Incidence and prognostic factors of residual back pain in patients treated for osteoporotic vertebral compression fractures: a systematic review and meta-analysis.

BACKGROUND: Osteoporotic vertebral compression fracture (OVCF) is a common consequence of osteoporosis and can significantly impact the quality of life for affected individuals. Despite treatment options such as vertebroplasty and kyphoplasty, many patients continue to experience residual back pain (RBP) even after the fracture has healed. The incidence of RBP after OVCF treatment varies among studies, and there is a need for further research to understand the risk factors associated with RBP. METHODS: A systematic review and meta-analysis were conducted following the PRISMA guidelines. Electronic databases were searched, and relevant studies were selected based on inclusion and exclusion criteria. Data extraction and quality assessment were performed independently by two authors. Statistical analysis included single-proportion meta-analyses and pooling of odds ratios (OR) using the inverse-variance method, to calculate the overall incidences of RBP and cement leakage and identify risk factors associated with RBP. RESULTS: A total of 19 studies were included in the analysis. The overall incidences of RBP and cement leakage were found to be 16% and 18%, respectively. Several risk factors were identified, including gender, bone mineral density, depression, baseline visual analog scale (VAS) score, intravertebral vacuum cleft, number of fractured segments, cement distribution, history of vertebral fracture, thoracolumbar fascial injury, and fracture non-union. CONCLUSIONS: This study provides potential value within the scope of the incidence and risk factors of RBP following treatment of OVCFs. The identified risk factors can help clinicians identify high-risk patients and tailor appropriate interventions. Future research should focus on standardizing the definition of RBP and patient selection criteria to improve the accuracy of estimates and facilitate better management strategies for OVCF patients.

Application of Electrophysiological Techniques in Assessing of Neuromuscular Junction-Related Disorders.

This review aims to comprehensively summarize the application of electrophysiological methods, specifically repetitive nerve stimulation (RNS) and single fiber electromyography (SFEMG), in the diagnosis of neuromuscular junction (NMJ) disorders, including myasthenia gravis, Lambert-Eaton syndrome, and sarcopenia in the elderly. Both RNS and SFEMG have demonstrated high sensitivity and specificity in detecting NMJ abnormalities. RNS aids in distinguishing presynaptic from postsynaptic lesions, while SFEMG provides direct evidence of NMJ function by assessing single motor unit action potentials. Key parameters in SFEMG, such as fiber density, jitter, and pulse blocking, are crucial for evaluating NMJ function. Increased fiber density and jitter value, along with pulse blocking, are often observed in patients with NMJ disorders. However, despite the extensive application of these techniques in various NMJ-related diseases, their role in aging, particularly in sarcopenic patients, remains underexplored, highlighting the need for future research.

Rapid Construction of Polycyclic Skeletons via Brønsted-Base-Catalyzed Annulations of Ethylidene 1,3-Indenediones and Vinyl 1,2-Diketones.

Brønsted-base-catalyzed diversified annulations between ethylidene 1,3-indenediones and vinyl 1,2-diketones have been achieved, delivering three types of products containing oxabicyclo[3.2.1]octane, spiro[4.5]decane, and branched triquinane skeletons, respectively, which widely exist in natural products and bioactive substances. Two unprecedented reaction modes have been disclosed, and the reactions could be readily scaled up. The protocol shows the potential of 1,2-diketone-mediated reactions in the rapid construction of complicated polycyclic scaffolds.

Regio- and Stereoselective Transfer Hydrogenation of Aryloxy Group-Substituted Unsymmetrical 1,2-Diketones: Synthetic Applications and Mechanistic Studies.

Developing a general method that leads to the formation of different classes of chiral bioactive compounds and their stereoisomers is an attractive but challenging research topic in organic synthesis. Furthermore, despite the great value of asymmetric transfer hydrogenation (ATH) in both organic synthesis and the pharmaceutical industry, the monohydrogenation of unsymmetrical 1,2-diketones remains underdeveloped. Here, we report the aryloxy group-assisted highly regio-, diastereo-, and enantioselective ATH of racemic 1,2-diketones. The work produces a myriad of enantioenriched dihydroxy ketones, and further transformations furnish all eight stereoisomers of diaryl triols, polyphenol, emblirol, and glycerol-type natural products. Mechanistic studies and calculations reveal two working modes of the aryloxy group in switching the regioselectivity from a more reactive carbonyl to a less reactive one, and the potential of ATH on 1,2-diketones in solving challenging synthetic issues has been clearly demonstrated.

