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Eiji Tanaka - One of the best experts on this subject based on the ideXlab platform.
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effect of region dependent viscoelastic properties on the tmj Articular Disc relaxation under prolonged clenching
Journal of The Mechanical Behavior of Biomedical Materials, 2021Co-Authors: Natalia Tielve Garcia, Eiji Tanaka, Pelayo Fernandez, Eva Barrientos, Maria Jesus Lamelarey, Alfonso Fernandezcanteli, Juan Carlos De VicenteAbstract:Abstract The Disc of the temporomandibular joint (TMJ) is located between the mandibular condyle and temporal bone, and has an important load-bearing and stress absorbing function. The TMJ Disc presents viscoelastic characteristics that are largely dependent on its collagen fibre and proteoglycan composition and organization. The purpose of this study is to investigate the possible effects of region-specific dynamic viscoelastic properties on stress relaxation during prolonged clenching. Two finite element models were used to compare the stress distribution within the TMJ Disc, namely, one with uniform Disc material property and another one with region-specific Disc material properties. Similar results were observed in both models with slight differences in the location of maximum stress. Larger stresses were observed in all cases for the model with uniform Disc material property. Moreover, the higher values for the model with uniform Disc material property appeared in the lateral region, while in the model with region-specific Disc properties, these values moved to the lateral and central region. This investigation confirms that both models are sufficiently accurate to investigate stress distribution in the TMJ Disc, and, pArticularly, the model with the region-specific Disc material properties ensure better simulations of the TMJ Disc behaviour.
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Quasi-Linear Viscoelastic Model of the Articular Disc of the Temporomandibular Joint
Experimental Mechanics, 2016Co-Authors: Maria S. Commisso, J. Mayo, Eiji Tanaka, J.l. Calvo-gallego, J. Martínez-reinaAbstract:A precise characterization of the Articular Disc of the temporomandibular joint (TMJ) is essential to study the masticatory biomechanics. The Disc is responsible for the load distribution over the Articular surface and for absorbing impacts during mastication. The main objective of this work is to characterize the mechanical behaviour of the Articular Disc under compression, the usual stress state during mastication. A quasi-linear viscoelastic (QLV) model, with a hyperelastic response for the elastic function, is proposed to describe the mechanical behaviour of the Articular Disc. The validity of that simplified model relies on the independence of their constants with the strain level and strain rate. The independence of the strain level was proved in a previous work. In this paper, different loading rates were tested to fully confirm the validity of the model in the physiological range of loads. Moreover, the strong non-linearity of the stress-strain relation made the exponential strain energy function the most suitable of the different models tried to represent the elastic response of the QLV model.
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tensile stress patterns predicted in the Articular Disc of the human temporomandibular joint
Journal of Anatomy, 2009Co-Authors: J H Koolstra, Eiji TanakaAbstract:The direction of the first principal stress in the Articular Disc of the temporomandibular joint was predicted with a biomechanical model of the human masticatory system. The results were compared with the orientation of its collagen fibers. Furthermore, the effect of an active pull of the superior lateral pterygoid muscle, which is directly attached to the Articular Disc, was studied. It was hypothesized that the markedly antero-posterior direction of the collagen fibers would be reflected in the direction of the tensile stresses in the Disc and that active pull of the superior lateral pterygoid muscle would augment these tensions. It was found that the tensile patterns were extremely dependent on the stage of movement and on the mandibular position. They differed between the superior and inferior layers of the Disc. The hypothesis could only be confirmed for the anterior and middle portions of the Disc. The predicted tensile principal stresses in the posterior part of the Disc alternated between antero-posterior and medio-lateral directions.
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the role of Articular Disc in the tmj and its viscoelastic properties
The Journal of Japanese Society of Stomatognathic Function, 2004Co-Authors: Eiji TanakaAbstract:顎関節円板は下顎頭と下顎窩との間に介在する線維軟骨性組織である.その主な構成成分はコラーゲン線維とその線維の間隙を満たすプロテオグリカンであり, これらの構成成分が顎関節円板の持つ粘弾性特性に関連している.結果として顎関節円板は機能時に応力緩衝帯としての重要な役割を果たしている.円板の有する粘弾性特性は負荷の方向, 大きさ, 速度および様式によって大きく異なる.加えて, この特性は加齢, 外傷, 疾患のように一生のうちに生じる内因性あるいは外因性の因子によって変化するものである.このように多様な顎関節円板の力学特性に関する情報は顎関節円板に対する再生医学の進歩には必要不可欠である.本稿では, 顎関節円板の様々な力学的環境における生体力学的性状を紹介するとともに, 最適な顎関節置換物の開発や顎関節円板の再生医学の可能性について考察する.
