Mechanical Stress Research Articles

Modified xanthan gum (natural polymeric material) and its derivative for wastewater treatment: A review

AbstractNaturally occurring xanthan gum (XG) has much commercial importance because of its excellent physicochemical, eco‐friendly, and non‐toxic properties. It is used in various applications like protein extraction, wastewater treatment, tissue engineering, drug delivery, food packaging, and so forth. XG is a natural material, and it has some limitations related to the mechanical stress, thermal stability, and hydration. To overcome the limitation, XG can be modified by adding third component or modification of operation for specific applications. XG can be modified by physical, genetically, enzymatically, or chemical processes. Revamped XG also enhances the efficiency toward adsorbing toxic metal ions and organics from synthetic or industrial effluents. The emphasis of present review article is to address the structural characteristics along with the focus on the developing chemically modified XG like grafted, cross‐linked, nanocomposites, and functionally modified biopolymer. However, this review commences thorough discussion on numerous ways of modifications, which can be attempted in XG structure, expanding its applications for heavy metal ion along with dye removal.

Cyclic compressive loading induces a mature meniscal cell phenotype in mesenchymal stem cells with an atelocollagen-based scaffold

Introduction: Biomechanical stimulation is reportedly pivotal in meniscal regeneration, although its effect on mesenchymal stem cell (MSC) meniscal differentiation remains elusive. In this study, we investigated how cyclic compressive loading (CCL) could impact MSCs using three-dimensional cultures in atelocollagen-based meniscal substitute (ACMS).Methods: We extracted MSCs from the meniscus, synovium, and articular cartilage, cultured them in three-dimensional cultures, and exposed them to CCL for 7 days. We then compared the transcriptomes of MSCs treated with and without CCL.Results: Our RNA-seq analysis revealed that CCL induced significant transcriptome changes, significantly affecting chondrocyte-related genes, including SOX9, TGFB1, and PRG4 upregulation. CCL induced transcriptional differentiation of meniscus progenitors toward mature meniscal cells.Conclusion: This study unveils the potential of mechanical stress in promoting MSC meniscal differentiation within ACMS. Our investigations provide new insights for mechanisms underlying meniscal regeneration with ACMS.

Ferroelasticity in Two-Dimensional Hybrid Ruddlesden-Popper Perovskites Mediated by Cross-Plane Intermolecular Coupling and Metastable Funnel-like Phases.

Ferroelasticity is a phenomenon in which a material exhibits two or more equally stable orientation variants and can be switched from one form to another under an applied stress. Recent works have demonstrated that two-dimensional layered organic-inorganic hybrid Ruddlesden-Popper perovskites can serve as ideal platforms for realizing ferroelasticity, however, the ferroelastic (FE) behavior of structures with a single octahedra layer such as (BA)2PbI4 [BA = CH3(CH2)3NH3+] has remained elusive. Herein, by using a combined first-principles and metadynamics approach, the FE behavior of (BA)2PbI4 under mechanical and thermal stresses is uncovered. FE switching is mediated by cross-plane intermolecular coupling, which could occur through multiple rotational modes, rendering the formation of FE domains and several metastable paraelastic (PE) phases. Such metastable phases are akin to wrinkled structures in other layered materials and can act as a "funnel" of hole carriers. Thermal excitation tends to flatten the kinetic barriers of the transition pathways between orientation variants, suggesting an enhanced concentration of metastable PE states at high temperatures, while halogen mixing with Br raises these barriers and conversely lowers the concentration of PE states. These findings reveal the rich structural diversity of (BA)2PbI4 domains, which can play a vital role in enhancing the optoelectronic properties of the perovskite and raise exciting prospects for mechanical switching, shape memory, and information processing.

Jasmonates Play an Important Role in Differential Accumulation of Key Oolong Tea Aromas in Two Tea Varieties (Camellia sinensis)