Gypenoside L inhibits hepatocellular carcinoma by targeting the SREBP2-HMGCS1 axis and enhancing immune response.

Hepatocellular carcinoma (HCC) is a malignant tumor that occurs in the liver, with a high degree of malignancy and relatively poor prognosis. Gypenoside L has inhibitory effects on liver cancer cells. However, its mechanism of action is still unclear. This study aims to investigate the inhibitory effects of gypenoside L on HCC in vitro and in vivo, and explore its potential mechanisms. The results showed that gypenoside L reduced the cholesterol and triglyceride content in HepG2 and Huh-7 cells, inhibited cell proliferation, invasion and metastasis, arrested cell cycle at G0/G1 phase, promoted cell apoptosis. Mechanistically, it targeted the transcription factor SREPB2 to inhibit the expression of HMGCS1 protein and inhibited the downstream proteins HMGCR and MVK, thereby regulating the mevalonate (MVA) pathway. Overexpression HMGCS1 led to significant alterations in the cholesterol metabolism pathway of HCC, which mediated HCC cell proliferation and conferred resistance to the therapeutic effect of gypenoside L. In vivo, gypenoside L effectively suppressed HCC growth in tumor-bearing mice by reducing cholesterol production, exhibiting favorable safety profiles and minimal toxic side effects. Gypenoside L modulated cholesterol homeostasis, enhanced expression of inflammatory factors by regulating MHC I pathway-related proteins to augment anticancer immune responses. Clinical samples from HCC patients also exhibited high expression levels of MVA pathway-related genes in tumor tissues. These findings highlight gypenoside L as a promising agent for targeting cholesterol metabolism in HCC while emphasizing the effectiveness of regulating the SREBP2-HMGCS1 axis as a therapeutic strategy.

Catalytic Asymmetric Transfer Hydrogenation of Acylboronates: BMIDA as the Privileged Directing Group.

Developing a general, highly efficient, and enantioselective catalytic method for the synthesis of chiral alcohols is still a formidable challenge. We report in this article the asymmetric transfer hydrogenation (ATH) of N-methyliminodiacetyl (MIDA) acylboronates as a general substrate-independent entry to enantioenriched secondary alcohols. ATH of acyl-MIDA-boronates with (het)aryl, alkyl, alkynyl, alkenyl, and carbonyl substituents delivers a variety of enantioenriched α-boryl alcohols. The latter are used in a range of stereospecific transformations based on the boron moiety, enabling the synthesis of carbinols with two closely related α-substituents, which cannot be obtained with high enantioselectivities using direct asymmetric hydrogenation methods, such as the (R)-cloperastine intermediate. Computational studies illustrate that the BMIDA group is a privileged enantioselectivity-directing group in Noyori-Ikariya ATH compared to the conventionally used aryl and alkynyl groups due to the favorable CH-O attractive electrostatic interaction between the η6-arene-CH of the catalyst and the σ-bonded oxygen atoms in BMIDA. The work expands the domain of conventional ATH and shows its huge potential in addressing challenges in symmetric synthesis.

Clinical application of digital technology in the use of anterolateral thigh lobulated perforator flaps to repair complex soft tissue defects of the limbs.

Background: It is challenging to repair wide or irregular defects with traditional skin flaps, and anterolateral thigh (ALT) lobulated perforator flaps are an ideal choice for such defects. However, there are many variations in perforators, so good preoperative planning is very important. This study attempted to explore the feasibility and clinical effect of digital technology in the use of ALT lobulated perforator flaps for repairing complex soft tissue defects in limbs. Methods: Computed tomography angiography (CTA) was performed on 28 patients with complex soft tissue defects of the limbs, and the CTA data were imported into Mimics 20.0 software in DICOM format. According to the perforation condition of the lateral circumflex femoral artery and the size of the limb defect, one thigh that had two or more perforators from the same source vessel was selected for 3D reconstruction of the ALT lobulated perforator flap model. Mimics 20.0 software was used to visualize the vascular anatomy, virtual design and harvest of the flap before surgery. The intraoperative design and excision of the ALT lobulated perforator flap were guided by the preoperative digital design, and the actual anatomical observations and measurements were recorded. Results: Digital reconstruction was successfully performed in all patients before surgery; this reconstruction dynamically displayed the anatomical structure of the flap vasculature and accurately guided the design and harvest of the flap during surgery. The parameters of the harvested flaps were consistent with the preoperative parameters. Postoperative complications occurred in 7 patients, but all flaps survived uneventfully. All of the donor sites were closed directly. All patients were followed up for 13-27 months (mean, 19.75 months). The color and texture of each flap were satisfactory and each donor site exhibited a linear scar. Conclusions: Digital technology can effectively and precisely assist in the design and harvest of ALT lobulated perforator flaps, provide an effective approach for individualized evaluation and flap design and reduce the risk and difficulty of surgery.

