共查询到20条相似文献,搜索用时 15 毫秒
1.
The effect of collagen reinforcement in the behaviour of the temporomandibular joint disc 总被引:5,自引:0,他引:5
In this paper, the influence of collagen fibres in the behaviour of the temporomandibular joint disc is studied. A three-dimensional finite element model of the joint is developed from a set of medical images. The model comprises the mandible, part of the cranium and both temporomandibular joints. Joints have been considered to be composed of the articular discs and the temporomandibular ligaments. A fibre-reinforced porohyperelastic model was used to study the response under clenching of the fibrocartilage that composes the articular disc. This was divided in an intermediate zone, and two bands, an anterior and other posterior, in order to define the orientation of collagen fibres. The study demonstrates that the introduction of collagen fibres in the biphasic behaviour of the articular disc implies for a prescribed displacement not only an increase of the pressurization in the tissue, but also higher stresses in the anterior and posterior bands, as well as in the lateral zone of the disc. Thus, modelling the disc as an isotropic solid matrix leads in this case to an overestimation of the stresses in the intermediate zone, an underestimation of the pore pressure in this area, and an underestimation of the stresses in the rest of the disc. 相似文献
2.
Zhan Liu Jingheng Shu Yuanli Zhang 《Computer methods in biomechanics and biomedical engineering》2013,16(11):617-624
AbstractThe aim of this study was to evaluate the stress distributions and deformations of the temporomandibular joint (TMJ) during different periods before and after sagittal split ramus osteotomy (SSRO). A three-dimensional finite element model of the mandible and TMJ was established, based on the preoperative CT of a patient with mandibular prognathism. Numerical SSRO was performed and the models of three postoperative periods were established. Contact elements were used to simulate the interaction between the articular discs and the articular cartilages. Nonlinear cable elements were used to simulate the disc attachments and the ligaments. Muscle forces and boundary conditions corresponding to the central occlusion were applied on all the models. The results showed that the stress distributions of the patient’s TMJs were not the same as those of asymptomatic subjects. The stress distributions and deformations of the disc, condylar and temporal cartilage were changed at different periods after SSRO. The biomechanical parameters of TMJ were improved after SSRO. And the postoperative results showed that appropriate functional training could help to avoid TMJ diseases. Therefore SSRO could improve the stress distributions of the TMJ and relieve the symptoms of temporomandibular disorder (TMD). 相似文献
3.
One of the essential causes of disk disorders is the pathologic change in the ligamentous attachments of the disk-condyle complex. In this paper, the response of the soft components of a human temporomandibular joint during mouth opening in healthy and two pathologic situations was studied. A three-dimensional finite element model of this joint comprising the bone components, the articular disk, and the temporomandibular ligaments was developed from a set of medical images. A fiber reinforced porohyperelastic model was used to simulate the behavior of the articular disk, taking into account the orientation of the fibers in each zone of this cartilage component. The condylar movements during jaw opening were introduced as the loading condition in the analysis. In the healthy joint, it was obtained that the highest stresses were located at the lateral part of the intermediate zone of the disk. In this case, the collateral ligaments were subject to high loads, since they are responsible of the attachment of the disk to the condyle during the movement of the mandible. Additionally, two pathologic situations were simulated: damage of the retrodiscal tissue and disruption of the lateral discal ligament. In both cases, the highest stresses moved to the posterior part of the disk since it was displaced in the anterior-medial direction. In conclusion, in the healthy joint, the highest stresses were located in the lateral zone of the disk where perforations are found most often in the clinical experience. On the other hand, the results obtained in the damaged joints suggested that the disruption of the disk attachments may cause an anterior displacement of the disk and instability of the joint. 相似文献
4.
Pathophysiology of the temporomandibular joint (TMJ) disc is central to many orofacial disorders; however, mechanical characterization of this tissue is incomplete. In this study, we identified surface-regional mechanical variations in the porcine TMJ disc under unconfined compression. The intermediate zone, posterior, anterior, lateral, and medial regions of eight TMJ discs were sectioned into inferior and superior surface samples. Surface-regional sections were then subjected to incremental stress relaxation tests. Single strain step (SSS) and final deformation (FD) viscoelastic models were fit to experimental data. Both models represented the experimental data with a high degree of accuracy (R(2)=0.93). The instantaneous modulus and relaxation modulus for the TMJ disc sections were approximately 500 kPa and 80 kPa, respectively; the coefficient of viscosity was approximately 3.5 MPa-s. Strain dependent material properties were observed across the disc's surface-regions. Regional variations in stiffness were observed in both models. The relaxation modulus was largest in the inferior-medial parts of the disc. The instantaneous modulus was largest in the posterior and anterior regions of the disc. Surface-to-surface variations were observed in the relaxation modulus for only the FD model; the inferior surface was found to be more resistant to compression than the superior surface. The results of this study imply the stiffness of the TMJ disc may change as strain is applied. Furthermore, the lateral region exhibited a lower viscosity and stiffness compared to other disc regions. Both findings may have important implications on the TMJ disc's role in jaw motion and function. 相似文献
5.