Aroma is an important factor in the measurement of the quality and market value of oolong tea. However, it is hard to develop an oolong tea with good aroma quality using unsuitable tea varieties. To explore the key factors of tea varieties in the formation of oolong tea aromas, the fresh leaves of the Chungui variety (CG, suitable for oolong tea, Camellia sinensis (L.) O. Kuntze) and the Fuyun No. 6 variety (F6, unsuitable for oolong tea, Camellia sinensis (L.) O. Kuntze) were harvested and treated by withering and mechanical stress in order. Then, aroma, transcriptome, and jasmonate (JA) contents, and weighted gene co-expression network analysis (WGCNA), of samples were investigated. The contents of characteristic oolong tea aromas, including indole, (E)-β-ocimene, (E)-nerolidol, α-farnesene, and jasmine lactone, were all accumulated in much higher quantities in the CG variety after withering and mechanical stress. Accordingly, the coding genes of aroma formation synthases TSB2, OCS, NES, AFS, and LOX1, and related genes in MVA, MEP, and ALA pathways, were all much more highly activated. These differential reactions are mainly caused by the higher accumulation of jasmonates, especially methyl jasmonate, a type of important plant signal chemical, in CG after mechanical stress. WGCNA analysis indicated 34 different transcription factors from different families are predicted to be involved in this jasmonate-responsive reaction.

O08 Exploring the effect of skin ageing-related basement membrane collagen loss on nuclear mechanics

Abstract Introduction and aims Skin ageing is a universal process that can increase susceptibility to inflammation and disease. Basement membrane collagens (BMCs) are reduced during ageing and the consequences are poorly understood. BMC sensing of mechanical stress, vital for skin homeostasis, elicits signalling sensed via cytoskeletal actin filaments to the linker of nucleoskeleton and cytoskeleton (LINC) complex (composed of nesprin and sun proteins), nuclear lamina and lamina-associated chromatin. Our hypothesis is that BMC loss during ageing leads to a deformation of the nucleocytoskeleton and disrupts chromatin organization in keratinocytes, leading to impairment of epidermal differentiation and inability to withstand mechanical stress. Methods To explore the role of BMC in mechanical stress response, stable lentiviral short hairpin (sh)RNA knockdowns of Col7 (shCol7) and Col17 (shCol17) were generated in immortalized N/TERT keratinocytes. Western blot (WB) validated knockdowns were compared with shC nontargeting control. IncuCyte assays showed shCol17 had a hyperproliferative phenotype compared with shC. Sun2 was reduced in shCol17 (P < 0.001) compared with shC (n = 5 experimental replicates). The mechanical stretch effect on cells on a flexible membrane was studied using immunofluorescence and WB analysis. Images taken from the IN Cell Analyzer confocal microscope were analysed to detect changes in protein expression and localization. Nuclear and cytoplasmic fractions made before and after stretch were analysed by WB. Results We observed collagen-specific responses to stretch-induced stress with changes to actin, components of the nuclear membrane, and LINC complex proteins. Additionally, work on investigating chromatin changes with BMC knockdown using Cleavage Under Targets & Tagmentation and Cleavage Under Targeted Accessible Chromatin assays is ongoing. Conclusions Our data show an altered nucleocytoskeleton in the context of BMC loss and mechanotransduction in skin. These data could provide novel insights into epidermal regulation by BMC in ageing.

Conformal Low Temperature Molecular Layer Deposited Coatings as Interface Modifications to Support Ceramic Protective Films on Macroscopic Flexible Devices

Flexible devices often need a protective coating when operating in harmful environments, ranging from mild ambient conditions to a biologically active environment of the human body. The flexibility poses a problem for traditional encapsulation solutions, as those make the device bulky and limit functionality by applying an external casing. Alternatively, fully conformal encapsulation of a device of arbitrary shape can be realized with thin film encapsulation (TFE) without altering device dimensions. Yet TFE is susceptible to fail under mechanical stresses, especially when a hard ceramic coating is applied on a polymer. Reliability of TFE can be enhanced by altering the elasticity of the hard and brittle thin films, by adding softer layers in between sample and barrier. In this work, molecular layer deposited (MLD) metal‐linked trioxysilylheptanoate (M‐TOSH) films are studied for coating of large devices to conformally and uniformly tune the interface between polymer and atomic layer deposited protective film. The results show that M‐TOSH process scales to large chambers, parameter optimization leads to superior film quality and lowers elastic modulus. Conformality, tested with home‐built macroscopic test device, found the process suitable for 3D parts. Final testing revealed that 10 cycles of MLD‐interlayer doubled the crack‐onset‐strain from 0.26% to 0.51%.This article is protected by copyright. All rights reserved.

Directed biomechanical compressive forces enhance fusion efficiency in model placental trophoblast cultures.