The biomechanical effects of bimaxillary osteotomies to the patients with mandibular retraction under incisal clenching.

The purpose of this study is to investigate the biomechanical effect of bimaxillary osteotomies on patients with mandibular retraction. Mandibular retraction, as a typical maxillofacial deformity, and has great adverse effects on TMJ. Bimaxillary osteotomies are widely used to correct symptoms of mandibular retraction. It is necessary to understand the effect of surgery on temporomandibular disc (TMJ). Five patients with mandibular retraction and 10 asymptomatic subjects were involved in this study. Finite element models of preoperative, postoperative and control group were constructed based on the CT data. Nine sets of concentrated forces were used to simulate the muscle effect and contact method was used to simulate the interaction within the TMJs and dentitions. The results showed that bimaxillary osteotomies could effectively improve the maxillofacial morphology and alleviate the overload in TMJ. The facial asymmetry and right chewing side preference could cause imbalanced stress distributions in the TMJs and interfere the surgical treatment.

The biomechanical effects of bilateral sagittal split ramus osteotomy and bimaxillary osteotomies to the patients with maxillofacial deformities under incisal clenching.

OBJECTIVE: Bilateral sagittal split ramus osteotomy (BSSRO) and bimaxillary osteotomies (BSSRO plus Lefort1 osteotomy) are widely used to solve maxillofacial deformities. The effect of the surgeries on the temporomandibular joint (TMJ) is still not clear. The purpose of this study was to investigate the preoperative and postoperative stress environment of the patients and to compare the biomechanical differences of the two surgeries. METHODS: Ten patients were performed BSSRO and fourteen underwent bimaxillary osteotomies. Eleven asymptomatic subjects were recruited to be the control group. The muscle forces of incisal clenching were applied on the finite element models. And contact was used to simulate the interactions within the TMJs. RESULTS: two kinds of surgeries could not completely eliminate the negative biomechanical distribution within the TMJs. CONCLUSION: Compared to BSSRO only, the bimaxillary osteotomies could better repair the biomechanical environment of the TMJs under incisal clenching. And the TMD symptoms were strongly related to the stress distributions of the TMJs.

Digital anatomical study and clinical application of the ideal S2 alar-lliac screw trajectory.

BACKGROUND: To investigate the ideal trajectory for the S2AI screw and to clinically validate its safety feasibility. METHODS: The 3D model was reconstructed from CT data of the pelvis of 30 selected adults, and the 3D coordinate system was established with the first sacral superior endplate as the horizontal plane. A set of cutting planes was made at 3 mm intervals in the coronal plane, and the cross-sectional internal tangent circles were divided in the target area. Using the linear fitting function, the axis of 90 mm length was calculated by the least squares method for each inner tangent circle center. The diameter of the axis is gradually increased until the first contact with the cortex, and the cylindrical model is the ideal screw trajectory. The intersection of the axis and the dorsal cortex is the screw placement point, which is located by Horizon Distance (HD) and Vertical Distance (VD); the diameter of the screw trajectory (d) is the diameter of the cylindrical model; the direction of the screw trajectory is determined by Sagittal Angle (SA) and Transverse Angle (TA). The screw trajectory orientation is determined by Sagittal Angle (SA) and Transverse Angle (TA). Based on the ideal screw trajectory, the 3D printed surgical guide and freehand techniques were used to verify its safety feasibility, respectively. RESULTS: The screw placement points [HD (4.7 ± 1.0) mm, VD (19.7 ± 1.9) mm], screw placement directions [SA (31.3°±2.3°), TA (42.4°±2.3°)], and screw dimensions for the ideal screw trajectory of the S2AI were combined for analysis. (L is 90 mm, d is 13.2 ± 1.4 mm). The S2AI screw superiority rate [96.6% (56/58)] and reasonable rate [100%] were higher in the guide group than in the freehand group [90.0% (63/70), 97.1% (68/70)], but the differences were not statistically significant (P > 0.05). Although screws invaded the cortex in both groups, there were no associated adverse events in either group. CONCLUSION: The S2AI screw-based ideal trajectory placement is a safe, feasible and accurate method of screw placement.