Objectives: The relationship of bony changes in the condylar surfaces in articular disc displacement without reduction in temporomandibular joint (TMJ) was investigated using diagnostic imaging. The study also evaluated whether the bony changes in the condylar surfaces limit disc and condyle motion, and produce pathological joint sounds. Materials and methods: Thirty‐seven joints in 28 patients diagnosed with degenerative bony changes in the condylar surfaces radiographically and anterior disc displacement without reduction using magnetic resonance imaging (MRI) were studied. The bony changes were assessed by radiographic examination and classified into two types: pathological bone changes (PBCs) including erosion, osteophyte formation and deformity, and adaptive bone changes (ABCs) including flattening and concavity. MRI was performed on the TMJ to examine the configuration and position of the discs. Joint sounds in the TMJ were determined using electrovibratograghy with a joint vibration analysis. Results: The articular disc motion to the condyle in the PBC group was smaller than in the ABC group irrespective of the configuration of the disc, even though there were no significant differences between the two types of bony changes in the disc position during jaw closing. The joint vibration analysis of the TMJ showed that joint sounds with a higher frequency were observed in the PBC group than in the ABC group. High energy levels needed to produce the higher frequencies (over 300 Hz) were observed only in the PBC group. 相似文献
6.
N. Kiga I. Tojyo T. Matsumoto Y. Hiraishi Y. Shinohara S. Fujita 《European journal of histochemistry : EJH》2010,54(3)
Lumican belongs to the small leucine-rich repeat proteoglycan (SLRP) gene family and has been reported to exist in the cornea, intervertebral disc and tendon. Lumican plays a significant role in the assembly and regulation of collagen fibres. The human temporomandibular joint (TMJ) disc is made up of fibrocartilage with an extracellular matrix (ECM) composed of collagen and proteoglycans. The existence and behaviour of lumican have not been studied in the human TMJ disc. Therefore, we used immunohistochemical methods to detect lumican, CD34 and vascular endothelial growth factor (VEGF) and histochemical staining with toluidine blue in 13 human TMJ specimens (10 surgically removed and 3 obtained from autopsy). In both normal and deformed discs we observed staining with toluidine blue. We found that the area of metachromasia inside the deformed disc was uneven and expression of lumican was strong in the areas negative for metachromasia. Staining of VEGF and CD34 inside the deformed disc was seen. We confirmed the expression of lumican in the human TMJ disc and showed that a large number of fibroblast-like cells existed in the area of strong lumican expression. These new findings about the behaviour of lumican suggest that it may play a key role in the generation of a new collagen network by fibroblast-like cells.Key words: TMJ disc, lumican, CD34, VEGF, immunohistochemistry, metachromasia. 相似文献
7.
8.
C. Loreto L.E. Almeida M.R. Migliore M. Caltabiano R. Leonardi 《European journal of histochemistry : EJH》2010,54(3)
To evaluate the apoptosis involvement in the angiogenesis as a self-limiting process in patients with temporomandibular joint (TMJ) degenerated disc vessels, we assessed, by immunohistochemistry, the detection of TRAIL, its death receptor DR5 and caspase 3. TRAIL, its death receptor DR5 and caspase 3 expression were studied by immunohistochemistry in 15 TMJ discs displaced without reduction and in 4 unaffected discs. These apoptosis molecules were detected in the intima and media layers of newly formed vessels affected discs. In conclusion, vessels apoptosis activation in TMJ disc with ID could be regarded as a self-limiting process that try to leads to vessel regression; in this way an inhibition of angiogenic vessels may prove a key strategy in limiting pathological angiogenesis, by cutting off blood supply to tumors, or by reducing harmful inflammation.Key words: temporomandibular joint disc, vessels, apoptosis. 相似文献
9.
