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Ortún-Terrazas J, Fagan MJ, Cegoñino J, Illipronti-Filho E, Del Palomar AP. Biomechanical evaluation of the unilateral crossbite on the asymmetrical development of the craniofacial complex. A mechano-morphological approach. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 217:106703. [PMID: 35217305 DOI: 10.1016/j.cmpb.2022.106703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/27/2022] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE The occlusion effect on the craniofacial development is a controversial topic that has attracted the interest of many researchers but that remains unclear, mainly due to the difficulties on measure its mechanical response experimentally. This mechano-morphological relationship of the craniofacial growth is often explained by the periosteal and capsular matrices of the functional matrix hypothesis (FMH); however, its outcomes have not been analytically demonstrated yet. This computational study aims, therefore, to analytically demonstrate the mechano-morphological relationship in the craniofacial development of children with unilateral crossbite (UXB) using the finite element (FE) method. METHODS The craniofacial complex asymmetry of ten children, five of whom exhibit UXB, was 3D-analysed and compared with the biomechanical response computed from a FE analysis of each patient's occlusion. Due to the complexity of the geometry and the multitude of contacts involved, the inherent limitations of the model were evaluated by comparing computed occlusal patterns with those recorded by an occlusal analysis on 3D printed copies. RESULTS Comparison's outcomes proved the reliability of our models with just a deviation error below 6% between both approaches. Out of validation process, computational results showed that the significant elongation of mandibular branch in the contralateral side could be related to the mandibular shift and increase of thickness on the crossed side, and particularly of the posterior region. These morphological changes could be associated with periodontal overpressure (>4.7 kPa) and mandibular over deformation (0.002 ε) in that side, in agreement with the periosteal matrix's principles. Furthermore, the maxilla's transversal narrowing and the elevation of the maxillary and zygomatic regions on the crossed side were statistically demonstrated and seem to be related with their respective micro displacements at occlusion, as accounted by their specific capsule matrices. Our results were consistent with those reported clinically and demonstrated analytically the mechano-morphological relationship of children's craniofacial development based on the FMH's functional matrices. CONCLUSIONS This study is a first step in the understanding of the occlusion's effect on the craniofacial development by computational methods. Our approach could help future engineers, researchers and clinicians to understand better the aetiology of some dental malocclusions and functional disorders improve the diagnosis or even predict the craniofacial development.
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Affiliation(s)
- Javier Ortún-Terrazas
- Group of Biomaterials, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain.
| | - Michael J Fagan
- Medical and Biological Engineering, School of Engineering and Computer Science, University of Hull, Hull, United Kingdom
| | - José Cegoñino
- Group of Biomaterials, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - Edson Illipronti-Filho
- School of Dentistry, Department of Stomatology, University of São Paulo, São Paulo, Brazil
| | - Amaya Pérez Del Palomar
- Group of Biomaterials, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
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Ortún-Terrazas J, Cegoñino J, Pérez Del Palomar A. Biomechanical impact of the porous-fibrous tissue behaviour in the temporomandibular joint movements. An in silico approach. J Mech Behav Biomed Mater 2021; 120:104542. [PMID: 33962235 DOI: 10.1016/j.jmbbm.2021.104542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 11/28/2022]
Abstract
The movement of the temporomandibular joint (TMJ) is a function of its complex geometry and its interaction with the surrounding soft tissues. Owing to an increase in the prevalence of temporomandibular joint disorders (TMDs), many computational studies have attempted to characterize its biomechanical behaviour in the last 2 decades. However, most such studies are based on a single computational model that markedly simplifies the complex geometry and mechanical properties of the TMJ's soft tissues. The present study aims to computationally evaluate in a wider sample the importance of considering their complex anatomy and behaviour for simulating both damping and motion responses of this joint. Hence, 6 finite element models of healthy volunteers' TMJ were developed and subjected to both conditions in two different behavioural scenarios. In one, the soft tissues' behaviour was modelled by considering the porous-fibrous properties, whereas in the other case they were simplified assuming isotropic-hyperelastic response, as had been traditionally considered. The damping analysis, which mimic the conditions of an experimental test of the literature, consisted of applying two different compressive loads to the jaw. The motion analysis evaluated the condylar path during the mandible centric depression by the action of muscular forces. From the results of both analyses, the contact pressures, intra-articular fluid pressure, path features, and stress/strain values were compared using the porous-fibrous and isotropic-hyperelastic models. Besides the great differences observed between patients due patient-specific morphology, the porous-fibrous approach yielded results closer to the reference experimental values and to the outcomes of other computational studies of the literature. Our findings underscore, therefore, the importance of considering realistic joint geometries and porous-fibrous contribution in the computational modelling of the TMJ, but also in the design of further joint replacements or in the development of new biomaterials for this joint.
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Affiliation(s)
- Javier Ortún-Terrazas
- Group of Biomaterials, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain.
| | - José Cegoñino
- Group of Biomaterials, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - Amaya Pérez Del Palomar
- Group of Biomaterials, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
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Ortún-Terrazas J, Cegoñino J, Illipronti-Filho E, Pérez del Palomar A. Analysis of temporomandibular joint dysfunction in paediatric patients with unilateral crossbite using automatically generated finite element models. Comput Methods Biomech Biomed Engin 2020; 23:627-641. [DOI: 10.1080/10255842.2020.1755275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | - José Cegoñino
- Department of Mechanical Engineering, University of Zaragoza, Zaragoza, Spain
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Mirow E, Sifakakis I, Keilig L, Bourauel C, Patcas R, Eliades T, Dörsam I. Quantitative appraisal of bilateral sagittal split osteotomy impact on the loading of temporomandibular joint. J Mech Behav Biomed Mater 2020; 111:103985. [PMID: 32861207 DOI: 10.1016/j.jmbbm.2020.103985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/08/2020] [Accepted: 07/11/2020] [Indexed: 11/19/2022]
Abstract
Bilateral sagittal split osteotomy is one of the most frequently performed operations in orthognathic surgery. The health of the temporomandibular joint (TMJ) is an important prerequisite for its functionality. The aim of this finite element study was to assess the developed stresses during mouth opening after bilateral sagittal split osteotomy. Different osteotomy gap widths and disc positions were evaluated. Computed tomography and magnetic resonance data of a dentulous cadaver head were used in order to create two finite element models simulating split distances of 5 and 10 mm, respectively. The fixation of the distal and proximal segments was made by a four- or a six-hole titanium mini plate and four monocortical screws respectively. For both models, three different situations of the articular disc were created: a physiological disc position, anterior disc displacement and posterior disc displacement. The mandible was vertically displaced in the midline in order to simulate a mouth opening of 20 mm. The simulation showed high stresses in the area of the titanium plates (up to 850 MPa), implying an increased risk of material failure. High stresses were found within the discs in the models with normal disc position and anterior disc displacement as well (up to 8 MPa), indicating a higher risk of developing craniomandibular disorders. Regarding the stresses within the fixation screws, the highest values were recorded in the area of the upper thread. The degree of mandibular advancement after a bilateral sagittal split osteotomy affects the stress balance in the mandible and the articular discs during mouth opening.
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Affiliation(s)
- Eva Mirow
- Oral Technology, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany
| | - Iosif Sifakakis
- Department of Orthodontics, School of Dentistry, University of Athens, 2 Thivon Str, 115 27, Goudi, Athens, Greece
| | - Ludger Keilig
- Oral Technology, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany; Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany
| | - Christoph Bourauel
- Oral Technology, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany
| | - Raphael Patcas
- Clinic of Orthodontics and Pediatric Dentistry, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland
| | - Istabrak Dörsam
- Oral Technology, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany; Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany.
