Healing following condylar shave in the monkey temporomandibular joint

Condylar shaves were performed in monkeys, and the reparative process was studied by histologic and autoradiographic techniques. The condylar surface was found to repair mainly with fibrous connective tissue produced by cells derived from the underlying marrow spaces. The residual condylar cartilage did not play a significant role in this process.     

Osteoplasty of the mandibular condyle with preservation of the articular soft tissue cover: comparison of fibrin sealant and sutures for fixation of the articular soft tissue cover in rabbits

Fibrin sealant and sutures were compared for fixation of the articular soft tissue cover after it had been raised in association with osteoplasty of the mandibular condyle. Nine adult rabbits were operated on bilaterally with the use of fibrin sealant on one joint and sutures on the other joint. The rabbits were killed after 3 months. Macroscopic and histologic evaluations of the condyles did not reveal any appreciable differences between the two techniques. Fibrin sealant was, however, technically easier to apply than the sutures. It was concluded that fibrin sealant might be an alternative to sutures for fixation of the articular soft tissue cover after it has been raised in association with osteoplasty of the mandibular condyle.     

Radiographic study of articular remodeling in the temporomandibular joint after condylar fractures

abstract — A radiographic follow-up of the temporomandibular joints in patients with condylar fractures revealed a frequent remodeling both of the condylar head and the glenoid fossa. A double contour of the fossa was the typical radiographic sign of remodeling. The occurrence of double contours was associated with displacement of the condylar head.     

Thickness of the soft tissue layers and the articular disk in the temporomandibular joint

Out of 115 right temporomandibular joints from Swedish subjects aged 1 day to 93 years, 48 joints without any gross sign of arthrosis or deviation in form were examined histologically.

The joint components were cut sagittaly, each into four parts. Histological sections were made of the condyle, the temporal component and of the articular disk. The total thickness of the soft tissue layers was measured in decalcified sections, cut from the medio-central and lateral parts of the condyle and the temporal component and from the medial, medio-central, latero-central and lateral regions of the disk. In the medio-central sections from the condyle and temporal component the thickness of the fibrous connective tissue layer i.e. the surface layer was also registered. The soft tissue layers were thickest in the condyle superiorly, about 0.4–0.5 mm, in the temporal component on the postero-inferior slope of the articular tubercle, about 0.5 mm, and in the disk posteriorly about 2.9 mm. In the roof of the fossa it was only 0.1 mm. The soft tissue layers on the condyle as well as the disk were thinner laterally while the corresponding tissue in the temporal component was thicker laterally. The thickness of the soft tissue layers seem to reflect the growth and functional load to which the joint is exposed.     

Magnetic resonance imaging assessment of temporomandibular joint soft tissue injuries of intracapsular condylar fracture

We evaluated the soft tissue of the temporomandibular joint (TMJ) with magnetic resonance imaging (MRI) after intracapsular condylar fracture. Eighteen consecutive patients (19 TMJ) were diagnosed between 1 January 2010 and 30 October 2011. They were examined using bilateral sagittal and coronal MRI, which were obtained immediately after injury to assess the displacement of the disc, whether there was a tear in capsule or the retrodiscal tissue, and whether there was an effusion in the joint. On the affected side MRI showed disc displacement in 15 of 19, tears in the capsule in 9, and tears in the retrodiscal tissue in 16. All 19 had joint effusions. It also showed 2 joints with abnormalities on the unaffected side. We conclude that MRI is useful for diagnosis and for estimating the amount of damage to the TMJ, and is helpful in planning treatment.     

Thickness of the soft tissue layers and the articular disk in the temporomandibular joint.

Out of 115 right temporomandibular joints from Swedish subjects aged 1 day to 93 years, 48 joints without any gross sign of arthrosis or deviation in form were examined histologically. The joint components were cut sagittaly, each into four parts. Histological sections were made of the condyle, the temporal component and of the articular disk. The total thickness of the soft tissue layers was measured in decalcified sections, cut from the medio-central and lateral parts of the condyle and the temporal component and from the medial, medio-central, latero-central and lateral regions of the disk. In the medio-central sections from the condyle and temporal component the thickness of the fibrous connective tissue layer i.e. the surface layer was also registered. The soft tissue layers were thickest in the condyle superiorly, about 0.4-0.5 mm, in the temporal component on the postero-inferior slope of the articular tubercle, about 0.5 mm, and in the disk posteriorly about 2.9 mm. In the roof of the fossa it was only 0.1 mm. The soft tissue layers on the condyle as well as the disk were thinner laterally while the corresponding tissue in the temporal component was thicker laterally. The thickness of the soft tissue layers seem to reflect the growth and functional load to which the joint is exposed.     

