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Ultrastructure of the articular surface of the condyle in temporomandibular arthropathy.

The ultrastructure of the surface of normal human mandibular condyles is described and compared with specimens from condyles in cases of degenerative joint disease (arthropathy). Normal surfaces exhibited a nearly structurless layer about 2 microns thick, which seemed to correspond with the lamina splendens of other joints. The underlying structure of dense interlacing bundles of collagen is described. Surfaces of all pathologic condyles showed loss of lamina splendens, alteration of collagen size, and evidence of dissociation of both the collagen and its surrounding ground substance. Deeper levels showed aggregations of bizarre structures, which the authors term "vermiform bodies," and which appear to be collections of abnormal amounts and types of elastic tissue. Its distribution suggests a stress elastosis, which may contribute to the loss of mechanical integrity of articular surfaces in arthropathy. The surface changes may be reflected at the clinical level as impairment of the normal low-friction qualities of joint components associated with limitation of movement and joint sounds.

Adult↗

Endoscopy-assisted open treatment of condylar fractures of the mandible: extraoral vs intraoral approach.

By using an endoscopy assisted extraoral and transoral approach for open reduction of condylar mandible fractures with limited incisions, the risk of facial nerve damage and extensive visible scars can be reduced. The endoscopy-assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 13 presented with additional mandibular fractures. Nine of the 17 patients were treated by a submandibular approach and eight by a transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approach using an endoscopy-assisted technique. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle, even when dislocation with lateral override was present. In four patients, angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trochars were not needed in these four patients. The extraoral approach was indicated for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗

Changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Distraction osteogenesis (DO) is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint have not been well documented. The purpose of this study was to evaluate the effect of DO, at varying rates, on the mandibular condyle and articular disc. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0 day latency and rates of 1, 2, or 4 mm/d for a 12-mm gap. After the animals were killed (0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested and evaluated to determine changes in 1) condylar form and size, 2) condylar surface, and 3) the articular disc. RESULTS: Articular surfaces of the condyles in control animals were smooth, with no irregularities or erosions. In animals undergoing distraction, ipsilateral condyles showed increasing changes in morphology and AP dimension, and surface contour irregularities as the DO rate increased. These changes were present, but to a lesser degree, in the contralateral condyles. Articular discs of both ipsilateral and contralateral sides showed variable thinning at the medial aspect at end DO. After 90 days, changes in the condyles and discs were reduced by remodeling except in the 4 mm/d DO groups. CONCLUSIONS: Results of this preliminary study indicate that gross changes occur in condyles and discs after unilateral mandibular DO. These changes are more severe at faster distraction rates (4 mm/d) and tend to resolve during neutral fixation when a rate of 1 mm/d is used.

Adaptation, Physiological↗

Histopathologic comparison of normal and hyperplastic condyles.

OBJECTIVE: The aim of this study was to compare normal and hyperplastic mandibular condyles using two different histopathologic staining techniques. STUDY DESIGN: Nine cases of condylar hyperplasia and 13 normal cases were studied after hematoxylin and eosin and silver staining. RESULTS: There was a significant difference between the two groups in the thickness of the hyperplastic cartilage layer of condylar soft tissue (P = 0.017). Also, the number of argyrophilic nucleolar organizer regions was significantly higher in the condylar hyperplasia case group (P = 0.0001). No significant differences could be demonstrated in cartilage island frequency, penetration depth, and distribution in the cancellous bone of condyles. CONCLUSION: The thickness of the hyperplastic cartilage layer appears significantly increased in condylar hyperplasia. In addition, argyrophilic nucleolar organizer region count may be useful in histopathological identification of condylar hyperplasia.

Adolescent↗

Mirror image condylar hyperplasia in two siblings.

A Hispanic family with an unusual clinical and radiological pattern of condylar hyperplasia is presented. Mirror images of condylar hyperplasia, malocclusion of teeth, and shift of midline of the mandible were seen in two brothers. The father had a similar abnormality of his left mandibular condyle. The condylar hyperplasia in this family indicates that mandibular condylar hyperplasias could be genetic in origin, possibly Y-linked or autosomal dominant.