Mandibular condylar cartilage plays a crucial role in temporomandibular joint (TMJ) function, which includes facilitating articulation with the TMJ disc, reducing loads on the underlying bone, and contributing to bone remodeling. To improve our understanding of the TMJ function in normal and pathological situations, accurate and validated three-dimensional (3-D) finite element models (FEMs) of the human TMJ may serve as valuable diagnostic tools as well as predictors of thresholds for tissue damage resulting from parafunctional activities and trauma. In this context, development of reliable biomechanical standards for condylar cartilage is crucial. Moreover, biomechanical characteristics of the native tissue are important design parameters for creating functional tissue-engineered replacements. Towards these goals, biomechanical characteristics of the condylar cartilage have been reviewed here, highlighting the structure–function correlations. Structurally, condylar cartilage, like the TMJ disc, exhibits zonal and topographical heterogeneity. Early structural investigations of the condylar cartilage have suggested that the tissue possesses a somewhat transversely isotropic orientation of collagen fibers in the fibrous zone. However, recent tensile and shear evaluations have reported a higher stiffness of the tissue in the anteroposterior direction than in the mediolateral direction, corresponding to an anisotropic fiber orientation comparable to the TMJ disc. In a few investigations, condylar cartilage under compression was found to be stiffer anteriorly than posteriorly. As with the TMJ disc, further compressive characterization is warranted. To draw inferences for human tissue using animal models, establishing stiffness–thickness correlations and regional evaluation of proteoglycan/glycosaminoglycan content may be essential. Efforts directed from the biomechanics community for the characterization of TMJ tissues will facilitate the development of reliable and accurate 3-D FEMs of the human TMJ. 相似文献
10.
The purpose of this study was to determine the force-time and force-displacement response of the human mandible under direct loading at the chin. Sub-fracture response of the mandible and temporomandibular joint (TMJ) were analyzed from 10 cadavers that were impacted at the chin with a 2.8-kg mass at drop heights of 300, 400 and 500 mm and a 5.2-kg mass at 500 mm. Motion of radio-opaque markers adhered to the surface of the bone was recorded at 1000 Hz by a bi-planar X-ray and converted to three-dimensional coordinates. Peak force ranged from 0.90 to 4.54 kN causing chin displacement of 1.2-4.4 mm. A bi-linear response was observed with stiffness of 475.1+/-199.8 kN/m for chin displacement resulting from loading up to 0.6 kN and 2381.6+/-495.7 kN/m for loads from 0.6 to 3.25 kN. This defines the biomechanical response of the mandible for chin motion under impact loading. The response of different segments of the mandible and TMJ are also documented. Force-time and force-displacement response corridors for the mandible can be used for finite element model and/or the development and validation of a biomechanical surrogate. 相似文献
11.
Cattaneo PM Kofod T Dalstra M Melsen B 《Computer methods in biomechanics and biomedical engineering》2005,8(3):157-165
An approach was developed to evaluate the load transfer mechanism in the temporomandibular joint (TMJ) area before, during and after mandibular ramus elongation by distraction osteogenesis (DO). In a concerted approach using computer tomography, magnetic resonance imaging (MRI), and finite element analysis, three-dimensional numerical models based on a young male patient, with a dento-facial deformity were generated. The magnitude and direction of the muscle forces acting on the mandible were assessed using both values derived from the muscles volume and cross-section as retrieved from the MRI-scan data-sets and taken from the literature. The resistance of the soft tissue envelope towards elongation during the DO-phase was also included. The finite element analyses showed that before skeletal correction by DO the load transfer was asymmetrical with high peak stresses in the affected joint. Following ramus elongation a more symmetrical loading in TMJs was predicted. The reaction forces in the TMJs during DO were low. 相似文献
12.
13.
Boaz Arzi Vincent P. Willard Daniel J. Huey Frank J. M. Verstraete Natalia Vapniarsky-Arzi Kyriacos A. Athanasiou 《European Journal of Wildlife Research》2012,58(2):451-459
The temporomandibular joint (TMJ) is a synovial articulation between the mandibular head of the condylar process of the mandible
and the mandibular fossa of the squamous temporal bone. Extensions of the fibrous capsule into the joint space form a biconcave
disc that functions as an articulating surface and divides the joint into dorsal and ventral compartments. The TMJ disc plays
a crucial role in normal functioning of the joint, and differences in cranial morphology, mastication patterns, and diet are
reflected in the material and biochemical properties of the disc. The purpose of the present case study was to compare the
regional histologic differences between two elephant genera and quantify the biochemical and biomechanical properties of the
African elephant disc. This study provides a unique insight into the elephant TMJ disc and also provides a comparison between
the African and the Asian elephant genera. The results demonstrate several remarkable findings. First, structure–function
relationships exist within the elephant TMJ disc. Second, regional variations exist in the elephant TMJ disc, and these are
likely to correlate with its functional requirement. Additionally, it is apparent that some properties of the disc vary with
the specific anatomy, diet requirement, and jaw motion. Finally, in comparison with the TMJ disc of other species, it is clear
that, although the elephant disc is unique, it has properties that transcend and are preserved among the species. 相似文献
14.
