer-aided engineering software (version 19.2, ANSYS Inc., Houston, TX, USA). The biomechanical behavior of both models was similar regardless of the evaluated structure of the set. It was concluded that both short and long abutment presents promising fatigue behavior and stress distribution for use in long-term implant-supported restorations. [ABSTRACT FROM AUTHOR]

The interosseous membrane (IOM) of the forearm plays a crucial role in facilitating forearm function and mechanical load transmission between the radius and ulna. Accurate characterization of its biomechanical properties is essential for developing realistic finite element models of the forearm. This study aimed to investigate the mechanical behavior and material properties of the central fibrous regions of the IOM using fresh frozen cadavers. Ten forearms from five cadavers were dissected, preserving the IOM and identifying the distal accessory band (DAB), central band (CB), and proximal accessory band (PAB). Bone-ligament-bone specimens were prepared and subjected to uniaxial tensile testing, with the loading direction aligned with the fiber orientation. Force-displacement curves were obtained and converted to force-strain and stress–strain curves using premeasured fiber lengths and cross-sectional areas. The results demonstrated distinct mechanical responses among the IOM regions, with the PAB exhibiting significantly lower force-strain behavior compared to the DAB and CB. The derived force-strain and stress–strain relationships provide valuable insights into the regional variations in stiffness and strength of the IOM, highlighting the importance of considering these differences when modeling the IOM in finite element analysis. In conclusion, this study establishes a foundation for the development of advanced finite element models of the forearm that accurately capture the biomechanical behavior of the IOM. [ABSTRACT FROM AUTHOR]

There is considerable biomechanics literature on finite element modeling and analysis of the spine. To accurately mimic the biomechanical behavior of the vertebral column, a generated computational model has to include anatomical structures that are consistent with physiological reality. In this review article, we focused on the finite element spine models that have been developed by various approaches in the literature. Firstly, the anatomical features of the spine and the spinal components have been briefly explained. We then focused on the modeling stages of vertebrae, ligaments, facet joints, intervertebral discs, and spinal instruments. With this paper, we expect to provide a comprehensive resource regarding the modeling preferences used in spine modeling. [ABSTRACT FROM AUTHOR]

BACKGROUND: Patients with mild knee osteoarthritis are prone to induce pain and aggravation of arthritis during daily gait walking. At present, the changes in the biomechanical behavior of the internal knee joints of such patients under the gait flexion angle are not very clear. There are few reports in the literature. OBJECTIVE: Based on the proven finite element model of the mild osteoarthritis knee joint, according to the change of gait cycle and knee flexion angle, to simulate the knee flexion behavior at four angles of 0°, 10°, 20°, and 30°, and to study the stress distribution characteristics and contact area changes of femoral cartilage, tibial cartilage, and meniscus. METHODS: The material properties of the finite element model of the mild osteoarthritis knee joint were defined. The boundary conditions and the axial load were determined under different knee flexion angles. By analyzing the Mises stress, Tresca stress, and contact area of the non-bone tissue in the tibiofemoral joint, the biomechanical behavior changes inside the knee joint were studied. RESULTS AND CONCLUSION: The results of finite element analysis showed that as the knee flexion angle increased, the peak Mises stress and the peak Tresca stress on the meniscus, femoral cartilage, and tibial cartilage showed a relatively increasing trend. The total contact area of the tibiofemoral joint showed a decreasing trend, and the medial meniscus subluxation caused the lateral peak to be larger than the medial peak. Meanwhile, the contact area of the medial compartment decreased and the contact area of the lateral compartment increased. When the knee flexion angle reached 20° and 30°, the peak of Mises stress and the peak of Tresca stress appeared. Results showed that when the knee flexion angle of the mild osteoarthritis knee joint changed, the internal stress and contact area change characteristics changed because of the medial meniscus subluxation. The medial contact area decreased; the peak stress increased; and the lateral contact area increased. The peak stress increased and the increase was greater than the inside. The breakdown of the internal load balance of the joint may increase the risk of articular cartilage degeneration and promote the aggravation of knee osteoarthritis. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this study is to develop a FE model of the temporomandibular joint (TMJ) to investigate a musculoskeletal System of forces able to taking into account the effect of all the muscles on the TMJ in terms of stress evaluated on the bone. Methods: A 3-dimensional finite element model of the mandible was constructed from the images generated by cone-beam computed tomography of a patient undergoing fixed orthodontic treatment. In order to define the loading force system an exustive study was developed to investigated the entity of the Lateral pterygoid, Masseter, medial pterygoid, Temporalis, and Geniohoid digastric, muscles. Results: Stresses in the TMJ components (disc, mandible condyle and the fossa eminence on the skull) were obtained. The results have shown stress distribution during normal occlusion. Conclusion: An appreciation of the anatomical and mechanical features associated with the TMJ can serve as a foundation for understanding a patient's clinical presentation. Performance of a thorough patient history and clinical examination can guide the clinician toward an improved diagnostic process. [ABSTRACT FROM AUTHOR]