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Tanne K, Okamoto Y, Su SC, Mitsuyoshi T, Asakawa-Tanne Y, Tanimoto K. Current status of temporomandibular joint disorders and the therapeutic system derived from a series of biomechanical, histological, and biochemical studies. APOS TRENDS IN ORTHODONTICS 2014. [DOI: 10.4103/2321-1407.148014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
This article was designed to report the current status of temporomandibular joint disorders (TMDs) and the therapeutic system on the basis of a series of clinical, biomechanical, histological and biochemical studies in our research groups. In particular, we have focused on the association of degenerative changes of articular cartilage in the mandibular condyle and the resultant progressive condylar resorption with mechanical stimuli acting on the condyle during the stomatognathic function. In a clinical aspect, the nature and prevalence of TMDs, association of malocclusion with TMDs, association of condylar position with TMDs, association of craniofacial morphology with TMDs, and influences of TMDs, TMJ-osteoarthritis (TMJ-OA) in particular, were examined. In a biomechanical aspect, the nature of stress distribution in the TMJ from maximum clenching was analyzed with finite element method. In addition, the pattern of stress distribution was examined in association with varying vertical discrepancies of the craniofacial skeleton and friction between the articular disk and condyle. The results demonstrated an induction of large compressive stresses in the anterior and lateral areas on the condyle by the maximum clenching and the subsequent prominent increases in the same areas of the mandibular condyle as the vertical skeletal discrepancy became more prominent. Increase of friction at the articular surface was also indicated as a cause of larger stresses and the relevant disk displacement, which further induced an increase in stresses in the tissues posterior to the disks, indicating an important role of TMJ disks as a stress absorber. In a histological or biological aspect, increase in TMJ loading simulated by vertical skeletal discrepancy, which has already been revealed by the preceding finite element analysis or represented by excessive mouth opening, produced a decrease in the thickness of cartilage layers, an increase in the numbers of chondroblasts and osteoclasts and the subsequent degenerative changes in the condylar cartilage associated with the expression of bone resorption-related factors. In a biochemical or molecular and cellular aspect, excessive mechanical stimuli, irrespective of compressive or tensile stress, induced HA fragmentation, expression of proinflammatory cytokines, an imbalance between matrix metalloproteinases and the tissue inhibitors, all of which are assumed to induce lower resistance to external stimuli and degenerative changes leading to bone and cartilage resorption. Excessive mechanical stimuli also reduced the synthesis of superficial zone protein in chondrocytes, which exerts an important role in the protection of cartilage and bone layers from the degenerative changes. It is also revealed that various cytoskeletal changes induced by mechanical stimuli are transmitted through a stretch-activated or Ca2+channel. Finally, on the basis of the results from a series of studies, it is demonstrated that optimal intra-articular environment can be achieved by splint therapy, if indicated, followed by occlusal reconstruction with orthodontic approach in patients with myalgia of the masticatory muscles, and TMJ internal derangement or anterior disk displacement with or without reduction. It is thus shown that orthodontic treatment is available for the treatment of TMDs and the long-term stability after treatment.
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Affiliation(s)
- Kazuo Tanne
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yuki Okamoto
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
| | - Shao-Ching Su
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
| | - Tomomi Mitsuyoshi
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
| | - Yuki Asakawa-Tanne
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
| | - Kotaro Tanimoto
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
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Li Q, Ren S, Ge C, Sun H, Lu H, Duan Y, Rong Q. Effect of jaw opening on the stress pattern in a normal human articular disc: finite element analysis based on MRI images. Head Face Med 2014; 10:24. [PMID: 24943463 PMCID: PMC4082420 DOI: 10.1186/1746-160x-10-24] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/13/2014] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Excessive compressive and shear stresses are likely related to condylar resorption and disc perforation. Few studies have reported the disc displacement and deformation during jaw opening. The aim of this study was to analyze stress distribution in a normal articular disc during the jaw opening movement. METHODS Bilateral MRI images were obtained from the temporomandibular joint of a healthy subject for the jaw opening displacement from 6 to 24 mm with 1 mm increments. The disc contour for the jaw opening at 6 mm was defined as the reference state, and was used to establish a two dimensional finite element model of the disc. The contours of the disc at other degrees of jaw opening were used as the displacement loading. Hyperelastic material models were applied to the anterior, intermediate and posterior parts of the disc. Stress and strain trajectories were calculated to characterize the stress/strain patterns in the disc. RESULTS Both the maximum and minimum principal stresses were negative in the intermediate zone, therefore, the intermediate zone withstood mainly compressive stress. On the contrary, the maximum and minimum principal stresses were most positive in the anterior and posterior zones, which meant that the anterior and posterior bands suffered higher tensile stresses. The different patterns of stress trajectories between the intermediate zone and the anterior and posterior bands might be attributed to the effect of fiber orientation. The compression of the intermediate zone and stretching of the anterior and posterior bands caused high shear deformation in the transition region, especially at the disc surfaces. CONCLUSIONS The stress and strain remained at a reasonable level during jaw opening, indicating that the disc experiences no injury during functional opening movements in a healthy temporomandibular joint.
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Affiliation(s)
| | | | | | | | | | | | - Qiguo Rong
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.
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Aoun M, Mesnard M, Monède-Hocquard L, Ramos A. Stress Analysis of Temporomandibular Joint Disc During Maintained Clenching Using a Viscohyperelastic Finite Element Model. J Oral Maxillofac Surg 2014; 72:1070-7. [DOI: 10.1016/j.joms.2013.11.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/19/2013] [Accepted: 11/29/2013] [Indexed: 10/25/2022]
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Ueki K, Moroi A, Sotobori M, Ishihara Y, Marukawa K, Takatsuka S, Yoshizawa K, Kato K, Kawashiri S. A hypothesis on the desired postoperative position of the condyle in orthognathic surgery: a review. Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 114:567-76. [DOI: 10.1016/j.oooo.2011.12.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 12/08/2011] [Indexed: 10/28/2022]
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Freire Matos M, Durst AC, Freire Matos JL, Learreta JA. Electromyographic evaluation of the 'vertical' dimension: the Learreta TMJ decompression test. Cranio 2011; 29:255-60. [PMID: 22128664 DOI: 10.1179/crn.2011.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The clinical observation of the incisors overbite is the most common form used to evaluate the occlusal vertical dimension (OVD); however, this technique offers poor information about the compression state of the TMJ. In order to obtain such information, it is necessary to evaluate the electrical activity of the elevator muscles using surface electromyography (EMG). In case of a compressive irritation of the joint receptors, the trigeminal nucleus returns an inhibitory motor response of the elevator muscles that can be measured. The Learreta's EMG decompression test is done by measuring the EMG response of the masticatory muscles at maximal occlusion in four different OVD positions in such a way that the reduction of the TMJ pressure, and subsequently, relief of the inhibitory motor response can be studied. The aim of this study is to illustrate this technique, its clinical use and its limitations.
