[Condylectomy by intraoral approach for osteochondroma of the mandibular condyle].
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Chondroma↗
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Results for “MANDIBULAR CONDYLE”
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New aspects of the histology of the mandibular condyle in the rat.
The function of the multipotential mesenchymal cells in the mandibular condyle was studied histochemically and histologically in 27 Long Evans/Turku rats. Sagittal sections from the temporomandibular joint were stained with haematoxylin and eosin, toluidine blue, or van Gieson's stain. A weakly orthochromatically stained fibrous layer was followed in the upper region by a weakly metachromatically stained mesenchymal cell layer. Deep within this was a strongly metachromatically stained layer of immature chondroblasts. The metachromasia of the matrix of these layers disappeared abruptly in an anterior direction and gradually in a posterior direction. The changes in the staining reactions are explained by the fact that mesenchymal cells can differentiate into chondrogenic or osteogenic cells depending on the environmental conditions. A new hypothesis is presented according to which regulation of the direction of condylar growth is achieved by choosing the cells for chondrogenesis more posteriorly or anteriorly from among the mesenchymal cells covering the whole condylar cartilage.
Adaptation, Physiological↗
[Osteochondroma of the head of the mandibular condyle in a 68-year-old woman (author's transl)].
The interest of this case lies in the fact that an osteochondroma of the head of the mandibular condyle is rarely seen, its appearance in a women aged 68 years (it is usually noted in young subjects), and the good results after surgery (controlled by radiological examination two years later).
Aged↗
Dislocation of the mandibular condyle into the middle cranial fossa: report of a case with 5 year CT follow-up.
A 17-year-old patient suffered a dislocation of the right mandibular condyle into the middle cranial fossa following a motorcycle accident. Reduction was delayed because of serious orthopaedic injuries. The condyle was relocated into the glenoid fossa through a combined neurosurgical and preauricular approach. Five years later the patient presented for removal of wisdom teeth and a CT-scan was done to determine the effects of the trauma and management to the condyle. A fibro-osseous ankylosis had occurred in the right temporomandibular joint. The radiological changes confirm that early management appears to improve the prognosis for these injuries.
Adolescent↗
Testosterone stimulates insulin-like growth factor-I and insulin-like growth factor-I-receptor gene expression in the mandibular condyle--a model of endochondral ossification.
Puberty is associated with an increase in the plasma concentration of sex steroids, GH, and insulin-like growth factor-I (IGF-I). Gonadal steroid hormones are important for the normal pubertal growth spurt and skeletal growth. The mechanism by which gonadal steroids induce skeletal growth is still not fully understood. To better understand the direct effect sex steroids have on bone growth, we studied an isolated organ culture system of the mandibular condyle, derived from 3.5-5.5-week-old male and female mice. We found that testosterone 10(-6) M, but not estradiol, stimulated thymidine incorporation into the DNA of male-derived condyle. Three days of testosterone treatment doubled the condyle size and increased the chondroprogenitor zone, while maintaining the normal gradient of the developing chondrocytes. Immunohistochemistry and in situ hybridization techniques showed that testosterone stimulated IGF-I and IGF-I-R and their messenger RNAs (mRNAs) mainly in the mature chondrocyte layer. Immunoneutralization of IGF-I in the testosterone-treated condyle caused the disappearance of the chondroblast and young chondrocyte layers, though the progenitor cell layer remained almost unaffected. Overtreatment with testosterone (dose or duration) accelerated condylar ossification. In the presence of testosterone 10(-5) M (high dose), calcification "climbs" up to the chondroprogenitor zone, and most of the condylar chondrocytes are replaced by bone tissue. Similar changes occurred after 7 days of testosterone treatment (long duration) with 10(-6) M. In conclusion, testosterone stimulates growth and local production of IGF-I and IGF-I-R in chondrocyte cell layers of an isolated organ culture of mice mandibular condyle. Part of the effect testosterone has on condylar growth is mediated by IGF-I.