In this study, shear relaxation properties of the porcine temporomandibular joint (TMJ) disc are investigated. Previous studies have shown that, in fatigue failure and damage of cartilage and fibrocartilage, shear loads could be one of the biggest contributors to the failure. The aim of the present study is to develop an evaluation method to study shear properties of the disc and to do a mathematical characterization of it. For the experiments, twelve porcine discs were used. Each disc was dissected from the TMJ and, then, static strain control tests were carried out to obtain the shear relaxation modulus for the central region of the discs. From the results, it was found that the disc presents a viscoelastic behavior under shear loads. Relaxation modulus decreased with time. Shear relaxation was 10% of the instantaneous stress, which implies that the viscous properties of the disc cannot be neglected. The present results lead to a better understanding of the discs mechanical behavior under realistic TMJ working conditions. 相似文献
15.
Tensile properties of the porcine temporomandibular joint disc 总被引:4,自引:0,他引:4
Despite the significant morbidity associated with the temporomandibular joint (TMJ), little is known about the pathophysiology of this complex joint. TMJ disc degeneration plays a central role in the progression of TMJ disorders, and therefore disc regeneration would be a crucial treatment modality. Unfortunately, scarce information about the structural and functional characteristics of the TMJ disc is available. The current study aims to provide a standard for the biomechanical behavior of the TMJ disc for future tissue engineering studies. The disc was loaded under uniaxial tension in two directions, mediolateral and anteroposterior, and in three locations per direction. In the mediolateral direction, the posterior band was 2.5 times stiffer, 2.4 times tougher (energy to maximum stress), and 2.2 times stronger than the anterior band, which was in turn 16 times stiffer and 5.7 times stronger than the intermediate zone. In the anteroposterior direction, the central and medial regions were 74% and 35% stiffer and 56% and 59% stronger than the lateral region, respectively, although similar to each other in strength and stiffness. There was no significant difference in toughness between regions in the anteroposterior direction. These results correlated qualitatively with collagen fiber orientation and fiber size obtained using polarized light microscopy. 相似文献
16.
M. Mesnard J. C. Coutant M. Aoun J. Morlier M. Cid P. Caix 《Computer methods in biomechanics and biomedical engineering》2013,16(4):393-400
Motions of the temporomandibular joint (TMJ) involve both translation and rotation; however, there may be substantial variations from one human to another, and these variations present significant difficulties when designing TMJ prostheses. The disc–condyle glides along the temporal bone and the condyle centre describe a curve that depends on the individual morphology. This study analyses disc–condyle rotatory and translatory displacements moving all along the temporal bone facets which are mainly composed of two areas: the articular tubercle slope (ATS) and the preglenoid plane separated by the articular tubercle crest. Displacements were quantified using 3D video analysis, and this technique was computer-assisted. From a population of 32 volunteers, we were able to establish a correlation between the kinematic characteristics of the joint and the disc–condyle trajectories. This study quantifies the geometrical characteristics of the ATS and their inter-individual variations, which are useful in TMJ prosthesis design. 相似文献
17.
Temporomandibular joint (TMJ) disorders affect up to 12% of the human population, and naturally occurring TMJ diseases are increasingly recognized in animals. The TMJ disc plays a major role in TMJ disorders in people, but little is known about its role in TMJ pathology in animals. This study characterizes differences in properties of equine TMJ discs associated with age, disc region, and presence of TMJ osteoarthritis (OA). Discs were dissected from both TMJ’s of sixteen horses euthanized for reasons unrelated to this study. Each joint was grossly evaluated and scored as normal, mild OA, or severe OA. Samples from the rostral, caudal, lateral, central, and medial regions of the disc were subject to compressive testing, quantitative biochemistry, and histology. Samples from the lateral, central, and medial region were tested for tensile properties in the rostrocaudal and mediolateral directions. We found that the equine TMJ disc is highly anisotropic, and its glycosaminoglycan (GAG) content and compressive stiffness vary between disc regions. The disc also exhibits increasing GAG content and compressive stiffness with increasing age. While equine TMJ disc properties are generally similar to other herbivores, greater compressive stiffness throughout the disc and greater GAG content in its rostral region suggest that mechanical demands on the TMJ disc differ between horses and other species. Importantly, a region-specific decrease in compressive stiffness was observed associated with joint disease and corresponded to cartilage erosions in the underlying condylar surface. 相似文献
18.
