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Results for “MANDIBULAR CONDYLE”

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PubMed1994

Effect of mechanical forces on chondrocyte maturation and differentiation in the mandibular condyle of the rat.

The effects of mechanical factors on the growth of the mandibular condyle were studied by monitoring the maturation of the mesenchymal cells in 55 rats. Thirty-five animals were fed normal pellet food, and 20 were fed a soft diet and their incisors were cut regularly. 3H-thymidine was injected intraperitoneally three days before death at 18, 23, or 33 days. Histologic sections showed the most advanced 3H-thymidine-labeled cells to occur deep in the cartilage, in the lower hypertrophic cell layer in anterior and posterior regions of the condyle, and in the upper hypertrophic cell layer in the superior region at the age of 18 days. A distinct difference in the maturation state of the labeled cells could also be observed between these regions. In animals fed a soft diet, maturation was slower in the superior region of the condyle and faster in the posterior region than in the normal rats. The rate at which cells stepped out of the proliferating cell pool was measured by use of monoclonal antibodies against proliferating cell nuclear antigen. The ratio between labeled cells in the proliferating cell layer and the number of labeled cells beneath it was greater in control animals than in the soft-diet animals. The rate of differentiation and maturation of mesenchymal cells into chondrocytes seems to be controlled by mechanical factors.

Animals↗
PubMed1987

Osteoma in mandibular condyle.

A case of peripheral osteoma occurring in the mandibular ramus in a 26-year-old man is reported. Radiographic examination revealed a pedunculated, protruding globular, bone-like opaque mass around the notch of the right mandibular ramus. Histopathological examination showed a lamellar bone structure with irregular arrangement. Wide trabeculae, narrow interstitial areas, and many fibrovascular channels were detected by scanning electron microscopy. Thus, characteristic findings of a compact osteoma were obtained clinically and histopathologically.

Adult↗
PubMed1988

Three-dimensional ultrastructure of the Golgi region of the formative chondrocyte in newborn rat mandibular condyle.

The three dimensional ultrastructure of Golgi region of formative chondrocytes from newborn rat mandibular condyle was examined by means of the method based on dilute osmium maceration with a high-resolution scanning electron microscope. The large area of formative chondrocytes was occupied by the cytoplasmic organelles related to matrix-synthesis such as Golgi apparatus, rough endoplasmic reticulum (RER) and mitochondria. The Golgi region of formative chondrocytes was composed of the limiting membranous structures such as some groups of the stacks of Golgi cisterns, vesicles, vacuoles, secretory granules, reticular constituents and small tabular or tubular RER. The Golgi cisterns were composed of both small tabular parts and rod-like parts arising from tabular parts. Small tabular parts were furthermore subdivided into three types of many, few and no penetrated ones. Reticular constituents were made up of limiting membrane visible as smooth image by scanning electron microscopy, therefore, are assumed to be one part of the GERL (Golgi apparatus-endoplasmic reticulum-lysosome).

Animals↗
PubMed1987

Structure and growth activities of the mandibular condyle in monkeys (Macaca fascicularis): II. Synergistic behavior of cell dynamics and metabolism.

The mandibular condyles of eight growing male monkeys (Macaca fascicularis) were analyzed by using a combination of radioautographic and morphometric techniques. This was done with the aim of examining the dynamics in the structure and growth activities of the articular tissue covering as well as of the subchondral zone of erosion. The animals received 1 mCi/kg body weight 3H-proline 24 hr and 0.5 mCi/kg body weight 3H-thymidine 3 hr prior to death. Their age was estimated on the basis of skeletal maturation as recorded from radiographs of the hand and wrist. Consistently, the proliferative activity in the intermediate layer, the rates of cell turnover and growth of chondroblasts and chondrocytes, the rates of extracellular matrix production in the intermediate and chondral layers, as well as the resorptive and appositional activities in the zone of erosion were characterized by an in-concert behavior. This behavior suggests a general synergistic control of the various cell dynamic and metabolic processes affecting the rate of normal condylar growth.

Aging↗
PubMed2006

Osteochondroma in the mandibular condyle that caused facial asymmetry: a case report.