Animals↗
Differential effects of hypothyroidism on the cartilage and the osteogenic process in the mandibular condyle: recovery by growth hormone and thyroxine.
Hypothyroidism was induced in young female Sprague-Dawley rats by the addition of methimazole (50 mg/kg BW.day) to drinking water for a period of 7 weeks (7-14 weeks of age). Replacement therapies of 0.7 U/kg BW human GH (hGH), 15 micrograms/kg BW L-T4 (T4), and a combination of hGH and T4 at the same doses were introduced during the last 2 weeks of the experiment. The responses of the cartilage and subchondral spongiosa of mandibular condyles were assessed by morphological and morphometric parameters. In addition, immunohistochemical localization of the GH receptor and insulin-like growth factor-I was determined by the streptavidin-biotin-peroxidase technique. In the hypothyroid rats, the trabecular bone volume of the subchondral spongiosa increased by 49%, indicating osteopetrosis. Along the ossification front, bone trabeculae occupied 18% and vascular elements 82% in mandibular condyles of control rats, whereas in hypothyroid rats, the percentage occupied by bone trabeculae increased to 89%. The cellularity of the cartilage in hypothyroid condyles was markedly reduced and was fully restored by T4, but not by GH replacement. Immunohistochemistry revealed the presence of GH receptors throughout the condyle regardless of the thyroid state of the animal. On the other hand, insulin-like growth factor-I immunohistochemical localization revealed the peptide to be present at all maturational stages of the cells in condyles from control and T4-treated rats, but to be lacking in young chondrocytes of hypothyroid and hGH-treated rats. This result demonstrates that the hypothyroid cartilage is compromised in its response to hGH.
Animals↗
Pseudocysts of the mandibular condyle in children.
The authors evaluated the panoramic radiographs of 1,193 consecutively treated patients 18 years old and younger for the presence of asymptomatic radiolucencies in the mandibular condyles. The 27 radiographs initially selected were examined by four independent reviewers. Of the 1,193 patients, 18 (1.5 percent [10 female and eight male]) met the criteria for condylar pseudocysts. Follow-up radiographs showed minimal or no change in size of the radiolucencies. Clinicians need to be aware of these anatomic variations so that patients are not subjected to inappropriate treatment.
Adolescent↗
Posterior dislocation of mandibular condyle into external auditory canal. A case report.
A case is reported of a 49-year-old edentulous patient who suffered a posterior dislocation of the right fractured mandibular condyle causing a fracture of the tympanic plate. This was associated with a right transverse fracture of the petrous bone and an intact tympanic membrane. Some of the problems related to this condition are discussed.
Ear Canal↗
A histomorphological investigation of the effect of cyclosporin on trabecular bone of the rat mandibular condyle.
The effect of cyclosporin A (CSA) on the condylar trabecular bone was evaluated by microscopy. Twenty, 5-week-old male Sprague-Dawley rats were divided into a treated and a control group. Animals in the treated group received CSA, 15 mg/kg body weight, by gastric feeding daily for 4 weeks; controls received the vehicle only. Five animals from each group were killed at the end of weeks 2 and 4. After histological processing, 10 tissue sections from the mid-part of the mandibular condyle were examined. Generally, a histopathological osteopenia was observed around the condyle after CSA treatment, especially at the end of week 4. In the control animals, the trabecular bone volume steadily increased from weeks 2 to 4 (from 0.46+/-0.07 to 0.61+/-0.07 mm(3)/mm(3)). However, the bone volume was significantly less in the CSA group than in the control group at both times (0.33+/-0.02 vs 0.46+/-0.07 and 0.26+/-0.07 vs 0.61+/-0.07 mm(3)/mm(3) for CSA vs control group at the end of weeks 2 and 4, respectively). Conversely, an increased marrow volume was observed in the CSA group at both these times (0.60+/-0.02 vs 0.42+/-0.08 and 0.71+/-0.06 vs 0.31+/-0.06 mm(3)/mm(3) for CSA vs control group at the end of weeks 2 and 4, respectively). Decreases were also observed in trabecular thickness, osteoid seam width, osteoid volume and cortical bone width. Because trabecular bone mass, osteoid mass and cortical bone thickness all showed a decrease after CSA at both times, an inhibitory effect of CSA on trabecular bone formation in the mandibular condyle is proposed.