Computed tomography of condylar and articular disk positions within the temporomandibular joint

The computed tomograms of temporomandibular joints in 25 patients (41 joints) were retrospectively evaluated for condylar position and joint space with General Electric computer software. Computed tomography scans of the temporomandibular joint were made in the axial plane with the teeth in centric occlusion, and measurements were made from vertically reformatted images. Interarticular joint spaces were measured anterosuperiorly, superiorly, posterosuperiorly, and posteriorly from the condylar surfaces. This was repeated in five equidistant (3.1 mm) serial sagittal planes across the condyle, beginning and ending, on average, 2.5 mm from the lateral and medial condylar poles. Articular disk positions (anterolateral, anterior, anteromedial, medial, and normal) were correlated with condylar position. Significant differences between disk positions and joint spaces were found most frequently in the anterosuperior and the superior joint interval. When the disk was positioned normally, the anterosuperior joint space was consistent (1.5 to 2.0 mm) across the joint (standard deviation, 0.3 to 0.8 mm). The superior, the posterosuperior, and the posterior joint spaces in the normal joint were greater than the anterosuperior joint space. When the disk was anterior to the condyle, the anterosuperior joint interval was widened. When the disk was medial, the superior joint space was significantly wider than normal across the breadth of the condyle. In those joints in which the disk was anteromedial, there was an absence (0.2 mm) of joint space, and this occurred in all areas of the condyle except in its medial one fourth. In the internally deranged joint, joint space narrowing may be focal in nature.     

Histological and immunohistochemical studies on the articular cartilage after experimental discectomy of the temporomandibular joint in rabbits

Total discectomy was performed experimentally in the rabbit temporomandibular joint (TMJ). In order to evaluate the injury and repair of the articular cartilage of the mandibular condyle after discectomy, both histologic and immunohistochemical observations were made. Immunohistochemical observation by using bromodeoxyuridine (BrdU) and its monoclonal antibody in vivo labelling method was used.
The present study demonstrated that the cartilage on the articular surface of the condyle disappeared at 1 week post-operatively. This defect in the injured articular cartilage was not repaired by the cartilage, but was covered by a fibrous connective tissue at 6 weeks post-operatively, where the condylar recontouring by the adjacent articular cartilage, and flattening and hyperplasia of the condyle were observed. Thus, the cartilaginous repair following discectomy was characterized by the proliferation of the adjacent cartilage to the injured site and osteoblastic formation in the bone marrow at the exposed subchondral bone.     

Discectomy of the temporomandibular joint: an experimental study in monkeys.

Postoperative changes have been observed in the temporomandibular joint (TMJ) after discectomies. Animal models have often shown that interventions in the TMJ may heal uneventfully. Discectomies were performed on 14 Macaca fascicularis and macroscopic and microscopic examination performed after sacrifice of the animals. Two of the animals did not show any apparent macroscopic or microscopic changes. The remaining 12 joints showed minor to major changes. The most serious changes were seen in three joints with fibrous ankylosis and five joints showed marked destruction of the articular cartilage.     

Synovial chondromatosis of the temporomandibular joint with condylar extension

Synovial chondromatosis is a benign disease that rarely affects the temporomandibular joint (TMJ). It can be seen commonly in the superior joint space and presents with various signs and symptoms according to the stage of progression. Sometimes it presents as a large swelling in the preauricular area with or without cranial extension, and the clinical and radiographic findings may be misdiagnosed as other benign or malignant diseases of TMJ. Therefore, we report an uncommon case of synovial chondromatosis presenting as a large preauricular mass arising from the inferior joint space of the TMJ with bony resorption of the mandibular condyle, which mimicked osteochondroma.     