The syncytiotrophoblast is a multinucleated structure that arises from fusion of mononucleated cytotrophoblasts, to sheath the placental villi and regulate transport across the maternal-fetal interface. Here, we ask whether the dynamic mechanical forces that must arise during villous development might influence fusion, and explore this question using in vitro choriocarcinoma trophoblast models. We demonstrate that mechanical stress patterns arise around sites of localized fusion in cell monolayers, in patterns that match computational predictions of villous morphogenesis. We then externally apply these mechanical stress patterns to cell monolayers and demonstrate that equibiaxial compressive stresses (but not uniaxial or equibiaxial tensile stresses) enhance expression of the syndecan-1 and loss of E-cadherin as markers of fusion. These findings suggest that the mechanical stresses that contribute towards sculpting the placental villi may also impact fusion in the developing tissue. We then extend this concept towards 3D cultures and demonstrate that fusion can be enhanced by applying low isometric compressive stresses to spheroid models, even in the absence of an inducing agent. These results indicate that mechanical stimulation is a potent activator of cellular fusion, suggesting novel avenues to improve experimental reproductive modelling, placental tissue engineering, and understanding disorders of pregnancy development.

Piezoresistive sensitivity enhancement below threshold voltage in sub-5 nm node using junctionless multi-nanosheet FETs.

In this paper, the piezoresistive sensitivity is enhanced by applying uniform mechanical stress (MS) on the multi-nanosheet (NS) channels of sub-5 nm junctionless field-effect transistors (FETs). The piezoresistivity of the sensing device is boosted by narrowing channel conductivity using low gate biasing and reducing physical channel width, resulting in the maximum (~6 times higher) sensitivity observed in the subthreshold regime compared to the ON-state condition. In addition, the sensitivity is extensively increased by ~30.3% near the threshold voltage (VTH) with horizontally multi-NS stacking due to the uniform MS distribution on the multi-NS channels, which can sense slight deflection of pressure on the circular diaphragm. These results show that the tunable sensitivity of junctionless multi-channel devices is superior to the inversion mode, a consequence of the less scattering effect, better thermal stability, and low electronic noise.

A Multidisciplinary Evaluation of Three-Dimensional Polycaprolactone Bioactive Glass Scaffolds for Bone Tissue Engineering Purposes

In the development of bone graft substitutes, a fundamental step is the use of scaffolds with adequate composition and architecture capable of providing support in regenerative processes both on the tissue scale, where adequate resistance to mechanical stress is required, as well as at the cellular level where compliant chemical–physical and mechanical properties can promote cellular activity. In this study, based on a previous optimization study of this group, the potential of a three-dimensional construct based on polycaprolactone (PCL) and a novel biocompatible Mg- and Sr-containing glass named BGMS10 was explored. Fourier-transform infrared spectroscopy and scanning electron microscopy showed the inclusion of BGMS10 in the scaffold structure. Mesenchymal stem cells cultured on both PCL and PCL-BGMS10 showed similar tendencies in terms of osteogenic differentiation; however, no significant differences were found between the two scaffold types. This circumstance can be explained via X-ray microtomography and atomic force microscopy analyses, which correlated the spatial distribution of the BGMS10 within the bulk with the elastic properties and topography at the cell scale. In conclusion, our study highlights the importance of multidisciplinary approaches to understand the relationship between design parameters, material properties, and cellular response in polymer composites, which is crucial for the development and design of scaffolds for bone regeneration.

Mechanical heterogeneity in a soft biomaterial niche controls BMP2 signaling

The extracellular matrix is known to impact cell function during regeneration by modulating growth factor signaling. However, how the mechanical properties and structure of biomaterials can be used to optimize the cellular response to growth factors is widely neglected. Here, we engineered a macroporous biomaterial to study cellular signaling in environments that mimic the mechanical stiffness but also the mechanical heterogeneity of native extracellular matrix. We found that the mechanical interaction of cells with the heterogeneous and non-linear deformation properties of soft matrices (E<5kPa) enhances BMP-2 growth factor signaling with high relevance for tissue regeneration. In contrast, this effect is absent in homogeneous hydrogels that are often used to study cell responses to mechanical cues. Live cell imaging and in silico finite element modeling further revealed that a subpopulation of highly active, fast migrating cells is responsible for most of the material deformation, while a second, less active population experiences this deformation as an extrinsic mechanical stimulation. At an overall low cell density, the active cell population dominates the process, suggesting that it plays a particularly important role in early tissue healing scenarios where cells invade tissue defects or implanted biomaterials.Taken together, our findings demonstrate that the mechanical heterogeneity of the natural extracellular matrix environment plays an important role in triggering regeneration by endogenously acting growth factors. This suggests the inclusion of such mechanical complexity as a design parameter in future biomaterials, in addition to established parameters such as mechanical stiffness and stress relaxation.