Animals↗
A comparative study of unilateral dislocated mandibular condyle fractures in the rabbit.
PURPOSE: The purpose of this study was to clarify the influence of patients age and the degree of dislocation on the healing of mandibular condyle fractures. MATERIAL AND METHODS: Sixty-two Japanese white rabbits (30 adolescent and 30 adult ones) were used. They underwent unilateral condylar neck osteotomy. The proximal fragments were positioned differently. In group I animals, the fragments were reduced into the original position, in group II animals the small fragment was dislocated 55-90 degrees to the ramus. In group III animals the proximal fragment was dislocated 135 degrees to the ramus. Gross and microscopic assessment was performed 4, 6, 8, 12 and 24 weeks postoperatively. RESULTS: In adolescent animals, complete healing of the fracture was observed, irrespective of the degree of dislocation. In the adult animals, there was complete healing of the fractures in groups I and II. In group III animals, there was a decrease of ramus height accompanied by some fibro-cartilaginous changes. CONCLUSION: Even in rabbits condylar deformation has been found following heavily dislocated artificial condylar fractures in adult animals. This result will help to decide for or against surgical treatment of condylar fractures in humans.
Age Factors↗
Radiological variations in mandibular condyles of Finnish students, one group orthodontically treated and the other not.
Panoramatomograms of 968 students (355 males and 613 females) aged between 19 and 25 years were evaluated with special emphasis on the mandibular condyles. Two-hundred-and-thirty-five students (24.3 per cent) had been treated orthodontically. Radiographic variations in the condyles were significantly more common in the orthodontically treated group as a whole and in males (n = 71, P < 0.001), but not in females (n = 164). No age correlation in the frequency of condylar variations was found in either group. In terms of individual severe variation, flattening of the articular surface (P < 0.001) and subcortical sclerosis (P < 0.01) were more common in the orthodontically treated students. In the untreated subjects (284 males and 449 females), females had more variations (9.3 per cent) in their condyles than males (3.7 per cent P < 0.001). In the orthodontically treated students the percentages with condylar variations were 21.1 per cent in males and 16.5 per cent in females (N.S.).
Adult↗
Total osteolysis of the mandibular condyle in progressive systemic sclerosis.
This report calls attention to the complete resorption of the mandibular condyle in progressive systemic sclerosis (scleroderma), a previously unreported finding. This was associated with osteolysis of the ipsilateral coronoid process, both mandibular angles, and autoamputation of the fingertips. The Panorex provides a simple, effective method for studying the mandible in systemic sclerosis. Similar mandibular osteolysis with vinyl chloride exposure is noted.
Bone Diseases↗
Bone tissue stiffness in the mandibular condyle is dependent on the direction and density of the cancellous structure.
Variation in the apparent stiffness of cancellous bone is generally ascribed to variation in cancellous structure and density, while the bone tissue stiffness is assumed to be constant. The purpose of the present study was to examine whether the bone tissue stiffness is dependent on the direction and density of the cancellous structure. Bone tissue stiffness was estimated by combining mechanical testing and micro-finite element (micro-FE) modeling on cylindrical bone specimens obtained from the human mandibular condyle. One set of specimens was tested in the vertical direction of the condyle (n = 39) and another set in the transverse direction (n = 30). The cancellous structure of the specimens was characterized by micro-CT. The apparent bone stiffnesses predicted by the FE model correlated strongly (r2 = 0.91) with the measured apparent bone stiffnesses. Apparent bone stiffness in the transverse direction was considerably smaller than that in the vertical direction. In contrast, the predicted bone tissue stiffness was significantly larger in the transverse direction (E = 13.70 GPa) than in the vertical direction (E = 11.87 GPa). In addition, bone tissue stiffness correlated negatively with the bone volume fraction and directional sensitivity of the bone tissue stiffness increased with a decrease of bone volume fraction. The results suggest that the transversely oriented trabeculae in the mandibular condyle are stiffer and more mineralized than the vertically oriented trabeculae and that bone loss is compensated by an increase in the degree of mineralization.
