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Anatomy and Embryology of the Mouth and Dentition
Published in John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford, Head & Neck Surgery Plastic Surgery, 2018
The articular disc (meniscus) is of a dense, fibrous consistency and is moulded to the bony joint surfaces above and below. Blood vessels are only evident at the periphery of the articular disc, the bulk of its central part being avascular. When viewed in sagittal section, the upper surface of the disc is concavo-convex anteroposteriorly and the lower surface is concave. Viewed superiorly, the articular disc is somewhat rectangular or oval in outline. The overall shape of the articular disc is thought to provide a self-centring mechanism, which automatically acts to maintain its correct relationship to the articular surface of the mandibular condyle during mandibular movements. Whereas some regard the functions of the articular disc as helping to spread the joint forces and to stabilize the condyle, others see its function as primarily destabilizing the condyle and permitting it to move more freely.16
Surgery to the temporomandibular joint
Published in John Dudley Langdon, Mohan Francis Patel, Robert Andrew Ord, Peter Brennan, Operative Oral and Maxillofacial Surgery, 2017
The articular disc plays a pivotal role in the complex mechanics of joint function. Any change in its physical structure, integrity or position may result in pain and joint dysfunction referred to as internal derangement.
The Articulations of the Upper Member
Published in Gene L. Colborn, David B. Lause, Musculoskeletal Anatomy, 2009
Gene L. Colborn, David B. Lause
Identify the articular disk of the radiocarpal joint. Note that the disk separates the head of the ulna from direct articulation with the carpus. Observe that the articular disk binds the styloid process of the ulna with the medial edge of the distal end of the radius.
Biomechanical effects of high acceleration on the temporomandibular joint
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Haotian Luo, Jingheng Shu, Zhan Liu
Differing from the results of the Gy models, there is no significant difference in the stress distributions between the left and right articular disks in the Gx and Gx-low models (Figure 2). In the Gx models, the stress concentrations occurred in the anterior and posterior bands of the both articular discs, and the maximum tensile stress is much higher than the failure stress of these bands (Figure 2C) (1.85 MPa, 1.35 MPa) (Tanaka et al. 1998). In the Gx-low model, the stress concentrations also occurred in the anterior and posterior bands, but the maximum tensile stress was far less than its failure stress (Figure 2C). In general, the intermediate zone of the articular disc is subjected to high pressure (Öberg et al. 1971; Beek et al. 2000). However, the tensile stress in the intermediate zone of the left and right discs of the Gx model increases by 2.07 and 2.12 times compared with the Gx-low model. It intensified the abnormal stress distribution in the intermediate zone. Although the contact regions of the cartilages in the Gx and Gx-low models were the same, the maximum contact stress of the Gx model is greater (increased 186% to 717%) (Figures 3 and 4). Increased contact stress can strengthen the squeezing and friction in the TMJs, which might lead to other symptoms such as osteoarthritis. The results indicated that bilateral TMJs were at risk under high forward acceleration.
Effect of sagittal split ramus osteotomy on stress distribution of temporomandibular joints in patients with mandibular prognathism under symmetric occlusions
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Hedi Ma, Jingheng Shu, Quanyi Wang, Haidong Teng, Zhan Liu
In this study, the surface-to-surface contact discretization method and the small-sliding tracking approach were used. For the tangential behavior, the penalty function was chosen as the friction formulation based on previous studies, and the frictional coefficient of the contact area was considered to be 0.001 ( Liu et al. 2008; Shu et al. 2018). For the normal behavior, the Lagrange multiplier method was chosen as constraint enforcement method (Liu et al. 2008; Shu et al. 2018). Young moduli of the bones (cortical bone, cancellous bone, and teeth) were assigned according to the empirical formulas given in Equations (1)–(3) (Harp et al. 1994; Rho et al. 1995; Kopperdahl et al. 2002). The material properties of the articular disc were assumed to be linearly elastic (Liu et al. 2008). Young moduli of the articular disc was defined as 44.1 MPa (Liu et al. 2008). Poisson ratios of the bones (cortical bone, cancellous bone, and teeth) and the disc were defined as 0.3 and 0.4, respectively (Liu et al. 2008). The modified ten-node quadratic tetrahedron element (C3D10M) was used in the TMJ regions and the four-node linear tetrahedron element (C3D4) was used in the other regions of the models. The average number of nodes and elements for the finite element models were about 30,550 and 87,200 through convergence test. The mesh quality of all the models was checked in ABAQUS. The analysis error of mesh was 0, and the analysis warning of mesh was under 5%.
Preliminary simulation model toward the study of the effects caused by different mandibular advancement devices in OSAS treatment
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Agnese Brunzini, Antonio Gracco, Alida Mazzoli, Marco Mandolini, Steve Manieri, Michele Germani
Next steps focus on the TMJ modelling. Soft tissues such as articular disc and ligaments are not identifiable from CT images. For this reason, the reconstructed surfaces of temporal bone, mandible and teeth are imported in Rhinoceros 3D v.5.0 by McNeel Inc., a commercial 3D modelling tool, where soft elements are designed according to anatomical atlas and medical literature. The articular disc has been modelled following the method proposed by Alkhiary et al. 2012, extracting the upper surface of the condyle toward the glenoid fossa. The result is shown in Figure 1.