Protective effect of heat-processed Gynostemma pentaphyllum on high fat diet-induced glucose metabolic disorders mice.

Glucose metabolic disorders (GMD) can promote insulin resistance (IR) and diabetes, and damage liver and kidney. Gynostemma pentaphyllum is commonly used in the clinical treatment of diabetes, but the research on its main active constituents and GMD has not been reported yet. This study explores the therapeutic potential of gypenosides of heat-processed Gynostemma pentaphyllum (HGyp) on high-fat diet-induced GMD in mice. HGyp was administered at different doses for 12 weeks. The investigation encompassed an array of parameters, including body weight, blood lipids, blood glucose, and liver tissue components. Metabolomic and network analyses were conducted to uncover potential targets and pathways associated with HGyp treatment. The results revealed that HGyp alleviated GMD by reducing body weight, blood glucose, and improving blood lipids levels, while increasing liver glycogen and antioxidant enzyme levels. Additionally, HGyp exhibited protective effects on liver and kidney health by reducing tissue damage. Fourteen blood components were detected by LC-MS. Metabolomic and network analyses indicated the potential engagement of the AGE-RAGE signaling pathway in the therapeutic effects of HGyp.Furthermore, Western blot and ELISA assays confirmed that HGyp upregulated GLO1 and GLUT4 while down-regulating AGEs and RAGE expression in liver tissue. In light of these findings, HGyp demonstrates promise as a potential therapeutic candidate for combating GMD, warranting further exploration in the development of therapeutic strategies or functional products.

Aging-related decrease of histone methyltransferase SUV39H1 in adipose-derived stem cells enhanced SASP.

Aging-related diseases are closely associated with the state of inflammation, which is known as "inflammaging." Senescent cells are metabolically active, as exemplified by the secretion of inflammatory cytokines, chemokines, and growth factors, which is termed the senescence-associated secretory phenotype (SASP). Epigenetic regulation, especially the structural regulation of chromatin, is closely linked to the regulation of SASP. In our previous study, the suppressor of variegation 3-9 homolog 1 (SUV39H1) was elucidated to interact with Lhx8 and determine the cell fate of mesenchyme stem cells. However, the function of SUV39H1 during aging and the underlying mechanism of its epigenetic regulation remains controversial. Therefore, the C57BL/6 J CAG-Cre; SUV39H1fl/fl knockout mice and irradiation-induced cellular senescence model were built in this study to deepen the understanding of epigenetic regulation by SUV39H1 and its relation to SASP. In vivo and in vitro studies demonstrated that SUV39H1 decreased with aging and served as an inhibitor of SASP, especially IL-6, MCP-1, and Vcam-1, by altering H3K9me3 enrichment in their promoter region. These results provide new insights into the epigenetic regulation of SASP.

Gypenosides suppress hepatocellular carcinoma cells by blocking cholesterol biosynthesis through inhibition of MVA pathway enzyme HMGCS1.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high morbidity and mortality. Targeting abnormal cholesterol metabolism is a potential therapeutic direction. Therefore, more natural drugs targeting cholesterol in HCC need to be developed. Gypenosides (Gyp), the major constituent of Gynostemma pentaphyllum, has been demonstrated to have pharmacological properties on anti-cancer, anti-obesity, and hepatoprotective. We investigated whether Gyp, isolated and purified by our lab, could inhibit HCC progression by inhibiting cholesterol synthesis. The present research showed that Gyp inhibited proliferation and migration, and induced apoptosis in Huh-7 and Hep3B cells. Metabolomics, transcriptomics, and target prediction all suggested that lipid metabolism and cholesterol biosynthesis were the mechanisms of Gyp. Gyp could limit the production of cholesterol and target HMGCS1, the cholesterol synthesis-related protein. Downregulation of HMGCS1 could suppress the progression and abnormal cholesterol metabolism of HCC. In terms of mechanism, Gyp suppressed mevalonate (MVA) pathway mediated cholesterol synthesis by inhibiting HMGCS1 transcription factor SREBP2. And the high expression of HMGCS1 in HCC human specimens was correlated with poor clinical prognosis. The data suggested that Gyp could be a promising cholesterol-lowering drug for the prevention and treatment of HCC. And targeting SREBP2-HMGCS1 axis in MVA pathway might be an effective HCC therapeutic strategy.