Mandibular condylar cartilage plays a crucial role in temporomandibular joint (TMJ) function, which includes facilitating articulation with the temporomandibular joint disc and reducing loads on the underlying bone. The cartilage experiences considerable tensile forces due to direct compression and shear. However, only scarce information is available about its tensile properties. The present study aims to quantify the biomechanical characteristics of the mandibular condylar cartilage to aid future three-dimensional finite element modeling and tissue engineering studies. Porcine condylar cartilage was tested under uniaxial tension in two directions, anteroposterior and mediolateral, with three regions per direction. Stress relaxation behavior was modeled using the Kelvin model and a second-order generalized Kelvin model, and collagen fiber orientation was determined by polarized light microscopy. The stress relaxation behavior of the tissue was biexponential in nature. The tissue exhibited greater stiffness in the anteroposterior direction than in the mediolateral direction as reflected by higher Young's (2.4 times), instantaneous (1.9 times), and relaxed (1.9 times) moduli. No significant differences were observed among the regional properties in either direction. The predominantly anteroposterior macroscopic fiber orientation in the fibrous zone of condylar cartilage correlated well with the biomechanical findings. The condylar cartilage appears to be less stiff and less anisotropic under tension than the anatomically and functionally related TMJ disc. The anisotropy of the condylar cartilage, as evidenced by tensile behavior and collagen fiber orientation, suggests that the shear environment of the TMJ exposes the condylar cartilage to predominantly but not exclusively anteroposterior loading. 相似文献
19.
Henrique Takashi Idogava Pedro Yoshito Noritomi Gregory Bregion Daniel 《Computer methods in biomechanics and biomedical engineering》2018,21(8):503-511
The temporomandibular joint (TMJ) is an anatomical set of the buco-maxillary system that allows the movement of the mandible in most varied ways. Several factors can influence the malfunctioning of the joint and lead to the use of a total prosthesis. However, current prostheses do not supply the maximum amplitude of movement during protrusion and opening, due to mainly the anatomical differences between patients. For this reason, this article aims to study the patient’s kinematic characteristics for a better comprehension of the problem and, consequently, to develop a numerical model for TMJ prostheses able to recover the healthy movement. The numerical model is based on the development of a mechanical joint whose profile is able to reproduce the movement of the health system. The results obtained through the developed model showed a good agreement with the experimental results, representing, therefore, a promising alternative to approach the problems related to TMJ. 相似文献
20.
Willard VP Kalpakci KN Reimer AJ Athanasiou KA 《Journal of biomechanical engineering》2012,134(1):011011
Understanding structure-function relationships in the temporomandibular joint (TMJ) disc is a critical first step toward creating functional tissue replacements for the large population of patients suffering from TMJ disc disorders. While many of these relationships have been identified for the collagenous fraction of the disc, this same understanding is lacking for the next most abundant extracellular matrix component, sulfated glycosaminoglycans (GAGs). Though GAGs are known to play a major role in maintaining compressive integrity in GAG-rich tissues such as articular cartilage, their role in fibrocartilaginous tissues in which GAGs are much less abundant is not clearly defined. Therefore, this study investigates the contribution of GAGs to the regional viscoelastic compressive properties of the temporomandibular joint (TMJ) disc. Chondroitinase ABC (C-ABC) was used to deplete GAGs in five different disc regions, and the time course for >95% GAG removal was defined. The compressive properties of GAG depleted regional specimens were then compared to non-treated controls using an unconfined compression stress-relaxation test. Additionally, treated and non-treated specimens were assayed biochemically and histologically to confirm GAG removal. Compared to untreated controls, the only regions affected by GAG removal in terms of biomechanical properties were in the intermediate zone, the most GAG-rich portion of the disc. Without GAGs, all intermediate zone regions showed decreased tissue viscosity, and the intermediate zone lateral region also showed a 12.5% decrease in modulus of relaxation. However, in the anterior and posterior band regions, no change in compressive properties was observed following GAG depletion, though these regions showed the highest compressive properties overall. Although GAGs are not the major extracellular matrix molecule of the TMJ disc, they are responsible for some of the viscoelastic compressive properties of the tissue. Furthermore, the mechanical role of sulfated GAGs in the disc varies regionally in the tissue, and GAG abundance does not always correlate with higher compressive properties. Overall, this study found that sulfated GAGs are important to TMJ disc mechanics in the intermediate zone, an important finding for establishing design characteristics for future tissue engineering efforts. 相似文献