Siegfried Trattnig - One of the best experts on this subject based on the ideXlab platform.
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early diagnosis of degenerative changes in the Articular fibrocartilaginous Disc of the temporomandibular joint in patients with temporomandibular disorders using delayed gadolinium enhanced mri at 3 tesla preliminary results
Magnetic Resonance Imaging, 2020Co-Authors: Jaryna Eder, Martina Schmidschwap, Margit Bristela, Elisabeth Pittschieler, Astrid Skolka, Pavol Szomolanyi, Eva Piehslinger, Siegfried TrattnigAbstract:Abstract Background Delayed gadolinium enhanced MRI of cartilage (dGEMRIC) is a quantitative method for assessment of glycosaminoglycan content in connective tissues. We hypothesize that the early diagnosis of degenerative changes in the temporomandibular joint could be diagnosed using dGEMRIC technique. Purpose To test the compositional MRI technique, dGEMRIC, at 3 Tesla to diagnosis early the degenerative changes in the fibrocartilaginous Disc of the temporomandibular joint (TMJ) in patients with temporomandibular disorders (TMD) and to compare the dGEMRIC index of patients to the healthy volunteers. Methods Six volunteers (two men, four women; 20.8÷28.1 years) and eleven patients (22 TMJs, seven women, four men; 24÷54 years) were recruited for this prospective trial. Only patients with no morphological abnormality on MRI and without Disc dislocations were included. Volunteers were used as a control group. The PD-weighted FSE sequence and the 3D GRE (DESS) sequence protocols were performed for morphological assessment. The Inversion recovery (IR) sequence was performed for T1 relaxation time measurements and intra-venous (IV) contrast agent administration was used according to the dGEMRIC protocol. T1 maps were calculated offline and ROIs were drawn on TMJ Discs by a specialist trained in TMD disorders. Statistical evaluation was performed by ANOVA and correlations were calculated. Results The difference between the dGEMRIC values in the TMJ Articular Discs of the patients and the volunteers was statistically significant (P = .019). After contrast agent administration the T1 values dropped in both groups. In patient group was the T1 drop stronger (−54% from initial pre-contrast value), while in control group was the T1 drop less pronounced (−46% from initial pre-contrast value). Conclusions dGEMRIC seems to be a useful, compositional, quantitative method, suitable also for small joints, such as the Articular Disc of the TMJ. The results of the dGEMRIC index in the Articular Disc of the TMJ imply a lower GAG content in patients with TMJ disorders.
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biochemical analysis of the Articular Disc of the temporomandibular joint with magnetic resonance t2 mapping a feasibility study
Clinical Oral Investigations, 2014Co-Authors: Martina Schmidschwap, Margit Bristela, Elisabeth Pittschieler, Astrid Skolka, Pavol Szomolanyi, Michael Weber, Eva Piehslinger, Siegfried TrattnigAbstract:Symptoms of temporomandibular joint (TMJ) dysfunction can seriously compromise patients' quality of life. The aim of our study was to use magnetic resonance imaging (MRI) T2 mapping of the Articular Disc to determine whether T2 mapping of the TMJ Disc is feasible in routine clinical imaging and to assess the normal T2 relaxation time distribution within the TMJ. Included were ten asymptomatic volunteers without pain, any mouth-opening limitations, or any clicking phenomena. MR imaging was performed on a 3-T MR scanner using a flexible, dedicated, eight-channel multielement coil. T2 mapping was performed in the oblique sagittal plane. The regions of interest (ROIs) for the T2 relaxation time maps of the Disc were selected manually. The mean values for ROIs ranged between 22.4 and 28.8 ms, and the mean for all ROIs was 26.0 ± 5.0 ms. Intraclass correlation (ICC) for interobserver variability was 0.698, and ICC for intraobserver variability was 0.861. There was no statistically significant difference between raters (p = 0.091) or sides (p = 0.810). The T2 mapping technique enables ultrastructural analysis of the composition of TMJ Disc. This biochemical technique is feasible in vivo, as shown in our study, when a high-field (3 T) MR and a dedicated TMJ coil are used. T2 mapping as a biochemical technique, together with morphological MRI, may help to gain more insights into the physiology and into the pathophysiology of the Articular Disc in the TMJ noninvasively and in vivo.