Osteochondroma is the most common benign tumor of the axial skeleton, though it is rarely found in the oral and maxillofacial regions. Reported is a case of osteochondroma affecting the mandibular condyle of a 22-year-old Japanese woman. The patient visited the hospital with the chief complaint of facial asymmetry. She had pain with clicking on her right temporomandibular joint (TMJ), resulting in trismus and facial asymmetry with a chin deviation to the left side. Her maximum jaw opening was 34 mm, with moderate left TMJ tenderness. There was Class I occlusion without open bite. Panoramic radiography and computed tomography (CT) revealed an enlarged right mandibular condylar head. Magnetic resonance imaging (MRI) also showed an enlarged condyle with hyperintense bone marrow on a T2-weighted image. Condylectomy and condyloplasty were performed. Surgical specimen of the lesion revealed osteochondroma of the mandibular condyle head. Two months after the initial surgery, facial asymmetry was surgically corrected by Le Fort I osteotomy and chin reduction. The patient was discharged from the hospital with no subjective complaints. At the time of this report, the patient had been followed up for seven months, and there had been no evidence of recurrence.

Adult↗
PubMed1987

Further characterization of the chondroprogenitor zone in mandibular condyles of suckling mice. An ultrastructural and cytochemical study.

In the neonatal mouse the mandibular condyle serves as an important growth center for the developing mandible. The youngest cells in this organ are the chondroprogenitor cells that are the source for new differentiating chondroblasts. The present study provides new data concerning the fine structure and cytochemical characteristics of the cartilage precursor cells as seen in suckling mice. The condylar chondroprogenitor cells normally reveal a mesenchyme-like appearance with multiple, elongated cell processes that enable close contact between neighboring cells. These cells also exhibit a variety of pinocytotic vesicles, coated pits and appear to be actively involved in the internalization of a fluid-phase marker horseradish peroxidase. Further, the progenitor cells were found to contain trimetaphosphatase reaction products within lysosomal bodies and alkaline phosphatase reactivity along their plasma membrane. Precipitates of calcium complexes in the form of calcium pyroantimonate could be demonstrated in association with the plasmalemma of the cells as well as with the extracellular collagen fibrils. Matrix granules, representing cartilage proteoglycans, became a distinct feature following staining with ruthenium red and were found to be in close contact with the extracellular collagen fibrils and with the plasmalemma. Hence, in addition to their active role in cell proliferation, the progenitor cells are also involved in the synthesis and secretion of major extracellular macromolecules such as collagen and proteoglycans.

Acid Anhydride Hydrolases↗
PubMed2000

[Immunohistochemical study of type I and type II collagen in the remodelling of the supraosseous tissue of mandibular condyle].

OBJECTIVE: Previous studies focused on the pathological changes of the supraosseous tissue of mandibular condyle (STMC), but little is known about extracellular matrix during the remodelling activity of temporomandibular joint (TMJ). This study will examine the characteristics of type I and type II collagen during this process. METHODS: The animal model was established by extracting the left lower molars of adult rabbits. Temporomandibular joints of two sides were taken after 2 weeks, 1 month and 3 months respectively, and embedded in paraffin. Then 5 microns-thick sections were cut and processed for immunohistochemistry and haematoxylin-eosin staining. An immunohistochemical ABC method was used to determine the local changes of type I and type II collagen. The positive cells were counted in order to analyze quantitative changes. RESULTS: After loss of teeth from 2 weeks to 3 months, the number and arrangement of chondrocytes changed. Some chondrocyte clusters were also observed in the non-extraction side of TMJ. Most STMC cells stained positively with anti-type I collagen, but weakly in chondrocytes and hypertrophic chondrocytes. On the other hand, type II collagen only existed in chondrocytes and some hypertrophic chondrocytes. The expression of type I collagen decreased after 2 weeks and became stronger after 1 and 3 months, furthermore distributed unevenly in STMC. Some hypertrophic chondrocytes in the non-extraction side showed strong positive staining with anti-type I collagen. Type II collagen in two sides decreased after 2 weeks, then became stronger after 1 and 3 month, but the whole level was less than that of the control group. Expressions of two kinds of collagen were compared between two sides. Type I collagen in the non-extraction side was stronger than that in the extraction side, while type II collagen had an opposite result. CONCLUSION: Adult rabbits have a limited remodelling ability, and the synthesis and secretion of type I and type II collagen will change when the remodelling is beyond a proper extent, which will lead to impaired resistance and elasticity of fibrocartilage.

Animals↗
PubMed1989

Lateral displacement of the intact mandibular condyle. Review of literature and report of case with associated facial nerve palsy.

A rare injury is described, in which symphyseal fracture of the mandible was associated with lateral displacement of the intact mandibular condyle into the temporal fossa and damage to the ipsilateral facial nerve with unilateral facial paralysis. Management of the injury was associated with an episode of acute laryngeal obstruction, necessitating emergency tracheostomy.

Adult↗
PubMedDate not supplied

Chip fractures of the mandibular condyle.