• 3D finite element models were constructed for finite element analysis. • The occlusal loading force was applied on the prosthetic abutments. • The biomechanical behavior of the system was investigated. • Model 01 presented the best biomechanical behavior in the peri-implant bone. In a dental implant/bone system, the design factors affect the value and distributions of stress and deformations that plays a pivotal role on the stability, durability and lifespan of the implant/bone system. The aim of this study was to compare the influence of different abutment designs on the biomechanical behavior of one-piece zirconia dental implants and their surrounding bone tissues using three-dimensional finite element analysis. A three-dimensional geometrical model of a zirconia dental implant and its surrounding bone tissue were created. The occlusal loading force applied to the prosthetic abutments was a combination of 114.6 N in the axial direction, 17.1 N in the lingual direction and 23.4 N toward the mesial direction where these components represent masticatory force of 118.2 N in the angle of approximately 75° to the occlusal plane. The system included implant abutment Model 01 showed a decrease of 9.58%, 9.92% and 3.62% at least in the average value of maximum von Mises stress compared to Model 02, Model 03 and Model 04 respectively. The results also showed that the system included implant abutment Model 01 decreases the average value of maximum deformation of 16.96%, 7.17% and 9.47% at least compared to Model 02, Model 03 and Model 04 respectively. The one-piece zirconia dental implant abutment Model 01 presents a better biomechanical behavior in the peri-implant bone than others. It can efficiently distribute the applied load and present more homogeneous behavior of stress distribution and has less deformation than others, which will enhance the stability of implant/bone system and prolong its lifespan. [ABSTRACT FROM AUTHOR]