2H-Phosphindole-Enabled Dearomatization and [4+2] Cycloaddition of (Hetero)Arenes.

The heavier main group multiple bonds offer an effective tool for small molecule activation. Transient 2H-phosphinidole working as a reactive phosphadiene system undergoes phospha-Diels-Alder reaction with a wide range of non-activated aromatic carbocycles and heterocycles, including naphthalene, anthracene, phenanthrene, furan, thiophene, pyrrole, pyridine, and benzo-fused heterocycles, affording concise access to a range of polycyclic fused rings feature with phosphorus at the bridgehead. These results demonstrate that non-activated (hetero)arenes are capable of acting as 2π systems in [4+2] cycloaddition with highly reactive 2H-phosphindole complex.

Genetically engineered CXCR4-modified exosomes for delivery of miR-126 mimics to macrophages alleviate periodontitis.

Biofilm-related diseases are a group of diseases that tolerate antimicrobial chemotherapies and therefore are refractory to treatment. Periodontitis, a non-device chronic biofilm disease induced by dental plaque, can serve as an excellent in vivo model to study the important effects of host factors on the biofilm microenvironment. Macrophage activity is one of the key factors that modulate the progression of inflammation-driven destruction in periodontitis; therefore it is an important host immunomodulatory factor. In this study, the reduction of microRNA-126 (miR-126) with the recruitment of macrophages in periodontitis was confirmed in clinical samples, and a strategy for targeted delivery of miR-126 to macrophages was explored. Exosomes overexpressing the C-X-C motif chemokine receptor 4 (CXCR4) loaded with miR-126 (CXCR4-miR126-Exo) was successfully constructed, which reduced off-target delivery to macrophages and regulated macrophages toward the anti-inflammatory phenotype. In vivo local injection of CXCR4-miR126-Exo into sites of periodontitis in rats effectively reduced bone resorption and osteoclastogenesis and inhibited the progression of periodontitis. These results provide new insights for designing novel immunomodulatory factor targeted delivery systems to treat periodontitis and other biofilm-related diseases.

Effects of bilateral sagittal split ramus osteotomy and bimaxillary osteotomies on stress distribution of temporomandibular joints in patients with maxillofacial deformity under asymmetric occlusions.

Bilateral sagittal split ramus osteotomy (BSSRO) and bimaxillary osteotomies (BSSRO plus Lefort1 osteotomy) are representative surgeries to solve maxillofacial deformity. It is important to understand the biomechanical impact of the surgeries on the temporomandibular joint (TMJ). The purpose of this study is to compare the stress variations of the patients before and after the two surgeries. Twenty-four patients with maxillofacial deformities and 14 asymptomatic subjects were recruited to be the preoperative group and control group in this study. Ten patients were performed BSSRO and other 14 underwent bimaxillary osteotomies. Finite element models of the preoperative, postoperative, and control groups were established according to the CBCT data of the subjects. The muscle forces of the left and right unilateral occlusion were applied on the models. And the contact was used to simulate the interaction within the TMJs and between the maxillary and mandibular teeth. Under the asymmetric occlusion, bimaxillary osteotomies were found to be superior to BSSRO in the stress distributions of the TMJs. The magnitude of the asymmetric stresses was strongly correlated with the TMD symptoms in the patients. And the stress variation of the postoperative TMJs was the cause of the improvement or aggravation of the TMD symptoms.

Dearomatization [4+2] Cycloaddition of Nonactivated Benzene Derivatives.

Dearomatization reactions have recently emerged as a powerful tool for the rapid buildup of molecular complexity. Here, an unparalleled thermal dearomatization [4+2] cycloaddition reaction between benzene derivatives and a 2H-phosphindole tungsten complex was reported. The unique reactivity of the in situ-generated 2H-phosphindole complex toward benzene was revealed by density functional theory calculations. We thus provide new insights into the dearomatization of nonactivated arenes and pave the way for the manipulation of the dearomatization for further applications.