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Ueki K, Nakagawa K, Marukawa K, Yamamoto E, Takeuchi N. Stress change on the temporomandibular joint in mandibular prognathism subjects with asymmetry after orthognathic surgery. Eur J Orthod 2010; 32:522-9. [DOI: 10.1093/ejo/cjp143] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Ueki K, Takeuchi N, Nakagawa K, Yamamoto E. Simplified stress analysis on the temporomandibular joint in Class III patients with and without mandibular asymmetry using a rigid body spring model. Orthod Craniofac Res 2009; 12:312-8. [DOI: 10.1111/j.1601-6343.2009.01467.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lumpkins SB, McFetridge PS. Regional variations in the viscoelastic compressive properties of the temporomandibular joint disc and implications toward tissue engineering. J Biomed Mater Res A 2009; 90:784-91. [DOI: 10.1002/jbm.a.32148] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Effects of condylar elastic properties to temporomandibular joint stress. J Biomed Biotechnol 2009; 2009:509848. [PMID: 19644555 PMCID: PMC2715898 DOI: 10.1155/2009/509848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 05/18/2009] [Indexed: 11/18/2022] Open
Abstract
Mandibular condyle plays an important role in the growth and reconstruction of the temporomandibular joint (TMJ). We aimed to obtain orthotropic elastic parameters of the condyle using a continuous-wave ultrasonic technique and to observe the effects of condylar elastic parameters on stress distribution of the TMJ using finite element analysis (FEA). Using the ultrasonic technique, all nine elastic parameters were obtained, which showed that the mandibular condyle was orthotropic. With the condyle defined as orthotropic, the occlusal stress was transferred fluently and uniformly from the mandible to the TMJ. The stress distribution in the isotropic model showed stepped variation among different anatomical structures with higher stress values in the cartilage and condyle than in the orthotropic model. We conclude that anisotropy has subtle yet significant effects on stress distribution of the TMJ and could improve the reality of simulations.
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Gupta A, Kohli VS, Hazarey PV, Kharbanda OP, Gunjal A. Stress distribution in the temporomandibular joint after mandibular protraction: A 3-dimensional finite element method study. Part 1. Am J Orthod Dentofacial Orthop 2009; 135:737-48. [DOI: 10.1016/j.ajodo.2007.12.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2007] [Revised: 12/12/2007] [Accepted: 12/12/2007] [Indexed: 11/28/2022]
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Athanasiou KA, Almarza AJ, Detamore MS, Kalpakci KN. Tissue Engineering of Temporomandibular Joint Cartilage. ACTA ACUST UNITED AC 2009. [DOI: 10.2200/s00198ed1v01y200906tis002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Liu Z, Fan Y, Qian Y. Comparative evaluation on three-dimensional finite element models of the temporomandibular joint. Clin Biomech (Bristol, Avon) 2008; 23 Suppl 1:S53-8. [PMID: 18282646 DOI: 10.1016/j.clinbiomech.2007.12.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 02/07/2023]
Abstract
BACKGROUND The loads in the temporomandibular joint (TMJ) have been proven to play an important role in its structure and function as well as the etiology and therapy of TMJ disorders. Up to now, finite element (FE) models have been largely used to analyze the stress distributions in TMJs. The disc and the articular surfaces in the TMJs were simulated to be bonded together in many models. In addition, gap elements or contact elements were used to simulate the interaction of the disc and the articular surfaces. However, the comparative evaluation of the three simulations of TMJs has not been studied. METHODS Three FE models were developed to compare the differences of the simulations on the biomechanics of the TMJs according to the CT images of a volunteer. The interfaces between the discs and the articular cartilages were bonded together and treated as gap elements or contact elements. The muscle forces corresponding to centric occlusion were applied to the three models. FINDINGS The stresses in the TMJs were observed to increase in the model with bonded discs and articular cartilages. Gap elements between the discs and the cartilages resulted in the slight magnitude of stresses and the abnormal movement and stress distribution in the TMJs. The condyles and the discs were in the normal position and the stress distributions in the TMJs were similar to the normal biomechanical states when contact elements were simulated between the disc and the cartilages. INTERPRETATION The reasonable simulation of the TMJs was to treat the interfaces between the discs and the cartilages as contact elements. The reliable simulation could contribute to the understanding of the stress distributions in TMJs and the basis for the prevention and therapy of the TMJ disorders.
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Affiliation(s)
- Zhan Liu
- Laboratory of Biomechanical Engineering, Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
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Tanaka E, Tanaka M, Watanabe M, Del Pozo R, Tanne K. Influences of occlusal and skeletal discrepancies on biomechanical environment in the TMJ during maximum clenching: an analytic approach with the finite element method. J Oral Rehabil 2008. [DOI: 10.1111/j.1365-2842.2001.00763.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Tanne K. Degenerative changes of articular cartilage in association with mechanical stimuli. JAPANESE DENTAL SCIENCE REVIEW 2008. [DOI: 10.1016/j.jdsr.2007.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Ahn HJ, Paik SK, Choi JK, Kim HJ, Ahn DK, Cho YS, Kim YS, Moon C, Bae YC. Age-related changes in the microarchitecture of collagen fibrils in the articular disc of the rat temporomandibular joint. ACTA ACUST UNITED AC 2008; 70:175-81. [PMID: 18079586 DOI: 10.1679/aohc.70.175] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The microarchitecture of collagen fibrils in the articular disc of the temporomandibular joint (TMJ) plays an important role in dissipating the mechanical load during jaw movement. However, little information is available on its adaptations to the biomechanical environment during development. To address this issue, we analyzed the diameter of collagen fibrils of the articular disc of the rat TMJ with quantitative ultrastructural analysis during postnatal development. The mean diameter of the collagen fibrils significantly increased and the arrangement of the collagen fiber networks became compact during development. Articular discs of suckling rat pups were composed of thin, uniformly sized collagen fibrils (range: 30-60 nm, peak: 40-50 nm). At the age of 4 weeks, thicker collagen fibrils began to appear in articular discs, shortly after weaning (range: 20-70 nm, peak: 40-50 nm). In articular discs of adult rats, collagen fibrils varied widely in diameter, with thick fibrils predominating (range: 10-120 nm, peak: 40-70 nm). These age-related changes in the microarchitecture of collagen fibrils in articular discs may reflect changes in their biomechanical environment during development.
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Affiliation(s)
- Hyung Joon Ahn
- Department of Oral Medicine, Dental Hospital, College of Dentistry, Yonsei University, Seoul, South Korea
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Ueki K, Nakagawa K, Takatsuka S, Yamamoto E, Laskin DM. Comparison of the stress direction on the TMJ in patients with class I, II, and III skeletal relationships. Orthod Craniofac Res 2008; 11:43-50. [DOI: 10.1111/j.1601-6343.2008.00413.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Lemoine JJ, Xia JJ, Andersen CR, Gateno J, Buford W, Liebschner MA. Geometry-Based Algorithm for the Prediction of Nonpathologic Mandibular Movement. J Oral Maxillofac Surg 2007; 65:2411-7. [PMID: 18022462 DOI: 10.1016/j.joms.2007.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Revised: 04/12/2007] [Accepted: 05/30/2007] [Indexed: 10/22/2022]
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22
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Pérez del Palomar A, Doblaré M. An accurate simulation model of anteriorly displaced TMJ discs with and without reduction. Med Eng Phys 2007; 29:216-26. [PMID: 16621657 DOI: 10.1016/j.medengphy.2006.02.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 02/09/2006] [Accepted: 02/16/2006] [Indexed: 11/26/2022]
Abstract
Internal derangement of the temporomandibular joint (TMJ) is defined as an abnormal positional relationship of the disc relative to the mandibular condyle and the glenoid fossa. Among others, the anterior disc displacement is the most common disorder, however its origin and consequences are still unclear. Several finite element simulations of the TMJ have been developed, but none of them has reported dynamic simulations of the disc as a three-dimensional, fiber-reinforced biphasic material under finite deformations, during the opening movement of a pathologic joint affected of an anterior displacement of the disc with and without reduction, using a realistic geometry of the ligaments in the joint. The aim of the work presented here was to compare the stress distribution in the healthy joint and in two pathologic situations, one joint affected of an anterior disc displacement with reduction (ADDWR) and one without reduction (ADDWOR) during an opening movement of the mouth. It was found that, while in the healthy disc the highest compressive stresses were located in the intermediate zone, in the pathologic joints the maximum compressive stresses were located in the posterior band both in the ADDWOR case and in the ADDWR before the reduction. Moreover, although the final stress distribution in the ADDWR was similar to that in the healthy case, the collateral ligaments supported higher stresses, a fact that could lead to degeneration of these components and subsequently to the total anterior displacement of the disc. Finally, the results suggest that an anterior displacement of the disc would lead to higher compressive and tangential stresses in the posterior band of the disc than in the healthy one, and as a consequence, to possible perforations in that zone of the disc which would modify its geometry if no treatment is applied.