Purpose: To compare equivalent and contact stresses in a mandibular molar restored by all‐ceramic crowns through two methods: ceramic endocrowns and ceramic crowns supported by fiber‐reinforced composite (FRC) posts and core, by using 3D finite element analysis during normal masticatory load. Materials and Methods: Three 3D models of a mandibular first molar were made and labeled as such: intact molar with no restoration (A); ceramic endocrown‐restored molar (B); ceramic crown supported by FRC posts and core restored molar (C). By using 3D FE analysis with contact components, normal masticatory load was simulated. The mvM stresses in all models were calculated. Maximal mvM stresses in the ceramic of restorations, dentin, and luting cement were contrasted among models and to values of materials' strength. Contact shear and tensile stresses in the restoration/tooth interface around restorations were also calculated. Results: The highest mvM stress levels in the enamel and dentin for the tooth restored by ceramic endocrown were lower in the crown ceramic than in tooth restored with FRC posts and all‐ceramic crowns; however, in the resin adhesive cement interface it was lower for ceramic crown supported by FRC posts than the in ceramic endocrown restoration. The maximum contact shear and tensile stress values along the restoration/tooth interface of ceramic endocrowns were lower than those with ceramic crowns supported by FRC posts. Conclusions: Ceramic endocrown restorations presented a lower mvM stress level in dentin than the conventional ceramic crowns supported by FRC posts and core. Ceramic endocrown restorations in molars are less susceptible to damage than those with conventional ceramic crowns retained by FRC posts. Ceramic endocrowns properly cemented in molars must not be fractured or loosen during normal masticatory load. Therefore, ceramic endocrowns are advised as practicable, minimally invasive, and esthetic restorations for root canal treated mandibular molars. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Ceramic fracture and debonding are the primary failures that follow ceramic inlay and can lead to stress and tooth fracture. In this study, we examined two designs—concave and flat—of the gingival cavity bottom for tooth cavities restored using ceramic inlays. We investigated the biomechanical behavior of ceramic inlay–restored teeth (concave and flat) through three-dimensional finite element analysis (FEA) and experimentally validated the results using an ultrahigh-speed camera. We conducted in vitro real-time recording of the deformation of a restored tooth during loading using an ultrahigh-speed camera. This technique enables further image registration to observe deformation variation and vector fields. The deformation vector fields revealed that the concave design moved the deformation toward the buccal side of the cavity bottom, whereas the flat design moved it toward the palatal side. These findings correlated with the FEA results, which indicated that the concave design constrained stress in the dentin cavity and relieved palatal stress. Our results suggest that incorporating a concave design in cavity preparation can improve the fracture resistance of ceramic inlay–restored teeth, preventing unrestorable fractures. The current study is the first to utilize an ultrahigh-speed camera in dental biomechanics, and such cameras are useful for nondestructive and dynamic analysis. Statement of Significance First utilize ultrahigh-speed cameras in dental biomechanics analysis. Tooth fracture videos captured by ultrahigh-speed camera helps us learn fracture mechanics in between tooth cavity design and ceramic inlay. Concave design leads to stress in safer areas that causes a less damaging fracture. Minimal invasive preparation by concave design strengthens tooth fracture resistance. Non-destructive data from ultrahigh-speed cameras combined with FEA can get more insight into how the stress and strain derived in biomaterials. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present study was to investigate the biomechanical behaviors of the pre-shaped titanium (PS-Ti) cranial mesh implants with different pore structures and thicknesses as well as the surface characteristics of the three-dimensional printed Ti (3DP-Ti) cranial mesh implant. The biomechanical behaviors of the PS-Ti cranial mesh implants with different pore structures (square, circular and triangular) and thicknesses (0.2, 0.6 and 1 mm) were simulated using finite element analysis. Surface properties of the 3DP-Ti cranial mesh implant were performed by means of scanning electron microscopy, X-ray diffraction and static contact angle goniometer. It was found that the stress distribution and peak Von Mises stress of the PS-Ti cranial mesh implants significantly decreased at the thickness of 1 mm. The PS-Ti mesh implant with the circular pore structure created a relatively lower Von Mises stress on the bone defect area as compared to the PS-Ti mesh implant with the triangular pore structure and square pore structure. Moreover, the spherical-like Ti particle structures were formed on the surface of the 3DP-Ti cranial mesh implant. The microstructure of the 3DP-Ti mesh implant was composed of α and rutile-TiO 2 phases. For wettability evaluation, the 3DP-Ti cranial mesh implant possessed a good hydrophilicity surface. Therefore, the 3DP-Ti cranial mesh implant with the thickness of 1 mm and circular pore structure is a promising biomaterial for cranioplasty surgery applications. Highlights • The Von Mises stress significantly decreased as the Ti mesh implants with the thickness of 1 mm. • The Ti mesh implant with the circular pore structure exhibited a relatively lower Von Mises stress. • The microstructure of the 3D printed Ti mesh implant was composed of α and rutile-TiO 2 phases. • The 3D printed Ti mesh implant possessed a well hydrophilicity surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design and simulation by FEM of customized scaffolds fixed to the jaw by a dental implant. • Distribution of stress in crown, dental implant, scaffold, cortical and trabecular bone, and strain in the cortical and trabecular bone. • Influence of the porosity and hole size of the scaffolds on the stress and strain in the cortical and trabecular bone. • The use of customized scaffolds allows a significant reduction in stresses and strain in the peri-implant cortical bone. Teeth loss due to periodontal diseases, trauma, or infections often causes dimensional loss in the affected maxillary. In patients with reduced maxillary size, restoration of chewing function and esthetics with endosseous dental implants may fail. The aim of this work was to simulate the biomechanical behavior, using the finite element method, of customized scaffolds fixed by a dental implant on a partially edentulous jaw. Porous scaffolds were designed from medical images of a partially edentulous jaw with type IV bone quality. The influence of the diameter of the hole and the porosity of the scaffold on the maximum levels of stress and strain in the peri -implant bone was evaluated. The highest stress values in the scaffolds, dental implant, and crown were lower than the yield strength of their respective materials. The customized scaffolds allow to recover the dimensions of the evaluated jaw. A significant decrease in stress and strain values was observed in the peri -implant cortical bone. Furthermore, it was found that the evaluated parameters did not have a significant influence on the maximum von Mises equivalent stress and maximum strain values in the peri -implant bone. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of graded models on the biomechanical behavior of a bone-implant system under osteoporotic conditions. Methodology: A finite element model (FEM) of the jawbone segments with a titanium implant is used. Two types of models (a graded model and a non-graded model) are established. The graded model is established based on the graded variation of the elastic modulus of the cortical bone and the non-graded model is defined by homogeneous cortical bone. The vertical and oblique loads are adopted. The max von Mises stresses and the max displacements of the cortical bone are evaluated. Results: Comparing the two types of models, the difference in the maximum von Mises stresses of the cortical bone is more than 20%. The values of the maximum displacements in the graded models are considerably less than in the non-graded models. Conclusions: These results indicate the significance of taking into account the actual graded properties of the cortical bone so that the biomechanical behavior of the bone-implant system can be analyzed accurately. [ABSTRACT FROM AUTHOR]

In the literature, many researchers investigated static loading effects on an implant. However, dynamic loading under impact loading has not been investigated formally using numerical methods. This study aims to evaluate, with 3D finite element analysis (3D FEA), the stress transferred (maximum peak and variation in time) from a dynamic impact force applied to a single implant-supported prosthesis made from different materials. A 3D implant-supported prosthesis model was created on a digital model of a mandible section using CAD and reverse engineering. By setting different mechanical properties, six implant-supported prostheses made from different materials were simulated: metal (MET), metal-ceramic (MCER), metal-composite (MCOM), carbon fiber-composite (FCOM), PEEK-composite (PKCOM), and carbon fiber-ceramic (FCCER). Three-dimensional FEA was conducted to simulate the collision of 8.62 g implant-supported prosthesis models with a rigid plate at a speed of 1 m/s after a displacement of 0.01 mm. The stress peak transferred to the crown, titanium abutment, and cortical bone, and the stress variation in time, were assessed. [ABSTRACT FROM AUTHOR]