Morphomechanics: An Extended View

Morphomechanics is based on the idea that living matter can mechanically self-organize into forms without the need for a pre-pattern, as recently supported by the physics of active matter. Here an extended view is proposed that integrates bioelectricity and differentiation waves as the mechanisms by which cells measure mechanical stress and couple morphogenesis and cell differentiation, respectively. Morphomechanics is a largely unexplored approach, which however could deeply transform our way of seeing nature.

Assessing the Stress Induced by Novel Packaging in GaN HEMT Devices via Raman Spectroscopy

Micro-Raman spectroscopy was carried out to evaluate the localized residual stresses in commercial Gallium-Nitride-based devices, specifically, AlGaN/GaN high-electron-mobility Transistors (HEMTs) with a novel packaging design provided by STMicroelectronics S.r.l. (Catania, Italy). The packaging plays a key role in protecting the device core against the external environment, thus minimizing damages caused by mechanical shocks, exposure to light, and contact with chemicals, conjointly achieving an efficient heat dissipation rate. Even though the packaging is a required step for the proper functioning of ready-to-use electronic devices, its application typically may introduce mechanical stress to AlGaN/GaN HEMTs, which can result in various reliability issues. In this paper, we investigate the impact of packaging on residual stress by analyzing the frequency shift of the E2 Raman peak along GaN layers and at the GaN/Si interface. An extensive evaluation was conducted using both a packaged device and a wafer-level device. The correlation between Raman frequency shifts of the E2 mode was accurately quantified, revealing a stress mitigation of approximately 0.1 GPa. This reduction is ascribed to the compressive stress introduced by the packaging, which partially offsets the intrinsic tensile stress of the wafer-level device. The proposed methodology could, in principle, be implemented to improve the development of packaging.

Exposure assessment and risks associated with wearing silver nanoparticle-coated textiles

Background Silver (Ag) nanoparticles (NPs) are used increasingly in consumer and healthcare fabrics due to their antimicrobial properties. Abrasive leaching experiments have shown that AgNPs can be released during textile wear and cause a dermal exposure. Derived-no-effect-limit value for AgNPs ranges from 0.01 to 0.0375 mg/kg-body-weight, and thus, low exposures levels can cause relevant risk. Methods In this study AgNP release from textiles by artificial sweat immersion and mechanical stress was investigated. A mass balance model was used to calculate dermal Ag exposure and potential intake via percutaneous absorption and inadvertent (peri-)oral intake during wear of face mask, suit with a full body exposure and gloves. Mass flow analysis was performed for up to 8-h wear time and by using Ag penetration rate constants reported for fresh-, cryopreserved- and glycerolized skin grafts. Results Dermal intake risk characterization ratio (RCR) during 8-h wear time for glycerolized skin was up to 0.02 for face mask and 0.9 for full body wear in a worst-case condition. Wearing gloves for 1-h followed by single unintentional fingertip mouthing (contact area 11.5 cm2) resulted in an RCR of 0.0002. RCR varied depending on the type of textile-product, exposure wear duration and skin type. Conclusions This study provides a comprehensive assessment of AgNPs release from textiles and their potential impact on human dermal exposure and was essential for understanding the safety implications for different exposure scenarios and mitigating potential risks.

Design Principle and Development Trends of Silicon-Based Anode Binders for Lithium-ion Batteries: A Mini Review

Abstract: Silicon (Si), recognized as a promising alternative material for the anodes of lithium-ion batteries, boasts a high theoretical specific capacity and abundant natural availability. During the preparation of silicon-based anodes, binders play a pivotal role in ensuring the cohesion of silicon particles, conductive agents, and current collectors. The structure and performance of these binders are critical for the mechanical stability, electrical conductivity, and stress dissipation capacity of the anodes. This review initially outlines the structural characteristics of various binders, including linear, branched, and three-dimensional cross-linked types. It then delves into the relationship between the structure and properties of these binders in the context of their application in high-performance lithium-ion batteries, focusing on their mechanical properties, electrical conductivity, and self-healing capabilities. Particular attention is given to the design strategies for binders that facilitate stress dissipation, with an emphasis on integrating multifunctional polymer binders renowned for their superior conductive and self-healing features. Such binders contribute to the formation of a robust three-dimensional network structure via multiple bonding mechanisms, including chemical, non-covalent, and coordination interactions. This configuration significantly enhances the adhesion between silicon particles, thereby facilitating the efficient dissipation of stress, which is a key aspect for ensuring the long-term cycling stability of lithium-ion batteries. Lastly, the paper explores future development directions for silicon anode binders, advocating for a thorough investigation into the synergy of diverse structural and functional combinations, with the aim of advancing the performance and practical application of silicon-based lithium-ion batteries.