Aged↗
[Hypertrophy of the mandibular condyle: diagnostic approach (contribution of nuclear medicine)].
In this study the authors present a clinical and radiological approach of condylar-hyperplasia. They insist on the importance of investigating the growing potentialities of the mandibular condyles by using SPECT-type skeletal scintigraphy before establishing the treatment-planning.
Humans↗
Mandibular condyle traits in Neanderthals and other Homo: a comparative, correlative, and ontogenetic study.
The relationship between the mandibular condyle and the crest of the mandibular notch (CMN) has historically entered into discussions of Neanderthal characteristics and was recently suggested to be autapomorphic in Neanderthals. The Neanderthal CMN has been described as intersecting the condyle in the middle, while the modern human CMN runs to the condyle's lateral end. A large lateral condylar tubercle (LCT) has also been observed in Neanderthals and thought to be related to medial (or less lateral) CMN position. In addition, the presence of a less lateral CMN early in ontogeny, as seen in the Amud 7 infant, has been argued to demonstrate great evolutionary divergence in Neanderthals. Using a scoring system for each trait, this study first examines the expression of CMN position and LCT size in 102 adult modern humans and in samples of Neanderthals and other fossil Homo. Then, CMN position is scored in 208 subadult modern humans to elucidate the ontogeny of this trait. Results show that CMN position is not autapomorphic in Neanderthals, but Neanderthals have significantly more CMNs in the least-lateral score category than does the modern human sample. Large LCTs are found to be strongly predictive of less lateral CMN position, although less lateral CMN position may exist in the absence of a large LCT. The complex ontogenetic pattern of CMN expression observed indicates that features of subadult and adult condylar morphology cannot be constructively compared without first considering subadult morphology on its own functional and developmental terms.
Adolescent↗
The ultrastructural distribution of proteoglycans in normal and rachitic growth cartilage from the mandibular condyle of the rat.
The mandibular condylar cartilages from normal and rachitic weanling rats were stained with ruthenium red to demonstrate the distribution of proteoglycan. In the rachitic animal there was an increased concentration of ruthenium-red positive granules in the pericellular region of chondrocytes from the extended hypertrophic zone when compared with the controls. These aggregates may represent unmodified proteoglycan which excludes calcium and thereby prevents matrix calcification.
Animals↗
Fine structure of cartilage elastic system fibers, in particular those of the mandibular condyle.
Light microscopy of the mandibular joint tissues from fetal mice show a distribution of fibrillar structures in the articular fibrous capsule covering the condylar head. Further SEM and TEM studies were conducted on autoclaved xiphoid and mandibular condylar processes of the fetuses for observation of the elastic system fibers in these cartilaginous tissues. SEM showed that non-collaginous fibers branched and united to form a complicated network in the cartilage. A fine structure study on diameter distribution of the fibers indicated elastogenesis in the differentiating cell layer and fiber maturation in the articular surfaces and calcification layer, thus suggesting a sequential development, growth, and degeneration of the cellular and fibrillar components in the cartilage, as well as bidirectional cell differentiation in the growing mandibular joint. A further TEM study on these autoclaved connective tissues showed the elastic system fibers in the network to be composed of fine microfibrils and amorphous elastin. The elastic fibers in the condylar cartilage were a loose network having many tortuous main and oblique elastic fibers, and coiling oxytalan fibers.
Animals↗
RECONSTRUCTION OF BOTH MANDIBULAR CONDYLES WITH METATARSAL BONE GRAFTS.
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Bone Transplantation↗