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Internal Derangements of the Temporomandibular Joint, Pathological Variations
Published in Niall MH McLeod, Peter A Brennan, 50 Landmark Papers every Oral & Maxillofacial Surgeon Should Know, 2020
Carrol P Saridin, Pieter G Raijmakers
The basic lesion observed was malposition (anterior displacement) and altered structure of the articular disc. There was a near 100% correlation between the presence of disc displacement and the presence of clinical signs and symptoms.
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 temporomandibular (craniomandibular) joint (TMJ) is a synovial joint. It is formed by the mandibular (glenoid) fossa articulating with the mandibular condyle. The TMJ has a number of unusual features: The joint space is divided into two joint cavities (upper and lower) by an intra-articular disc.The articular surfaces are not composed of hyaline cartilage but of fibrous tissue (reflecting the joint’s intramembranous development).A secondary condylar cartilage is present in the head of the condyle until adolescence.Movements of the joint are influenced by the teeth. The shape of the mandibular fossa does not conform exactly to the shape of the mandibular condyle and this may partly explain why the joint cavity is divided by an articular disc into upper and lower compartments (Figure 41.17).6, 13 The TMJ allows both gliding (upper joint compartment) and hinge (lower joint compartment) movements.
The Crucial Role of Craniofacial Growth on Airway, Sleep, and the Temporomandibular Joint
Published in Aruna Bakhru, Nutrition and Integrative Medicine, 2018
Diagnostic studies are designed to rule out other disorders. They may include the use of blood and serum inflammatory markers to rule out autoimmune disorders and vasculitis. Imaging such as panoramic radiograph (a single-cut tomogram of the entire jaw) remains the most useful screening tool. Plain radiographs have been almost completely replaced by computed tomography (CT) for evaluation of bony morphology and pathology of the joint, mandibular ramus, and condyle. Cone-beam maxillofacial CT is a newer and faster technique, with a lower radiation dose, than conventional whole-body CT (Hashimoto et al. 2014). Magnetic resonance imaging (MRI) has replaced other imaging methods for evaluation of soft-tissue abnormalities of the joint and surrounding region. The anatomy of the joint and the position and structure of the intra-articular disk can be accurately visualized both at rest and in motion. MRI allows for analysis of the blood supply and vascularity of the condyle and for detection of pathologic accumulations of fluid within and around the joint. Diagnostic nerve blocks and muscle trigger point injections may in certain cases provide the only method to identify the true genesis of pain (Bell 1990). Thermography imaging techniques measure temperature within the soft tissues of the musculoskeletal system. Temperature changes on the surface of the skin may correlate with underlying pathosis (Biagioni et al. 1996). This method of imaging does not produce ionizing radiation and therefore is extremely safe with no known side effects.
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%.
Association of volume and voxel intensity of the articular disc and lateral pterygoid muscle in migraine patients: a study with magnetic resonance imaging
Published in Acta Odontologica Scandinavica, 2020
Ana Amelia Barbieri, Andre Luiz Ferreira Costa, João Pedro Perez Gomes, Ana Lucia Franco Ricardo, Paulo Henrique Braz-Silva, Sergio Lucio Pereira de Castro Lopes
The articular disc of the TMJ is a fibrocartilaginous structure, which has average dimensions ranging from 1.0 to 1.5 cm in the mid-distal direction and from 0.7 to 0.8 cm in the anterior-posterior direction, being morphologically a biconcave structure with anterior and posterior bands and posterior thickening [31]. All this composition associated with the anatomical conformation of the disc is responsible for its correct congruence with the condyle and temporal structures (i.e. tubercle and articular fossa) during TMJ movements, allowing rotation and translation of the condylar and temporal surfaces and favouring that the disc is always positioned between them [23].
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.