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Affiliation(s)
- A Pérez del Palomar
- Group of Structural Mechanics and Materials Modelling, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain.
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Hirose M, Tanaka E, Tanaka M, Fujita R, Kuroda Y, Yamano E, van Eijden TMGJ, Tanne K. Three-dimensional finite-element model of the human temporomandibular joint disc during prolonged clenching. Eur J Oral Sci 2006; 114:441-8. [PMID: 17026512 DOI: 10.1111/j.1600-0722.2006.00389.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the temporomandibular joint (TMJ), overloading induced by prolonged clenching appears to be important in the cascade of events leading to disc displacement. In this study, the effect of disc displacement on joint stresses during prolonged clenching was studied. For this purpose, finite-element models of the TMJ, with and without disc displacement, were used. Muscle forces were used as a loading condition for stress analysis during a time-period of 10 min. The TMJ disc and connective tissue were characterized as a linear viscoelastic material. In the asymptomatic model, large stresses were found in the central and lateral part of the disc through clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 min of clenching. In the symptomatic model, large stresses were observed in the posterior part of the disc and in the retrodiscal tissue, and the stress level was kept constant through clenching. This indicates that during prolonged clenching the disc functions well in the asymptomatic joint, meanwhile the retrodiscal tissue in the symptomatic joint is subject to excessive stress. As this structure is less suitable for bearing large stresses, tissue damage may occur. In addition, storage of excessive strain energy might lead to breakage of the tissue.
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Affiliation(s)
- Miho Hirose
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan
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24
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Scapino RP, Obrez A, Greising D. Organization and function of the collagen fiber system in the human temporomandibular joint disk and its attachments. Cells Tissues Organs 2006; 182:201-25. [PMID: 16914922 DOI: 10.1159/000093969] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2006] [Indexed: 11/19/2022] Open
Abstract
The collagen fiber organization in the anterior band (AB), intermediate zone (IZ) and posterior band (PB) of the disk of the human jaw joint disk and in its attachments was studied under the polarizing microscope. Observations were made on serially sectioned joints (n = 6) and three sets of disk samples sectioned along mutually perpendicular planes (n = 21). The collagen fiber bundles in all disk regions branch and join or are decussated with other bundles. The fibers of the IZ were oriented generally parallel to the disk surfaces. Most of these fibers extend into the AB and PB where they either join with transverse or vertically oriented fiber groups or pass through the bands into the disk attachments. The lateral branching/decussation angles of fibers in the IZ and adjacent regions of the AB and PB were measured in the central region of four disks. The mean angle for all regions was 28 +/- 13 degrees . The mean angles in the region transitional between the IZ and AB and in the anterior region of the IZ were significantly greater than those in the posterior part of the IZ (p = 0.001 and 0.050 for the two comparisons). The large caliber, vertically oriented fibers in the AB, IZ and PB were counted in nine specimens. Disk dimensions were also measured in these specimens. The vertically and transversely oriented bundles were more frequent in the band regions. The number of vertically oriented fiber bundles varied within and between the disk bands. Vertical fiber number in the AB was greater laterally than medially (p = 0.04). In the PB the fiber number was greater than in either the AB or IZ (p = 0.000 for both comparisons) and within the PB itself the fiber number was greater in its thicker, medial half (p = 0.014). The fiber number in the AB and IZ was not different. The thickness of the AB, IZ and PB and disk length was measured in sections located laterally, centrally and medially. No difference in disk length was found across these planes. Statistically significant differences were found in regional disk thickness. In all of the mediolateral planes, the AB and PB were thicker than the IZ and the PB was thicker than the AB (p = 0.000 for all comparisons). The IZ was thicker medially than laterally (p = 0.034). The PB was thicker centrally and medially than laterally (p = 0.002 and 0.001, respectively). PB thickness in its central and medial regions was not different. The findings, combined with other evidence, suggest that the fiber system of the disk serves a stress distribution function and that within the AB and PB, the regions containing the greatest number of vertical fibers may also be the sites of greatest compressive stress during jaw function.
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Affiliation(s)
- Robert P Scapino
- Department of Oral Biology, University of Illinois, Chicago, 60612, USA.
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Pérez del Palomar A, Doblaré M. Anterior displacement of the TMJ disk: repositioning of the disk using a Mitek system. A 3D finite element study. J Biomech Eng 2006; 128:663-73. [PMID: 16995752 DOI: 10.1115/1.2246238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper the behaviors of the temporomandibular joint (TMJ) with an anteriorly displaced disk without reduction and with a surgically repositioned one were compared with the response of a healthy disk during jaw opening. The movement of each joint was obtained imposing the same opening path between incisors and assuming that the movement of the condyle is determined by the passive action of the masticatory muscles and the restrictions imposed by the articulating surfaces and the ligaments. A fiber-reinforced porohyperelastic model was used to simulate the behavior of the articular disk. The influence of the friction coefficient in the diseased joint was also analyzed, finding that the final displacement of the complex condyle-disk was smaller as the friction coefficient increased. On the other hand, its displacement in the repositioned joint was different than in the healthy case because the artificial sutures used in the surgery do not fully stabilize the disk posteriorly as the retrodiscal tissue does. The stress response of the disk changed in both pathologic cases: in the displaced joint the highest stresses moved from the intermediate zone (healthy case) to the posterior band, and in the reconstructed one the most loaded zone moved posteriorly at total opening. Besides, local stress concentrations appeared in the neighborhood of the artificial sutures and therefore damage of the disk and releasing of the sutures might be possible postoperatively.