Adult↗

An image-based approach for designing and manufacturing craniofacial scaffolds.

Bone tissue engineering (BTE), which combines biomaterial scaffolds with biologically active factors, holds tremendous promise for reconstructing craniofacial defects. A significant challenge in craniofacial reconstructive BTE applications is the complex patient-specific geometry that must be reconstructed. In this paper, we present an image-based approach for designing and manufacturing patient-specific craniofacial biomaterial scaffolds directly from CT or MRI data. In this approach, voxel density distribution is used to define scaffold topology. The scaffold design topology is created using image processing techniques. This voxel density distribution is then converted to data that can be used to drive a Solid Free-Form Fabrication machine to either directly build the scaffold or build a mold for the scaffold. Several preliminary applications for craniofacial surgery, including a mandibular condyle scaffold, an orbital floor scaffold, and a general mandibular defect scaffold, are illustrated. Finally, we show applications to in vivo models.

Animals↗

Spontaneous differentiating primary chondrocytic tissue culture: a model for endochondral ossification.

Primary cartilage-derived cell cultures tend to undergo dedifferentiation, acquire fibroblastic features, and lose most of the characteristics of mature chondrocytes. This phenomenon is due mainly to the close matrix-cell interrelationship typical of cartilage tissue, which is vital for the preservation of the cartilaginous features. In this study we present a model for spontaneous redifferentiation of primary chondrocytic culture. Mandibular condyles excised from 3-day-old mice, thoroughly cleaned of all soft tissue, were digested with 0.1% collagenase. These mandibular condyle-derived chondrocytes (MCDC) were cultured under chondrogenesis-supporting conditions; that is, 5 x 10(5) cells/mL were incubated in Dulbecco's modified Eagle medium supplemented with 100 microg/mL ascorbic acid, 1 mmol/L calcium chloride, 10 mmol/L beta-glycerophosphate, 10% fetal calf serum, and antibiotics. Development and growth rates of these cartilage-derived cultures were determined by following morphological and functional changes. MCDC proliferated intensively during the first 24-48 h following plating, showing fibroblast-like (long spindle-shaped) morphology and producing mainly type I collagen. The proliferation rate gradually declined, and the cells developed polygonal shapes and started to produce type II collagen. In the 10-14-day-old cultures, cells began to aggregate in cartilaginous nodules and exhibited positive staining for acidic Alcian blue, type X collagen, and von Kossa. Expression of core-binding factor alpha(1) increased between 3 and 5 days and declined gradually thereafter. The condylar-derived tissue culture presented here depicts a spontaneous redifferentiation chondrocytic tissue culture that exhibits features of mature chondrocytes typically found in skeletal growth centers. The present study offers a model for primary chondrocytic tissue culture, which might serve as a model for in vitro endochondral ossification.

Animals↗

Bifid condyle of the mandible with associated polythelia and manual anomalies.

Syndromes of oro-mandibular-skeletal anomalies are confusing by their ambiguous and overlapping components. It is our purpose to bring attention to a case comprising a group of anomalies: bifid mandibular condyle, asymmetric contralateral ascending ramus of the mandible, supernumerary nipples (polythelia), supernumerary-rudimentary postaxial sixth fingers and clinodactyly. The associated malformations presented do not correspond to any previous report. The case may therefore represent a new malformation syndrome.

Abnormalities, Multiple↗

[Ultrasonic measurement of the elastic properties of goat condyles].