Four patients suffered from trauma of the temporomandibular (TM) joints. They were examined by routine x-ray procedures. The x-ray films failed to demonstrate a chip fracture of the head of the mandibular condyle. A coronal computed tomographic (CT) view established the fracture shortly after the trauma in three patients. These patients improved clinically after physiotherapy. The fourth patient was retrospectively diagnosed as having a chip fracture of the mandibular head. She underwent CT scan 10 months posttrauma , and ankylosis of the TM joint was established. The mechanism and the clinical symptoms of this injury, which have not been previously described, are reported in this article.

Adolescent↗
PubMed2004

Comparative study of intra-articular irrigation and corticosteroid injection versus closed reduction with intermaxillary fixation for the management of mandibular condyle fractures.

OBJECTIVE: To evaluate the clinical outcome of a modified conservative treatment protocol involving intra-articular irrigation and corticosteroid injection into the superior joint compartment (SJC) of patients with fresh mandibular condyle fractures. Study design A total of 26 consecutive unilateral fresh condylar fractures in 26 patients were divided into the intra-articular irrigation (IR) group (14 patients, 14 joints) and the conventional conservative treatment (CC) group (12 patients, 12 joints). In the IR group, the SJCs of the fractured joints were irrigated with saline solution and injected dexamethazone sodium, followed by conventional rehabilitation. In the CC group, patients were treated by closed reduction with intermaxillary fixation (IMF) for 2 weeks, followed by conventional rehabilitation. Clinical outcome at 1 month, 3 months, 6 months, and 1 year after injury was determined by clinical examination of jaw motion, joint pain, and occlusal changes. The posttreatment results were compared with the pretreatment baseline data. Between-group differences in clinical parameters were analyzed. RESULTS: There were significant between-group differences in the range of mandibular motion at 1 month and 3 months after injury (1 month, P=.0022; 3 months, P=.0022). In the IR group, joint pain was well relieved from the early stage of treatment. Occlusal changes were found in 1 patient in the IR group and 4 patients in the CC group at 1 year after injury. CONCLUSIONS: The modified treatment protocol involving intra-articular irrigation and corticosteroid injection into the SJC is a more effective and quick-acting modality than conventional closed reduction with IMF for functional recovery and control of clinical symptoms of patients with unilateral fresh condylar fractures.

Adult↗
PubMed1994

The position of the mandibular condyle at maximal mouth opening in normal subjects.

PURPOSE: To investigate the position of the mandibular condyle at maximal mouth opening in individuals 19 to 30 years of age with no functional disorders of the masticatory system. PATIENTS AND METHODS: Measurements were made in 153 subjects (99 men, 54 women), and 41 men and 44 women had transcranial radiographs taken of their right and left temporomandibular joints in the closed and maximal opening positions. RESULTS: In all subjects the condyle moved forward beyond the summit of the articular eminence, and in more than half the subjects the condyle was located inferior to the eminence at maximal opening. CONCLUSION: The correlation between maximal opening and anterior shift of the condyle from the summit of the eminence was significant, but the correlation with vertical shift of the condyle was not significant. The correlation between the form of the glenoid fossa (length and depth) and anterior or vertical shift of the condyle from the summit of the eminence also was not significant.

Adult↗
PubMed1998

Differential responses of mandibular condyle and femur to oestrogen deficiency in young rats.

This response of condyle and femur was evaluated by histomorphometry. Five female Sprague-Dawley rats, 6 weeks of age, were subjected to bilateral ovariectomy, and five others were sham-operated. They were then killed 32 days later. Ovariectomy significantly increased the total thickness of the condylar cartilage and distal femoral growth-plate cartilage in the young, growing rats. Ovariectomy caused a 2-fold increase in thickness of the proliferative layer and a 4-fold increase in thickness of the hypertrophic layer in the condylar cartilage, and a 1.3-fold increase in thickness of the proliferative layer in the epiphyseal growth cartilage of the femur. Ovariectomy had no effect on the percentage of trabecular bone volume, the percentage of the bone surface covered by osteoblasts (Ob.S/BS) and osteoclasts (Oc.S/BS), and number of osteoclasts per bone surface (N.Oc/BS) in the mandibular condyle. On the contrary, ovariectomy caused a 68.5% decrease in bone volume, a 4-fold increase in Ob.S/BS, and 2-fold increases in Oc.S/BS and N.Oc/BS in the secondary spongiosa of the rat distal femur. Thus there was a prominent difference in the response to oestrogen deficiency between the mandibular condyle and femur in young growing rats.

Animals↗
PubMed2003

[Our physiotherapy treatment of articular fractures of the mandibular condyle].