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Affiliation(s)
- A Pérez del Palomar
- Group of Structural Mechanics and Materials Modeling, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain
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26
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Ueki K, Nakagawa K, Takatsuka S, Yamamoto E. The change of stress distribution on the condyle after mandibular setback surgery. Eur J Orthod 2006; 28:433-9. [PMID: 16679326 DOI: 10.1093/ejo/cjl003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The rigid-body spring model (RBSM) theory was incorporated into a model as a discrete method for analysing problems of limit, such as the stress distribution on the condyle. The purpose of this study was to evaluate the two-dimensional RBSM for determining stress on the temporomandibular joint (TMJ) in patients after orthognathic surgery. Thirty-two patients (five males and 27 females, mean age 21.4 +/- 4.9 years) with mandibular prognathism underwent bilateral sagittal split ramus osteotomy (SSRO) and setback; 48 subjects were recruited as controls. Anatomical landmarks were traced from pre- and post-operative lateral cephalograms and the information was processed using the Fortran analysis program. The force vector on the condyle, its degree, its direction, and the displacement co-ordinates (x, y) and rotation (theta) at the gonial angle were calculated. When muscular power was assumed to be 1, the post-operative degree of the force vector was higher than the pre-operative value (P < 0.05). The X co-ordinate, x, and rotation, theta, of the displacement vector in the pre-operative patients with mandibular prognathism were significantly higher than those in the control subjects (P < 0.05). There were still significant differences between the displacement values post-operatively between the patients and controls (P < 0.05). The results suggest that the degree and direction of the force vector and the resulting displacement co-ordinates can be used as parameters in a surgical model. The RBSM may also be useful in evaluating the pre- and post-operative skeletal morphology of jaw deformities.
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Affiliation(s)
- Koichiro Ueki
- Department of Oral and Maxillofacial Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8941, Japan.
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Deschner J, Rath-Deschner B, Agarwal S. Regulation of matrix metalloproteinase expression by dynamic tensile strain in rat fibrochondrocytes. Osteoarthritis Cartilage 2006; 14:264-72. [PMID: 16290189 PMCID: PMC4948984 DOI: 10.1016/j.joca.2005.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Accepted: 09/14/2005] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We sought to determine the molecular basis for the anticatabolic effects of mechanical signals on fibrocartilage cells by studying the expression of a variety of matrix metalloproteinases (MMPs). Furthermore, we examined whether the effects of biomechanical strain on MMP gene expression are sustained. METHODS Fibrochondrocytes from temporomandibular joint (TMJ) discs were exposed to dynamic tensile strain for various time intervals in the presence of interleukin (IL)-1beta. The regulation of the messenger RNA (mRNA) expression and synthesis of MMPs and tissue inhibitors of MMPs (TIMPs) were examined by end-point and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) as well as Western blot analysis. RESULTS Fibrochondrocytes expressed mRNA for MMP-2, -3, -7, -8, -9, -11, -13, -14, -16, -17, and -19 as well as TIMP-1, -2, and -3, IL-1beta induced a significant (P<0.05) upregulation of mRNA for MMP-3, -7, -8, -9, -13, -16, -17, and -19. The IL-1beta-stimulated upregulation of these MMPs was significantly (P<0.05) abrogated by dynamic tensile strain. However, MMP-2, -11, -14, and TIMPs were not affected by either IL-1beta or tensile strain. Biomechanical strain also inhibited the IL-1beta-stimulated protein synthesis of MMP-3, -7, -8, -9, -13, -16, and -17. Application of mechanical strain for various time intervals during a 24-h incubation with IL-1beta showed that the suppressive effects of mechanical signals are sustained. CONCLUSIONS The data provide evidence that biomechanical signals can downregulate the catabolic activity of fibrocartilage cells in an inflammatory environment by inhibiting the expression of a variety of MMPs. Furthermore, the matrix-protective effects of biomechanical signals are sustained even in an inflammatory environment.
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Affiliation(s)
| | | | - S. Agarwal
- Address correspondence and reprint requests to: Dr Sudha Agarwal, Ph.D., The Ohio State University, Oral Biology and Orthopedics, 4171 Postle Hall, 305 West 12th Avenue, Columbus, OH 43210, USA. Tel: 1-614-688-5935; Fax: 1-614-247-7475;
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Pérez del Palomar A, Doblaré M. The effect of collagen reinforcement in the behaviour of the temporomandibular joint disc. J Biomech 2006; 39:1075-85. [PMID: 16549097 DOI: 10.1016/j.jbiomech.2005.02.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Accepted: 02/15/2005] [Indexed: 11/16/2022]
Abstract
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.
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Affiliation(s)
- A Pérez del Palomar
- Group of Structural Mechanics and Material Modelling, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Maria de Luna, 3, Zaragoza 50018, Spain
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29
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Pérez Del Palomar A, Doblaré M. Finite element analysis of the temporomandibular joint during lateral excursions of the mandible. J Biomech 2006; 39:2153-63. [PMID: 16125714 DOI: 10.1016/j.jbiomech.2005.06.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Accepted: 06/22/2005] [Indexed: 11/28/2022]
Abstract
One of the most significant characteristics of the temporomandibular joint (TMJ) is that it is in fact composed of two joints. Several finite element simulations of the TMJ have been developed but none of them analysed the different responses of its two sides during nonsymmetrical movement. In this paper, a lateral excursion of the mandible was introduced and the biomechanical behaviour of both sides was studied. A three-dimensional finite element model of the joint comprising the bone components, both articular discs, and the temporomandibular ligaments was used. A fibre-reinforced porohyperelastic model was introduced to simulate the behaviour of the articular discs, taking into account the orientation of the fibres in each zone of these cartilage components. The mandible movement during its lateral excursion was introduced as the loading condition in the analysis. As a consequence of the movement asymmetry, the discs were subjected to different load distributions. It was observed that the maximal shear stresses were located in the lateral zone of both discs and that the lateral attachment of the ipsilateral condyle-disc complex suffered a large distortion, due to the compression of this disc against the inferior surface of the temporal bone. These results may be related with possible consequences of a common disorder called bruxism. Although it would be necessary to perform an exhaustive analysis of this disorder, including the contact forces between the teeth during grinding, it could be suggested that a continuous lateral movement of the jaw may lead to perforations of both discs in their lateral part and may damage the lateral attachments of the disc to the condyle.
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Affiliation(s)
- A Pérez Del Palomar
- Group of Structural Mechanics and Material Modeling, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain
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30
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del Palomar AP, Doblaré M. 3D Finite Element Simulation of the Opening Movement of the Mandible in Healthy and Pathologic Situations. J Biomech Eng 2005; 128:242-9. [PMID: 16524337 DOI: 10.1115/1.2165697] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
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.
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Affiliation(s)
- A Pérez del Palomar
- Group of Structural Mechanics Materials Modeling, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain
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31
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Ueki K, Nakagawa K, Marukawa K, Takatsuka S, Yamamoto E. The relationship between temporomandibular joint disc morphology and stress angulation in skeletal Class III patients. Eur J Orthod 2005; 27:501-6. [PMID: 16024561 DOI: 10.1093/ejo/cji029] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The aim of this study was to examine the relationship between disc position and stress direction on the condyle by means of stress analysis using the rigid body spring model (RBSM) theory. The material consisted of 88 joints of 44 Class III dentofacial deformity patients, divided into symmetry and asymmetry groups on the basis of the Mx-Md midline position. The asymmetry group was identified by comparison with a reference midline vertical plane passing through a plane from ANS to Me. Asymmetry was diagnosed when the angle between these two planes was greater than 3 degrees. The geometry of the stress analysis model was based on sagittal tomography of the subject. The first molar, gonial angle, and the most anterior, superior, and posterior points on the condyle were plotted on a computer display, and stress angulation on the condyles was calculated with the RBSM program. In addition to anterior displacement with or without reduction, three types of disc position could be identified using magnetic resonance imaging (MRI): anterior, fully covered and posterior. In the asymmetric group, stress angulation was significantly higher (P < 0.05) at the deviation side compared with the non-deviation side. There was also a significant correlation between disc position and stress angulation (P < 0.05). In the asymmetry group, regression analysis indicated a significant correlation (P < 0.001) between the difference in stress angulation (between the deviation side and the non-deviation side) and the degree of asymmetry (measured by the angle of asymmetry). This study demonstrated that temporomandibular joint (TMJ) stress was associated with TMJ morphology in Class III patients whether or not they were asymmetric.