J H Koolstra - One of the best experts on this subject based on the ideXlab platform.
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tensile stress patterns predicted in the Articular Disc of the human temporomandibular joint
Journal of Anatomy, 2009Co-Authors: J H Koolstra, Eiji TanakaAbstract:The direction of the first principal stress in the Articular Disc of the temporomandibular joint was predicted with a biomechanical model of the human masticatory system. The results were compared with the orientation of its collagen fibers. Furthermore, the effect of an active pull of the superior lateral pterygoid muscle, which is directly attached to the Articular Disc, was studied. It was hypothesized that the markedly antero-posterior direction of the collagen fibers would be reflected in the direction of the tensile stresses in the Disc and that active pull of the superior lateral pterygoid muscle would augment these tensions. It was found that the tensile patterns were extremely dependent on the stage of movement and on the mandibular position. They differed between the superior and inferior layers of the Disc. The hypothesis could only be confirmed for the anterior and middle portions of the Disc. The predicted tensile principal stresses in the posterior part of the Disc alternated between antero-posterior and medio-lateral directions.
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prediction of volumetric strain in the human temporomandibular joint cartilage during jaw movement
Journal of Anatomy, 2006Co-Authors: J H Koolstra, T M G J Van EijdenAbstract:Human temporomandibular joint loading causes pressurization and flow of interstitial fluid in its cartilaginous structures. This largely determines its load-bearing and maintenance capacity. It was hypothesized that during cyclical jaw movements normal pressure distribution dynamics would enable fluid to reach all necessary cartilage regions. This was tested qualitatively by analysis of local volumetric strain dynamics during jaw open–close movements predicted by a dynamic model of the human masticatory system. Finite-element analysis was performed in separate regions of the Articular cartilage layers and Articular Disc. Heterogeneous patterns of dilatation and compression were predicted. Compression was found to be more dominant during jaw closing than opening. The pressure gradient in the superior layer of the Articular Disc was more mediolaterally orientated than in its inferior layer. The findings suggest that, where necessary, regionally the cartilage can imbibe fluid to protect the subchondral bone from impact loads effectively. In the Disc itself presumably all areas receive regular refreshment of interstitial fluid.
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combined finite element and rigid body analysis of human jaw joint dynamics
Journal of Biomechanics, 2005Co-Authors: J H Koolstra, T M G J Van EijdenAbstract:The jaw joint plays a crucial role in human mastication. It acts as a guidance for jaw movements and as a fulcrum for force generation. The joint is subjected to loading which causes tensions and deformations in its cartilaginous structures. These are assumed to be a major determinant for development, maintenance and also degeneration of the joint. To analyze the distribution of tensions and deformations in the cartilaginous structures of the jaw joint during jaw movement, a dynamical model of the human masticatory system has been constructed. Its movements are controlled by muscle activation. The Articular cartilage layers and Articular Disc were included as finite-element (FE) models. As this combination of rigid-body and FE modeling had not been applied to musculoskeletal systems yet, its benefits and limitations were assessed by simulating both unloaded and loaded jaw movements. It was demonstrated that joint loads increase with muscle activation, irrespective of the external loads. With increasing joint load, the size of the stressed area of the Articular surfaces was enlarged, whereas the peak stresses were much less affected. The results suggest that the Articular Disc enables distribution of local contact stresses over a much wider area of the very incongruent Articular surfaces by transforming compressive principal stress into shear stress.
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three dimensional finite element analysis of the human temporomandibular joint Disc
Journal of Biomechanics, 2000Co-Authors: M Beek, J H Koolstra, L J Van Ruijven, T M G J Van EijdenAbstract:Abstract A three-dimensional finite element model of the Articular Disc of the human temporomandibular joint has been developed. The geometry of the Articular cartilage and Articular Disc surfaces in the joint was measured using a magnetic tracking device. First, polynomial functions were fitted through the coordinates of these scattered measurements. Next, the polynomial description was transformed into a triangulated description to allow application of an automatic mesher. Finally, a finite element mesh of the Articular Disc was created by filling the geometry with tetrahedral elements. The articulating surfaces of the mandible and skull were modeled by quadrilateral patches. The finite element mesh and the patches were combined to create a three-dimensional model in which unrestricted sliding of the Disc between the articulating surfaces was allowed. Simulation of statical joint loading at the closed jaw position predicted that the stress and strain distributions were located primarily in the intermediate zone of the Articular Disc with the highest values in the lateral part. Furthermore, it was predicted that considerable deformations occurred for relatively small joint loads and that relatively large variations in the direction of joint loading had little influence on the distribution of the deformations.