Physical therapy greatly contributes to improved function of the injured temporomandibular joint, particularly after trauma. In our unit, we use the Delaire rehabilitation method for patients presenting a fracture of the mandibular condyles. This method involves active mobilization, first with assistance, then with facilitation, and finally against resistance. A rehabilitation session starts with a preparation of the teguments and muscles associated with relaxation exercises. The joint is first mobilized by assisted movements if needed. When unassisted motion becomes possible, propulsion, diduction and open-close exercises are then performed with neuromuscular facilitation. When sufficient amplitudes have been achieved, the program proceeds with opposed exercises. By inducing propulsion and diduction (lateral pterygoid muscle) movements, physical therapy stimulates regeneration of the condylar unit, thus facilitating optimal functional rehabilitation. Posture and passive motion methods, which in our opinion are poorly adapted to the temporomandibular joint, are used little in our unit. Since condylar regeneration is controlled by functional factors, the lateral pterygoid muscle is an important element. Good functional outcome, and the absence of ankylosis, depends directly on the quality of active rehabilitation.

Humans↗
PubMed1983

Size and shape of the mandibular condyle in primates.

The relationships between the size of the articular surface of the mandibular condyle and masticatory muscle size, tooth size, diet, and biomechanical variables associated with mastication were studied by taking 12 measurements on skulls of 253 adult female anthropoid primates, including three to ten specimens from each of 32 species. In regressions of condylar length, width, or area against body weight, logarithmic transformations substantially improve the fit of the equations compared with untransformed data. There is a strong relationship between condylar measurements and body weight, with all correlations being .94 or higher. The slopes of the allometric regressions of length, width, and area of the condylar head indicate slight positive allometry with body size. Folivorous primates have smaller condyles than frugivorous primates, and colobines have smaller condyles than cebids, cercopithecines, or hominoids. When colobines are eliminated, the differences between frugivores and folivores are not significant. However, the two species with the relatively largest condyles are Pongo pygmaeus and Cercocebus torquatus, suggesting that there may be a relationship between unusually large condylar dimensions and the ability to crack hard nuts between the teeth. Cranial features having strong positive correlations with condylar dimensions include facial prognathism, maxillary incisor size, maxillary postcanine area, mandibular ramus breadth, and temporal fossa area. These data are interpreted as indicating that relatively large condyles are associated with relatively large masticatory muscles, relatively inefficient mandibular biomechanics, and a large dentition. These relationships support the growing evidence that the temporomandibular joint is a stress-bearing joint in normal function.

Animals↗
PubMed1976

[Traumatic intracranial penetration of the mandibular condyle].

The authors report a case of severe multiple trauma in which, as a result of the large number of complex injuries together with necessary therapeutic measures, the intra-cranial penetration of the mandibular condyle was unnoticed during the first months following the accident. They emphasize the discordance between the anatomical lesions and their clinical manifestations. Thus a complete radiological examination is necessary at a secondary stage in order to detect such lesions which, by contrast to that which might be supposed, are not obvious clinically. As far as treatment is concerned, rather than resorting to orthopaedic menoeuvres with imprecise traction and which, in any case, fail to resolve the entire problem. the authors recommend a combined maxillo-facial neurosurgical operation.

Adult↗
PubMed1980

[Functional structure of the growing human mandibular condyle (author's transl)].

This histological study describes the functional structure of the growing human mandibular condyle at birth. It consists of a dense conjunctive membrane of meniscal origin covering over the pre-osteoblastic condylar zone. The two muscle bundles of the external pterygoid muscle, the meniscal and condylar bundles, ensure, because of their contractile forces acting in opposite directions, the dissociation of the conjunctive and pre-osteoblastic zones, followed by a mitotic response of the latter. This mechanism is of prime importance during the period of somatotropic hormone secretion, that is to say, during the growth period. This structure and mechanism of growth validate the hypothesis of the predominance of postural and functional phenomena during mandibular condylar growth. The behaviour of human temporomandibular joints during growth would therefore be analgous to that of a membranous suture.

Cartilage, Articular↗
PubMed2004

Bifid mandibular condyle: archaeological case report of a rare anomaly.

In this paper, an archaeological case of unilateral bifid mandibular condyle is presented. This uncommon anomaly is characterized by a division of the mandibular condylar head. In this case, the left condyle was divided into two articulating surfaces oriented mediolaterally; two articular facets on the anterior wall of the glenoid fossa for the double condyle were observed. The morphological and radiological analysis do not show any evidence of injuries or degenerative pathology. Taking into account the two main causes of bifid condyle suggested in the literature (traumatic and developmental), an embryopathy by teratogenic agents is proposed as a possible aetiology of the bifid condyle reported here.

History, Ancient↗