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Affiliation(s)
- Koichiro Ueki
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kanazawa University, Japan.
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Lemoine JJ, Xia JJ, Gateno J, Liebschner MAK. Radiographic Analysis for Jaw Motion Normalization. J Oral Maxillofac Surg 2005; 63:961-7. [PMID: 16003623 DOI: 10.1016/j.joms.2005.03.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE This study incorporated 3 objectives: 1 ) to evaluate the physical location of the center of rotation as determined by a custom mathematical algorithm, 2 ) to identify and compare the geometric center of the condylar head in radiographs with the calculated center of rotation, and 3 ) to determine whether a correlation exists between jaw motion characteristics and the mandibular geometry of the subject. MATERIALS AND METHODS Lateral cephalometric radiographs of 9 subjects who underwent motion path analysis were obtained. The determined center of rotation of each mandible was calculated through a custom algorithm and recorded on the radiograph. Circular templates were used to determine the geometric center of the condyle for comparisons. Finally, measurements of 4 geometric jaw parameters were made and compared with motion characteristics to investigate whether mandibular geometry can be correlated to motion parameters. RESULTS All calculated centers of rotation were found to lie in the condylar head of the mandible. The average difference between the calculated center of rotation and geometric center of the condylar head was 2.87 mm (SD, 1.69 mm). In addition, correlations were found linking the length of the mandibular rotational arm to the rotational and translational motions. However, there was no correlation found with the other geometric mandibular parameters. CONCLUSIONS Analysis of mandibular motion allows for an accurate determination of the center of rotation. Previously identified characteristic motion exists in terms of primary rotation, followed by translation of the mandible with rotation. The magnitude of each phase differs between subjects. This study points to a natural mechanism of mandibular opening as the amount of rotation increased for longer rotational arms and amount of translation increased for shorter ones, serving to lessen the disparity in the opening amounts among individuals.
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Affiliation(s)
- Jeremy J Lemoine
- Department of Bioengineering, Rice University, Houston, TX 77251, USA
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Kofod T, Cattaneo PM, Dalstra M, Melsen B. Three-Dimensional Finite Element Analysis of the Mandible and Temporomandibular Joint During Vertical Ramus Elongation by Distraction Osteogenesis. J Craniofac Surg 2005; 16:586-93. [PMID: 16077302 DOI: 10.1097/01.scs.0000157305.60505.b5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Distraction osteogenesis has been accepted as an alternative treatment modality for hypoplastic mandibles. Knowledge about the changes occurring in the temporomandibular joint region during mandibular distraction osteogenesis is, however, limited and controversial. Stress distribution in the temporomandibular joint region during unilateral vertical mandibular ramus distraction was studied using a finite element model. The finite element model was based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the temporomandibular joint and mandible was analyzed quantitatively at different intervals of the vertical mandibular ramus elongation. During the distraction phase, the condyles, articular disks, and glenoid fossa regions were loaded with a differentiated stress pattern. The affected right condyle, disk, and fossa were submitted to increasing loads with increasing elongation compared with the contralateral temporomandibular joint. Loading on the unaffected left side shifted posteriorly and slightly laterally, because the left condyle was the center of rotation. The loading of the temporomandibular joint regions was low during the active distraction phase, although local areas were subjected to elevated peak stresses.
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Affiliation(s)
- Thomas Kofod
- Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Nørrebrogade 44, Bygn. 9D, 8000 Aarhus C, Denmark.
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Cattaneo PM, Kofod T, Dalstra M, Melsen B. Using the finite element method to model the biomechanics of the asymmetric mandible before, during and after skeletal correction by distraction osteogenesis. Comput Methods Biomech Biomed Engin 2005; 8:157-65. [PMID: 16214710 DOI: 10.1080/10255840500237953] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
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.
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Affiliation(s)
- Paolo M Cattaneo
- Aarhus University, Department of Orthodontics, School of Dentistry, Aarhus, Denmark.
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35
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Kofod T, Cattaneo PM, Melsen B. Three-Dimensional Finite Element Analysis of the Mandible and Temporomandibular Joint on Simulated Occlusal Forces before and after Vertical Ramus Elongation by Distraction Osteogenesis. J Craniofac Surg 2005; 16:421-9. [PMID: 15915108 DOI: 10.1097/01.scs.0000171969.32110.ab] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Distraction osteogenesis has recently become a mainstay for treatment of mandibular hypoplasia. Thorough knowledge about changes in the temporomandibular joint (TMJ) and the surrounding parts of the mandible and the skull after mandibular distraction is still lacking. The purpose of the current study was to investigate the stress distribution in the mandible and the TMJ before and after skeletal correction by intraoral unilateral vertical mandibular ramus distraction, using a finite element (FE) model. The FE models were based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the mandible and TMJ before and after skeletal correction by 15 mm of vertical distraction of the mandibular ramus was analyzed quantitatively and compared during centric occlusion. Before the distraction osteogenesis treatment, the condyles, articular discs, and glenoid fossa regions are loaded with a different stress pattern. The affected right condyle, disc, and fossa are loaded diffusely and externally in comparison with the anterior and with centralized loading on the normal left side. After unilateral mandibular distraction osteogenesis, the load became more centric and symmetrical. The results suggest that correction of the mandibular deformity by distraction osteogenesis tends to normalize the stress patterns in the TMJ.
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Affiliation(s)
- Thomas Kofod
- Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Aarhus, Denmark.
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36
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Allen KD, Athanasiou KA. Viscoelastic characterization of the porcine temporomandibular joint disc under unconfined compression. J Biomech 2005; 39:312-22. [PMID: 16321633 DOI: 10.1016/j.jbiomech.2004.11.012] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Accepted: 11/15/2004] [Indexed: 11/30/2022]
Abstract
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.
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Affiliation(s)
- Kyle D Allen
- Department of Bioengineering, Rice University, MS142, E-100-A George R. Brown Hall, P.O. Box 1892, Houston, TX 77251-1892, USA.
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Donzelli PS, Gallo LM, Spilker RL, Palla S. Biphasic finite element simulation of the TMJ disc from in vivo kinematic and geometric measurements. J Biomech 2004; 37:1787-91. [PMID: 15388322 DOI: 10.1016/j.jbiomech.2004.01.029] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2004] [Indexed: 10/26/2022]
Abstract
Understanding the biomechanical nature of the degeneration of the temporomandibular joint requires a coupling between experimental measurements and numerical simulation. In this study, geometry measured from MRI, and motion obtained from a specially designed optoelectronic system are fed into a three-dimensional biphasic finite element analysis to generate the spatial and temporal mechanical response of the disc. This study demonstrates how this coupling can effectively predict the biomechanical response of the temporomandibular joint disc to physiological loading. For small jaw opening movements, asymmetries in the load of the disc are found, with especially higher shear stresses in the lateral portion.