Magnetic resonance imaging findings of temporomandibular joint soft tissue changes in type V and VI condylar injuries.

PURPOSE: The objective of this study was to describe the incidence of acute temporomandibular joint (TMJ) soft tissue lesions associated with the occurrence of type V (high condylar fractures with dislocation) and type VI condylar fractures (condylar head fractures). PATIENTS AND METHODS: The study comprised 11 consecutive patients, who were assigned a diagnosis of a uni- or bilateral type V or type VI condylar fracture. Bilateral sagittal and coronal magnetic resonance (MR) images were obtained immediately after injury to establish the presence or absence of disc disruption, capsular tear, retrodiskal tissue tear, and hemarthrosis. RESULTS: There was 1 condylar fracture site showing signs of disc disruption (16.7%). Tears in the capsule and retrodiscal tissue were found with an incidence of 77% and 71%, respectively, while the incidence of hemarthrosis accounted for 100%. MR imaging failed to show any signs of soft tissue lesions for condylar nonfracture sites. CONCLUSIONS: Type V and type VI condylar fracture sites are associated with a high incidence of injuries to the joint capsule and retrodiscal tissue. Investigation of longitudinal evidence, including risk factors, natural history, and response to treatment appears warranted and necessary.     

Chondrocyte clusters in the condylar cartilage of an ankylosed temporomandibular joint

A complete condyle specimen from a female patient who had temporomandibular joint (TMJ) ankylosis and associated craniofacial deformities was obtained. Abundant chondrocyte clusters were found in the remaining cartilage of the enlarged condyle. The implications of the clusters in this patient are discussed.     

Contributions of temporomandibular articular mechanoreceptors to the control of mandibular posture: an experimental study

Afferent discharges from temporomandibular articular mechanoreceptors make a continuous reflex contribution to the control of the mandibular musculature during static posture and movement. Changes in these discharges occasioned by induced dysfunction of regionally discrete groups of these receptors reflexly alter the activity of the mandibular musculature, so that alterations occur both in the static spatial relationship of the mandible to the maxilla and in the path of mandibular closure.     

The effect of gap arthroplasty on temporomandibular joint ankylosis: an experimental study.

The aim of this study was to demonstrate the functional and anatomical changes after gap arthroplasty release of unilateral temporomandibular joint (TMJ) ankylosis. Five adult sheep weighing an average of 57 kg were used. All right joints were operated. Ankylosis was induced in the right TMJ by articular damage, disk removal and placement of a bone graft plus immobilization wire. At 3 months the gap arthroplasty were performed. All TMJs were examined functionally, radiologically, macroscopically and histologically. Functionally, the range of jaw movements decreased following induction of ankylosis (P<0.0001), increased immediately on release but was reduced again at 3 months after release (the vertical movement, no statistically significant difference; the right movement, P<0.001; the left movement, P<0.0001). Histologically, all operated joints showed fibrous adhesions across the gap, and further, the articular surface was irregular with osteophytes and with bony islands in the gap. This appearance is more consistent with a fibrous reankylosis than a functioning pseudo joint. This study shows that the gap arthroplasty for TMJ ankylosis did not restore the TMJ functionally and histologically to the preexisting state.     

Panoramic imaging of the temporomandibular joint: an experimental study using cadaveric skulls.

OBJECTIVE: The purpose of this study was to determine if condylar morphology can be accurately depicted on the panoramic radiograph and if variations in condylar anatomy affect the radiographic appearance of the condyle. STUDY DESIGN: The shape and angulation of the condyle were determined on 8 cadaveric human skulls. Lead foil markers were then placed on the articulating surface and lateral and medial pole of each condyle. A panoramic radiograph was made of each skull and the position of the markers was assessed. RESULTS: The true shape of the condyles was not recognizable on any of the panoramic images. The exact location of the articulating surface and medial and lateral poles could not be predicted on the panoramic images without markers. The location of these structures varied depending on the amount of condylar angulation. CONCLUSION: Because of the radiographic variations produced by differences in condylar angulation, it is not possible to accurately determine condylar morphology on the panoramic radiograph. Therefore, its value in providing the detailed information needed to guide diagnosis and treatment of the temporomandibular joint patient is limited.