OBJECTIVE: The purpose of this experiment is to investigate the elastic properties of goat mandibular condyles and to provide basic constants for biomechanical study of temporomandibular joint. METHODS: A fresh goat mandible was adopted and the standard condyle specimen of 4 mm x 6 mm x 10 mm was obtained from it. The structure density of the condyle was determined according to Archimede's principle. The transmitting velocities of ultrasonic wave in different directions of goat condyles were measured by using the ultrasonic system, which was composed of a transmitting transducer of 1.25 MHz, a receiving transducer of 2.5 MHz, an ultrasonic analyzer (5052UA) and a digital storage oscilloscope (HP54601A). The elastic coefficients and technical constants could be calculated by elastic equations. RESULTS: The structural density of the sample and the wave velocities in different directions of the condyle were both obtained by direct measurement. And then, nine elastic coefficients and all of the technical constants of orthotropic condyles were calculated. CONCLUSION: 1. It is practicable to measure elastic properties of the condyle by using ultrasonic technique. 2. Goat condyles of the mandible are a type of anisotropic and linearly elastic material. 3. The direction perpendicular to the transverse ridge of the goat condyle has the highest Young's modulus. As to shear modulus, the direction along the transverse ridge shows the highest value.

Animals↗

Growth of a costochondral graft in the rat temporomandibular joint.

The aim of this study was to examine the growth and adaptation of costochondral grafts in the temporomandibular joint (TMJ). An autogenous rib section with either a short, intermediate, or long cartilaginous end was transplanted to replace the right mandibular condyle in 20-day-old rats. At 40 days, the mandibular halves with the short cartilage transplants were shorter than the contralateral halves, whereas the two sides did not differ in length in the rats with the intermediate transplant. The mandibular halves with the longest cartilaginous transplants initially were longer than the contralateral ones. The glenoid fossa was located more laterally as compared with the unoperated side. The results provide evidence that costochondral transplants do not adapt to the functional conditions of the TMJ and that the amount of cartilage in the graft has some bearing on its growth capacity.

Adaptation, Physiological↗

Thin-plate spline analysis of treatment effects of rapid maxillary expansion and face mask therapy in early Class III malocclusions.

An effective morphometric method (thin-plate spline analysis) was applied to evaluate shape changes in the craniofacial configuration of a sample of 23 children with Class III malocclusions in the early mixed dentition treated with rapid maxillary expansion and face mask therapy, and compared with a sample of 17 children with untreated Class III malocclusions. Significant treatment-induced changes involved both the maxilla and the mandible. Major deformations consisted of forward displacement of the maxillary complex from the pterygoid region and of anterior morphogenetic rotation of the mandible, due to a significant upward and forward direction of growth of the mandibular condyle. Significant differences in size changes due to reduced increments in mandibular dimensions were associated with significant shape changes in the treated group.

Case-Control Studies↗

Changes in temporomandibular joint after mandibular subcondylar osteotomy: an experimental study in rats.

The objective of this study was to analyze the changes in the different components of the temporomandibular joint and their relation with age after subcondylar osteotomy. For this purpose 149 Wistar rats were divided into three groups: osteotomy, sham operation, and control. Two experimental ages (30 and 70 days) and radiologic, morphometric, macroscopic, and histologic methods of analysis were used. Different changes were observed in young and adult animals. Subcondylar mandibular osteotomy in growing rats caused anteroinferior displacement of the temporal and mandibular component of the joint. At the end of the experimental period only condylar displacement was maintained. Other changes were flattening of the mandibular condyle, which was transient, and lateral thickening of the articular disc. Subcondylar mandibular osteotomy in adult rats caused slight anterior displacement of the joint components at the end of the experimental period. At this age, although changes similar to those in growing animals were observed in some cases, in other cases the presence of pathologic findings, such as deformation of the condylar cartilage, thickening of the disc, intra-articular adherences, and osteolysis of the temporal fossa, were observed. Changes in the joint components were more marked in growing rats than in adults. In growing rats they affected the form of the condylar process to a greater extent, but the majority of these changes were transient. In adult rats, alterations in the joints were less pronounced, but they affected a greater number of joint components and were permanent.

Adaptation, Physiological↗

[Linear tomography and the Zonarc TMJ program. Reproducibility of condylar position of TMJ after surgical correction of dysgnathia].