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Affiliation(s)
- Peter S Donzelli
- Department of Biomedical Engineering and Scientific Computation Research Center, JEC 7049, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
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Radu M, Marandici M, Hottel TL. The effect of clenching on condylar position: A vector analysis model. J Prosthet Dent 2004; 91:171-9. [PMID: 14970764 DOI: 10.1016/j.prosdent.2003.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
STATEMENT OF THE PROBLEM Clinicians often disagree about the acceptable position of the condyle in the articular fossa. Agreement as to what position the condyle-disk assembly assumes on the articular eminence while subjected to the forces of the elevator muscles of the mandible is important. PURPOSE This simulation study investigated the position of the condyle-disk assembly on the articular eminence while subjected to the forces of the elevator muscles of the mandible during clenching. MATERIAL AND METHODS Using the 2 conditions of static equilibrium, a vector analysis of a 2-dimensional model of the temporomandibular joint was developed. The dynamics of the condyle-disk assembly during muscle loading were analyzed. The vector sum of the masticatory muscle forces was determined by assuming that the maximum force developed by each contributing muscle was proportional with the physiologic cross section of the muscle. The effect of the resultant force vector of the combined muscle action applied to the condyle was analyzed for the orthogonal and acute angle situations. RESULTS When the vector sum was orthogonal on the eminence, the condyle was in stable equilibrium. The stable equilibrium was found in the anterior-superior position in the fossa. When the vector sum was at an acute angle to the eminence, the condyle was subject to a translation force that displaced it into the anterior-superior equilibrium position. CONCLUSION Within the limitation of this study, vector analysis suggested that the anterior-superior position of the condyle-disk assembly on the eminence was the most stable equilibrium position. All other tested positions of the condyle were less stable and maintained at the expense of other structures.
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Affiliation(s)
- Michael Radu
- Department of Restorative Dentistry, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA.
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39
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Tanaka E, Kikuzaki M, Hanaoka K, Tanaka M, Sasaki A, Kawai N, Ishino Y, Takeuchi M, Tanne K. Dynamic compressive properties of porcine temporomandibular joint disc. Eur J Oral Sci 2003; 111:434-9. [PMID: 12974689 DOI: 10.1034/j.1600-0722.2003.00066.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study aimed to evaluate the effect of the strain frequency and amplitude on the compressive properties of the porcine temporomandibular joint disc and to determine the time-dependent changes associated with energy dissipation. Seven discs were used for compressive cycle tests, including various frequencies and magnitudes of compressive strain. Each experiment consisted of 25 cycles of loading and unloading. Hysteresis and the instantaneous and steady moduli were calculated. All specimens showed a clear hysteresis and repeatable stress-strain relationships within 19 cycles. The hysteresis at the initial cycle ranged between 35% and 62%, and gradually decreased in subsequent cycles. The instantaneous modulus became larger when the strain frequency and the strain amplitude increased. The steady modulus was approximately one-third of the instantaneous one. It was concluded that the disc has an energy-dissipating function during dynamic compression.
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Affiliation(s)
- Eiji Tanaka
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Kasumi, Hiroshima, Japan.
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40
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Affiliation(s)
- Jan Harm Koolstra
- Department of Functional Anatomy-ACTA, Meibergdreef 15, 1105 AZ Amsterdam, the Netherlands.
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Tanaka E, van Eijden T. Biomechanical behavior of the temporomandibular joint disc. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2003; 14:138-50. [PMID: 12764076 DOI: 10.1177/154411130301400207] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The temporomandibular joint (TMJ) disc consists mainly of collagen fibers and proteoglycans constrained in the interstices of the collagen fiber mesh. This construction results in a viscoelastic response of the disc to loading and enables the disc to play an important role as a stress absorber during function. The viscoelastic properties depend on the direction (tension, compression, and shear) and the type of the applied loading (static and dynamic). The compressive elastic modulus of the disc is smaller than its tensile one because the elasticity of the disc is more dependent on the collagen fibers than on the proteoglycans. When dynamic loading occurs, the disc is likely to behave less stiffly than under static loading because of the difference of fluid flow through and out of the disc during loading. In addition, the mechanical properties change as a result of various intrinsic and extrinsic factors in life such as aging, trauma, and pathology. Information about the viscoelastic behavior of the disc is required for its function to be understood and, for instance, for a suitable TMJ replacement device to be constructed. In this review, the biomechanical behavior of the disc in response to different loading conditions is discussed.
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Affiliation(s)
- Eiji Tanaka
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Japan.
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Hu K, Qiguo R, Fang J, Mao JJ. Effects of condylar fibrocartilage on the biomechanical loading of the human temporomandibular joint in a three-dimensional, nonlinear finite element model. Med Eng Phys 2003; 25:107-13. [PMID: 12538065 DOI: 10.1016/s1350-4533(02)00191-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study was undertaken to test a hypothesis that the addition of articular fibrocartilage in the condyle of the temporomandibular joint reduces three-dimensional stress distribution in the condyle, the disc and articular eminence. A three-dimensional, nonlinear finite-element model was developed for analysis of joint loading before and after the addition of condylar fibrocartilage to the osseous mandibular condyle reconstructed from spiral computer topography data. In the model, each of the disc, condyle and articular eminence was arbitrarily divided into five regions: the anterior, posterior, medial, lateral and central. Von Mises stresses that in virtually all regions of the disc, condyle and articular eminence became lower after the addition of condylar fibrocartilage. Especially remarkable was the approximately four-fold reduction in von Mises stresses in the anterior, central and medial regions of the mandibular condyle. In comparison, only slight to moderate stress reductions occurred in the disc and articular eminence, suggesting that condylar fibrocartilage absorbs considerable stresses and likely dampens more loads than the disc and articular eminence. The mandibular condyle demonstrated the largest total displacement in all directions after the addition of articular fibrocartilage, followed by the disc and articular eminence. We conclude that the addition of articular fibrocartilage primarily reduces loading of the mandibular condyle, rather than the disc and articular eminence. These findings lead to a hypothesis that the mandibular condyle more likely functions as a shock absorber than the disc.
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Affiliation(s)
- Kai Hu
- Tissue Engineering Laboratory, Department of Orthodontics, University of Illinois at Chicago, 60612, USA
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Beek M, Koolstra JH, van Eijden TMGJ. Human temporomandibular joint disc cartilage as a poroelastic material. Clin Biomech (Bristol, Avon) 2003; 18:69-76. [PMID: 12527249 DOI: 10.1016/s0268-0033(02)00135-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The hypothesis was tested that a poroelastic material model is potentially able to describe the mechanical behavior of cartilaginous tissues in dynamic indentation experiments.Design. This hypothesis was tested by comparing the results from model predictions with results obtained from cyclic indentation experiments. BACKGROUND The characteristics of cartilaginous tissues in general and of the temporomandibular joint disc in particular are generally identified by static confined or unconfined indentation experiments, while under physiologic circumstances these tissues are mostly loaded dynamically. METHODS Dynamic indentation experiments were simulated using an axisymmetric finite element model. The results from the simulations were qualitatively compared with the experiments. RESULTS The simulations showed several similarities with the experiments when the solid matrix was assumed to be hyperelastic. Both the maximum stress and the amount of energy dissipated decreased in each subsequent cycle. Furthermore, a similar dependency on the indentation frequency and amplitude was found. CONCLUSIONS This qualitative study showed that a poroelastic material model can describe the dynamic behavior of the temporomandibular joint disc, provided that the solid matrix is modeled as hyperelastic. RELEVANCE Temporomandibular disorders are presumably related to joint load distributions. Besides large static, dynamic loads are considered as a risk factor for cartilaginous wear. Dynamical loads, however, are also considered to stimulate the biosynthetic activity of cartilaginous tissues. Biomechanical analysis can be applied to estimate nonmeasurable joint loads. This enables to understand the underlying mechanisms of temporomandibular disorders, necessary to develop methods to prevent, diagnose and cure joint disorders. The present study shows that a poroelastic material model can be applied successfully to model the dynamical behavior of the temporomandibular joint disc in such analyses.