Facile and efficient fabrication of carbon nanotube reinforced epoxy vitrimers through dynamic crosslinking

AbstractCarbon nanotubes (CNT) is an ideal candidate for reinforced epoxy vitrimer composites, however, achieving a desirable improvement of the mechanical properties is a great challenge owing to CNT is extremely easy to aggregate. In this study, well‐dispersed CNT reinforced epoxy vitrimers, namely EVD/CNT, were prepared by combining ultrasonic dispersion and dynamic crosslinking techniques, using multiple wall carbon nanotube as reinforcement filler, sebacic acid as curing agent, diglycidyl ether of bisphenol A (DGEBA) as epoxy monomer, zinc acetylacetonate as transesterification catalyst, torque rheometer (internal mixer) as dynamic crosslinking equipment. The CNT reinforced epoxy vitrimers, namely EVS/CNT, were prepared using traditional static curing method. The structure and morphology, mechanical properties and stress relaxation behavior of EVS/CNT and EVD/CNT were comparatively investigated, and the influence of CNT content on the structure and properties of EVD/CNT prepared by dynamic crosslinking method were also studied. The results indicated that dynamic crosslinking technology can stably disperse CNT into epoxy vitrimer resin matrix under continuous shear force. However, CNT experienced severe secondary agglomeration during the static curing process. When the loading amount of CNT was 2 wt%, the tensile strength and elongation at break of EVD/CNT‐2 were 3.2 times and 2.2 times higher than those of EVS/CNT‐2, respectively. The Young's modulus and glass transition temperature (Tg) of EVD/CNT‐2 (6.43 ± 1.10 MPa, 29.6°C) were also higher than those of EVS/CNT‐2 (5.46 ± 0.31 MPa, 25.4°C). Moreover, dynamic crosslinking technology greatly shortened the reaction time of CNT reinforced epoxy vitrimers, improved production efficiency and reduced reaction energy consumption, and was expected to be used for large‐scale and industrial production.

Hippo-PKCζ-NFκB signaling axis: A druggable modulator of chondrocytes responses to mechanical stress

Hippo-PKCζ-NFκB signaling axis: A druggable modulator of chondrocytes responses to mechanical stress

Analysis of different wave characteristics in a fiber-reinforced thermo-piezoelectric rotating medium influenced by gravity

Fiber-reinforced polymer composites possess a lightweight nature, corrosion resistance, high strength, and specific stiffness. As a result, they play a crucial role in the construction and rehabilitation of structures, providing reinforcement with their versatile and beneficial properties. Owing to this, proposed mathematical model is intended to give a detailed analysis of the characteristics of surface waves in a homogeneous, transversely isotropic fiber-reinforced thermo-piezoelectric (FRTPC) composite half-space rotating with uniform angular frequency including Coriolis and centrifugal forces. Recently proposed Moore–Gibson–Thompson thermoelasticity theory with two-temperature is employed to describe the mathematical framework. The free surface is considered to be stress free, electrically shorted/charge free, and thermally insulated/isothermal. The FRTPC structure is analytically modeled by the Strength of Materials technique with the Rule of Mixtures approach. Normal mode technique is used to derive the expression for mechanical stresses, electrical displacement, and temperature gradient. Depending upon four different boundary conditions, corresponding secular equations are derived for the considered half-space. The influence of rotation, gravity, fiber volume fraction, and two-temperature on different wave characteristics (phase velocity, attenuation coefficient, specific loss, and frequency shift) is demonstrated graphically considering PZT-5H epoxy material. Numerical simulation indicates that wave propagates at a finite speed in the FRTPC medium in the case of MGT thermoelastic theory, rather than the infinite speed in the classical thermoelasticity model. The present mathematical study may find its application in designing of gyroscopes, rotation sensors, temperature sensors, and other pyro/piezoelectric surface acoustic wave devices.