In this clinical study the position of the mandibular condyles of 40 patients treated for malocclusion by surgical splitting of the mandibular ramus alone or combined with Le Fort I osteotomies was studied on lateral linear TMJ tomograms. Linear tomograms of the right and left TMJ with the mandible closed were taken from each patient prior to surgery and 6 months postoperatively. The postoperative changes in condylar position wee assessed in terms of direction and amount. Condylar displacements were found in 89% of the examined joints, most of them were less than 2mm. All types and combinations of displacement occurred, however, general trends in direction depending on the type of treatment could not be established with statistical significance. The type of surgical correction, its direction and amount did not seem to have an effect on the direction and amount of condylar displacement resulting. A comparison of the measured values with data in the literature showed that the amount of condylar displacement was markedly less--this seemed to be attributable to our precise evaluation method and a more sophisticated surgical technique.

Adolescent↗

Plasma-cell tumours of the condyle.

Plasma cell tumours are a group of disorders which are characterized by neoplastic proliferation of atypical plasma cells involved in the production of monoclonal immunoglobulins. Bone pain, renal insufficiency and normocytic-normochromic anaemia are suggestive data for diagnosis. In 12-15% of cases of multiple myeloma, the first manifestation of the disease appears in the jaw bones and oral cavity. Two cases of multiple myeloma affecting the mandibular condyle are presented, and the incidence of oral and maxillofacial lesions is briefly reviewed.

Adult↗

Conservative treatment of unilateral condylar fractures in children: a long-term clinical and radiologic follow-up of 55 patients.

The purpose of this prospectively designed study was the long-term clinical and radiological evaluation of conservatively treated unilateral condylar fractures in children. Fifty-five children aged between 2 1/2 and 9 3/4 years, presenting with a singular unilateral fracture of the mandibular condyle, were treated in a nonsurgical-functional way using an intraoral myofunctional appliance. In the follow-up period, patients were investigated by standardized clinical examination and by evaluation of panoramic radiographs taken immediately post-traumatically, after 6, 12, 24, 48 and 72 weeks, and then yearly through the period of growth. With a satisfactory clinical course in all patients, there was no instance of functional disturbance or mandibular asymmetry after the respective follow-up periods. The radiographs showed a fairly good shape of the condyle (no or only slight condylar deformity) in the 47 patients of the 2-6 year age group. In the eight patients of the 7-10 year age group presenting with a class II or III condylar fracture, healing was characterized by incomplete condylar regeneration, resulting in a moderate condylar deformity in two cases, a definite reduction in condylar neck height in two cases, and a hypertrophic condylar deformity in four cases. The positive results of this study confirm the concept of a nonsurgical-functional approach in children presenting with various types of unilateral fractures of the mandibular condyle. Condylar remodeling was the mode of fracture healing in instances of displaced and dislocated condylar fractures.

Child↗

Type II collagen and aggrecan mRNA expressions in rabbit condyle following disc displacement.

The aim of this investigation was to study the remodelling of cartilage in the mandibular condyle following disc displacement (DD) of the temporomandibular joint (TMJ). Forty adult Japanese white rabbits were used in this study. The right joints of 28 of the 40 rabbits had their discs surgically displaced. Four of the 28 were killed at 4 days or 1, 2, 4, 6, 8 and 12 weeks after surgery. The messenger RNA (mRNA) expression levels of aggrecan and type II collagen in cartilages were measured using in situ hybridization techniques. Results showed that aggrecan mRNA expression reduced in the first week after DD. The expression began to recover after 4 weeks and reached a normal level after 6 weeks. Type II collagen mRNA expression reduced from 4 weeks and the expression recovered after 8 weeks. This suggests that the chondrocyte reacting to the displacement of the TMJ disc, alters its matrix gene expression patterns and it is may be the cause of the shape changes of TMJ after DD.

Aggrecans↗

[Histology of the cartilage of the human fetal condyle].

The Authors have examined with optical microscopy the articular cartilages from the supero-posterior area of the mandibular condyles of ten TMJ of 5 human fetuses. In this study have been shown the cellular components of the 3 outer areas of the condyle. Further it has been pointed out that the fibrous lining of the cartilage is not only composed of collagen fibrils, proteoglycans and fibroblasts but also contains elastic fibers.

Cartilage, Articular↗