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Affiliation(s)
- M Beek
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
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Beek M, Koolstra JH, van Ruijven LJ, van Eijden TM. Three-dimensional finite element analysis of the cartilaginous structures in the human temporomandibular joint. J Dent Res 2001; 80:1913-8. [PMID: 11706951 DOI: 10.1177/00220345010800101001] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
While the movability of the human temporomandibular joint is great, the strains and stresses in the cartilaginous structures might largely depend on the position of the mandible with respect to the skull. This hypothesis was investigated by means of static three-dimensional finite element simulations involving different habitual condylar positions. Furthermore, the influence of several model parameters was examined by sensitivity analyses. The results indicated that the disc moved together with the condyle in the anterior direction without the presence of ligaments and the lateral pterygoid muscle. By adapting its shape to the changing geometry of the articular surfaces, the disc prevented small contact areas and thus local peak loading. In a jaw-closed configuration, the influence of 30 degrees variations of the loading direction was negligible. The load distribution capability of the disc appeared to be proportional to its elasticity and was enhanced by the fibrocartilage layers on the articular surfaces.
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Affiliation(s)
- M Beek
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), The Netherlands
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45
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Tanaka E, Rodrigo DP, Tanaka M, Kawaguchi A, Shibazaki T, Tanne K. Stress analysis in the TMJ during jaw opening by use of a three-dimensional finite element model based on magnetic resonance images. Int J Oral Maxillofac Surg 2001; 30:421-30. [PMID: 11720045 DOI: 10.1054/ijom.2001.0132] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study was designed to investigate temporomandibular joint (TMJ) stress distribution during mouth opening using a finite element (FE) model of an individual TMJ based on magnetic resonance (MR) images. A dry skull with a silicon disk was used to test the three-dimensional reconstruction procedure, and showed enough accuracy and reproducibility in linear dimensions and disk volume for the following FE modelling for stress analysis in the TMJ. From an individual FE analysis of a normal subject, relatively high stresses were observed in the anterior and posterior regions of the disk during mouth opening, and furthermore, the superior boundary contacting with the glenoid fossa exhibited lower stresses than those on the inferior boundary facing the condyle. During transmission of stress through the disk, mechanical stress may be reduced by the stress redistribution function of the disk.
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Affiliation(s)
- E Tanaka
- Department of Orthodontics, Hiroshima University Faculty of Dentistry, Japan.
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Devocht JW, Goel VK, Zeitler DL, Lew D. Experimental validation of a finite element model of the temporomandibular joint. J Oral Maxillofac Surg 2001; 59:775-8. [PMID: 11429739 DOI: 10.1053/joms.2001.24292] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE A 2-dimensional finite model of the temporomandibular joint (TMJ) was previously developed to provide a way of studying the specific roles of individual components as well as the overall dynamics of joint motion. This study was undertaken to show that the previously reported finite element model provides results that are consistent with the experimentally obtained results. MATERIALS AND METHODS The upper compartment of a TMJ of a fresh cadaver specimen was exposed to allow the insertion of a small strip of pressure-sensitive film. Measured loads were applied to the chin and angle of the mandible, pressing the condyle into the glenoid fossa. The resulting stresses in the joint stained the film, providing a way to determine their magnitude. Similar loads were applied to the finite element model and the stresses in the TMJ were mathematically calculated. RESULTS Experimental results were successfully obtained in 4 separate attempts, recording maximum stresses of 5.6, 8.6, 6.4, and 9.9 MPa (megapascals), respectively. The corresponding finite element model predictions were 7.3, 6.9, 6.4, and 8.2 MPa, respectively. CONCLUSIONS This study indicates that the results of the previously reported finite element model of the TMJ provide a reasonable approximation of the actual physical situation.
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Affiliation(s)
- J W Devocht
- Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA.
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47
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Beek M, Aarnts MP, Koolstra JH, Feilzer AJ, van Eijden TM. Dynamic properties of the human temporomandibular joint disc. J Dent Res 2001; 80:876-80. [PMID: 11379888 DOI: 10.1177/00220345010800030601] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The cartilaginous intra-articular disc of the human temporomandibular joint shows clear anteroposterior variations in its morphology. However, anteroposterior variations in its tissue behavior have not been investigated thoroughly. To test the hypothesis that the mechanical properties of fresh human temporomandibular joint discs vary in anteroposterior direction, we performed dynamic indentation tests at three anteroposteriorly different locations. The disc showed strong viscoelastic behavior dependent on the amplitude and frequency of the indentation, the location, and time. The resistance against deformations and the shock absorbing capabilities were larger in the intermediate zone than in regions located more anteriorly and posteriorly. Because several studies have predicted that the intermediate zone is the predominantly loaded region of the disc, it can be concluded that the topological variations in its tissue behavior enable the disc to combine the functions of load distribution and shock absorption effectively.
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Affiliation(s)
- M Beek
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), The Netherlands.
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48
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Carmeli E, Sheklow SL, Bloomenfeld I. Comparative Study of Repositioning Splint Therapy and Passive Manual Range of Motion Techniques for Anterior Displaced Temporomandibular Discs with Unstable Excursive Reduction. Physiotherapy 2001. [DOI: 10.1016/s0031-9406(05)61189-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Beek M, Koolstra JH, van Ruijven LJ, van Eijden TM. Three-dimensional finite element analysis of the human temporomandibular joint disc. J Biomech 2000; 33:307-16. [PMID: 10673114 DOI: 10.1016/s0021-9290(99)00168-2] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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.
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Affiliation(s)
- M Beek
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), The Netherlands.
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Iizuka T, Lädrach K, Geering AH, Raveh J. Open reduction without fixation of dislocated condylar process fractures: long-term clinical and radiologic analysis. J Oral Maxillofac Surg 1998; 56:553-61; discussion 561-2. [PMID: 9590337 DOI: 10.1016/s0278-2391(98)90450-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE This study evaluates the long-term results of open reduction without fixation for displaced fractures of the condylar process. PATIENTS AND METHODS Clinical and radiologic examinations were performed on 27 patients with 29 operated joints an average of 6.7 years postoperatively. The postoperative result was evaluated on the basis of occlusal and joint function, as well as radiographic assessment of condylar changes. RESULTS Clinically, satisfactory results were achieved. Radiologically, despite correct intraoperative alignment of the fractured segments, a slight medial deviation of the condylar process was found on the posteroanterior radiograph. However, in only two cases was a 20-degree deviation observed. On final follow-up, 48% of the cases had a normal condylar configuration radiologically, and in the remaining cases, normal function was established even though there were condylar changes. Fully exposed and devascularized condylar processes generally showed more severe changes than those in which partial vascularization was maintained. CONCLUSION The surgical management described enables a satisfactory outcome to be achieved with dislocated condylar process fractures.
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Affiliation(s)
- T Iizuka
- Department of Cranio-Maxillofacial Surgery, School of Dental Medicine, University Hospital of Bern (Inselspital), Switzerland
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