William B. Kleinman - One of the best experts on this subject based on the ideXlab platform.
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Management of chronic peripheral tears of the triangular fibrocartilage complex
The Journal of Hand Surgery, 1991Co-Authors: John D. Hermansdorfer, William B. KleinmanAbstract:Injury to the triangular fibrocartilage is recognized with increasing frequency as a major source of pain on the ulnar side of the wrist. Traumatic separation of the well-vascularized medial insertion of the triangular fibrocartilage complex at the fovea of the ulnar styloid is less common than attritional perforation of the central hypovascular Articular Disc. Thirteen patients with traumatic separation of the triangular fibrocartilage complex from its peripheral origin (eleven with documented single-episode antecedant trauma) had anatomic reconstitution by surgical reattachment to the ulna. After postoperative rehabilitation, return to essentially normal painless activities was reached in eight of eleven patients with follow-up greater than one year. Two of the three unsatisfactory results responded well to subsequent surgery (distal ulna resection; ulnar shortening osteotomy); one patient has been unable to return to competitive gymnastics and seeks no further treatment.
Susanne Rein - One of the best experts on this subject based on the ideXlab platform.
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degeneration of the Articular Disc in the human triangular fibrocartilage complex
Archives of Orthopaedic and Trauma Surgery, 2021Co-Authors: Susanne Rein, Veit Krenn, Elisabet Hagert, Marc Garciaelias, A Lluch, Thomas Kremer, Manuel SemischAbstract:Traumatic injuries of the triangular fibrocartilage complex (TFCC) are frequent reasons for ulnar wrist pain. The assessment of the extent of Articular Disc (AD) degeneration is important for the differentiation of acute injuries versus chronic lesions. The AD of the TFCC of eleven human cadaver wrists was dissected. Degeneration was analyzed according to the grading of Krenn et al. Hematoxylin–eosin was used to determine the tissue morphology. Degeneration was evaluated using the staining intensity of alcian blue, the immunohistochemistry of the proteoglycan versican and the immunoreactivity of NITEGE, an aggrecan fragment. The staining homogeneity of HE decreased with higher degeneration of the AD and basophilic tissue areas were more frequently seen. Two specimens were characterized as degeneration grade 1, five specimens as grade 2, and four specimens as grade 3, respectively. Staining intensity of alcian blue increased with higher degeneration grade of the specimens. Immunoreactivity for NITEGE was detected around tissue fissures and perforations as well as matrix splits. Immunoreactivity for versican was found concentrated in the tissue around matrix fissures and lesions as well as loose connective tissue at the ulnar border of the AD. Specimens with degeneration grade 2 had the strongest immunoreactivity of NITEGE and versican. Cell clusters were observed in specimens with degeneration grade 2 and 3, which were stained by alcian blue and immunoreactive for NITEGE and versican. Increasing age of the cadaver wrists correlated with a higher degree of degeneration (p < 0.0001, r = 0.68). The fibrocartilage of degenerated ADs contains NITEGE and versican. The amount of the immunoreactivity of these markers allows the differentiation of degenerative changes into three grades. The degeneration of the AD increases with age and emphasizes its important mechanical function.
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Histological assessment of the triangular fibrocartilage complex
Journal of Hand Surgery (European Volume), 2015Co-Authors: Manuel Semisch, Elisabet Hagert, M. Garcia-elias, Alex Lluch, Susanne ReinAbstract:The morphological structure of the seven components of triangular fibrocartilage complexes of 11 cadaver wrists of elderly people was assessed microscopically, after staining with Hematoxylin-Eosin and Elastica van Gieson. The Articular Disc consisted of tight interlaced fibrocartilage without blood vessels except in its ulnar part. Volar and dorsal radioulnar ligaments showed densely parallel collagen bundles. The subsheath of the extensor carpi ulnaris muscle, the ulnotriquetral and ulnolunate ligament showed mainly mixed tight and loose parallel tissue. The ulnolunate ligament contained tighter parallel collagen bundles and clearly less elastic fibres than the ulnotriquetral ligament. The ulnocarpal meniscoid had an irregular morphological composition and loose connective tissue predominated. The structure of the Articular Disc indicates a buffering function. The tight structure of radioulnar and ulnolunate ligaments reflects a central stabilizing role, whereas the ulnotriquetral ligament and ulnocarpal meniscoid have less stabilizing functions.