Multifocal Osteonecrosis in Spinal Cord Injury

Dear Editors, Necrosis of the bone marrow and trabecular portion as a result of limited blood flow is known as osteonecrosis (ON) [1]. Several causes have been proposed for the development of ON, including vascular occlusions, ischemia, intravascular coagulation in interosseous tissue, increased intracortical pressure, mechanical stress, precursor cell death, and suppression of angiogenesis. There are multiple risk factors and medical condition associated with ON, including infections, hematological and coagulation problems, connective tissue illnesses, kidney diseases, excessive alcohol and tobacco use, and the use of corticosteroids and cytotoxic drugs [2]. Multifocal osteonecrosis, defined as the presence of osteonecrosis in three or more bone sites, is a rare entity representing less than 3% of osteonecrosis patients [3]. Due to its potent anti-inflammatory properties, methyl prednisolone (MP), one of the most extensively used corticosteroids, has been used for a long time in the acute phase of spinal cord injury and brain edema due to its strong anti-inflammatory properties [4]. Although studies have reported cases of multifocal osteonecrosis (MFON) brought on by corticosteroid medication, this link has never been examined in a patient with a spinal cord injury. This letter aims to highlight MFON that occurred in a patient who underwent acute spinal cord injury and high-dose steroid therapy.

Spatiotemporal Characterization of Microstructure Morphology, Mechanical Properties and Bone Remodeling of Rat Tibia Under Uniaxial Compressive Overload Loading.

Bone tissue is subjected to increased mechanical stress during high-intensity work. Inadequate bone remodeling reparability can result in the continuous accumulation of microdamage, leading to stress fractures. The aim of this work was to investigate the characteristics and repair mechanisms of tibial microdamage under several degrees of overload. Also, we aimed at better understanding the effects of overload on the multi-scale structure and mechanical properties of bone. Sixty 5-month female rats were divided into three groups with different time points. Micro-CT was used to evaluate the three-dimensional microstructure, and three-point bending, quasi-static fracture toughness and creep mechanical test were carried out to evaluate the mechanical properties. SEM was used to observe the morphological characteristics of fracture surfaces. Section staining was used to count the microdamage parameters and numbers of osteoblasts and osteoclasts. The microarchitectures of cancellous and cortical bones in the three overload groups showed different degrees of damage. Overload led to a messy crystal structure of cortical bone, with slender microcracks mixed in, and a large number of broken fibers of cancellous bone. The properties associated with the elastic plasticity, fracture toughness, and viscoelasticity of cortical bone reduced in three groups, with that corresponding to day 30 presenting the highest damage. The accumulation of microdamage mainly occurred in the first 14days, that is, the crack density peaked on day 14. Peak-targeted bone remodeling of cortical and cancellous bones occurred mainly between days 14 and 30. The influence of overload mechanical environment on bone quality at different time points was deeply investigated, which is of great significance for the etiology and treatment of stress fractures.

Biomechanical impact of different isthmus positions in mandibular first molar root canals: a finite element analysis.

This study used image-based finite element analysis (FEA) to assess the biomechanical changes in mandibular first molars resulting from alterations in the position of the root canal isthmus. A healthy mandibular first molar, characterized by two intact root canals and a cavity-free surface, was selected as the subject. A three-dimensional model for the molar was established using scanned images of the patient's mandibular teeth. Subsequently, four distinct finite element models were created, each representing varied root canal morphologies: non-isthmus (Group A), isthmus located at the upper 1/3 of the root (Group B), middle 1/3 of the root (Group C), and lower 1/3 of the root (Group D). A static load of 200 N was applied along the tooth's longitudinal axis on the occlusal surface to simulate regular chewing forces. The biomechanical assessment was conducted regarding the mechanical stress profile within the root dentin. The equivalent stress (Von Mises stress) was used to assess the biomechanical features of mandibular teeth under mechanical loading. In Group A (without an isthmus), the maximum stress was 22.2MPa, while experimental groups with an isthmus exhibited higher stresses, reaching up to 29.4MPa. All maximum stresses were concentrated near the apical foramen. The presence of the isthmus modified the stress distribution in the dentin wall of the tooth canal. Notably, dentin stresses at specific locations demonstrated differences: at 8mm from the root tip, Group B: 13.6MPa vs. Group A: 11.4MPa; at 3mm from the root tip, Group C: 14.2MPa vs. Group A: 4.5MPa; at 1mm from the root tip, Group D: 25.1MPa vs. Group A: 10.3MPa. The maximum stress in the root canal dentin within the isthmus region was located either at the top or bottom of the isthmus. A root canal isthmus modifies the stress profile within the dentin. The maximum stress occurs near the apical foramen and significantly increases when the isthmus is located closer to the apical foramina.