Synergistic osteogenic and angiogenic effects of KP and QK peptides incorporated with an injectable and self-healing hydrogel for efficient bone regeneration.

Irregular defects generated by trauma or surgery in orthopaedics practice were usually difficult to be fitted by the preformed traditional bone graft substitute. Therefore, the injectable hydrogels have attracted an increasing interest for bone repair because of their fittability and mini-invasivity. However, the uncontrollable spreading or mechanical failures during its manipulation remain a problem to be solved. Moreover, in order to achieve vascularized bone regeneration, alternatives of osteogenic and angiogenic growth factors should be adopted to avoid the problem of immunogenicity and high cost. In this study, a novel injectable self-healing hydrogel system (GMO hydrogel) loaded with KP and QK peptides had been developed for enhancing vascularized regeneration of small irregular bone defect. The dynamic imine bonds between gelatin methacryloyl and oxidized dextran provided the GMO hydrogel with self-healing and shear-thinning abilities, which led to an excellent injectability and fittability. By photopolymerization of the enclosed GelMA, GMO hydrogel was further strengthened and thus more suitable for bone regeneration. Besides, the osteogenic peptide KP and angiogenic peptide QK were tethered to GMO hydrogel by Schiff base reaction, leading to desired releasing profiles. In vitro, this composite hydrogel could significantly improve the osteogenic differentiation of BMSCs and angiogenesis ability of HUVECs. In vivo, KP and QK in the GMO hydrogel demonstrated a significant synergistic effect in promoting new bone formation in rat calvaria. Overall, the KP and QK loaded GMO hydrogel was injectable and self-healing, which can be served as an efficient approach for vascularized bone regeneration via a minimally invasive approach.

Nanosized FeS/ZnS heterojunctions derived using zeolitic imidazolate Framework-8 (ZIF-8) for pH-universal oxygen reduction and High-efficiency Zn-air battery.

Low-cost, stable, and highly active electrocatalysts for oxygen reduction reaction (ORR), especially for pH-universal ORR, are vital for developing numerous renewable energy devices. Herein, a hierarchical N, S-codoped porous carbon-based catalyst (ZFP-800) coupled with abundant FeS/ZnS heterojunctions was facilely prepared via direct pyrolysis of a Ferrocene-crosslinked pyrrole hydrogel composited with zeolitic imidazolate framework-8 (ZIF-8) templates. Compared with the heterojunction-free catalytic activity, the ZFP-800 catalytic activity was significantly higher in pH-universal ranges. Moreover, the ZFP-800 exhibited competitive ORR performance to commercial Pt/C (20%) in various electrolytes, in terms of onset (Eonset), half-wave potentials (E1/2), limiting current density (JL), durability, and methanol immunity. For instance, it exhibited super ORR catalytic activity on Eonset and E1/2, and exceeded that of the benchmark Pt/C in both the alkaline and neutral media. Furthermore, the application of ZFP-800 as a cathode catalyst in a home-made Zn-air battery demonstrated its operation capability in ambient conditions with a competitive performance on the specific energy density (828 mA·h·gZn-1), maximum discharge power density (205.6 mW·cm-2), rate performance, and the long-term stability (188 h at 5 mA·cm-2). This study can facilitate the development of advanced heterojunction-based materials for renewable energy applications.

Biomechanical effects of high acceleration on the temporomandibular joint.

The symptoms of temporomandibular disorders (TMD) are easily developed in pilots after long flights, such as joint pain, anterior displacement disc and so on. Related studies have suggested that abnormal high acceleration would cause temporomandibular joint (TMJ) lesions. Therefore, the purpose of this study is to analyze the biomechanical effects of high acceleration on the TMJs. The 3D models of the maxilla, mandible, articular disc were generated by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) of a healthy volunteer without any TMD symptoms. Then, the loads were added according to the various operating conditions of the aircraft. The maximum tensile stress, occurred in the anterior band of the discs, exceeded the failure stress. Compared with the low acceleration, the contact stresses between the discs and the articular cartilages were much greater under the high acceleration. High acceleration had a negative impact on the stress distributions of the articular discs and cartilages and easily led to TMJ damage. Lateral acceleration will cause asymmetric stress distribution of the TMJs.