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Results for “MANDIBULAR CONDYLE”

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PubMed1990

[Histogenesis and three-dimensional observation on condylar cartilage in prenatal mice].

The present investigation is carried out to study the histogenesis and the three-dimensional interrelationship of the mandibular condyle, mandibular body, angular cartilage and Meckel's cartilage in the C57BL mouse fetuses. The frontal serial sections obtained at 13 to 18 days of gestation (plug day = 0) were used for the histological observation and the digitized area data from the tracings of each specimen were provided for the computer-aided reconstruction. The results were as follows: 1. The primordium of the condylar cartilage appeared in the area of the superio-lateral site of the primordium of the mandibular body at 14.5 days of gestation. 2. After 14.5 days of gestation, the mandibular body developed, covering the primordium of the condylar cartilage, but its developmental process was slightly different between the medial and the lateral site. 3. The condylar cartilage at 16 days of gestation was comparable to carrot-shape. 4. Endochondral bone formation was demonstrated at the most medial portion of the condylar cartilage at 18 days of gestation.

Animals↗
PubMed2004

Neovascularization and bone formation in the condyle during stepwise mandibular advancement.

The aims of this investigation were to identify the temporal expression of vascular endothelial growth factor (VEGF) in the mandibular condyle and to correlate it with the pattern of new bone formation during stepwise mandibular advancement. Two hundred and fifty female, 35-day-old Sprague-Dawley rats were randomly divided into 10 groups, with 10 rats allocated to the single-step bite-jumping subgroup, 10 rats to the stepwise advancement subgroup and five rats to the control subgroup. In the experimental groups, the mandibles were kept in a continuous forward position. The initial stepwise advancement commenced on day 35, whereas the second advancement started on day 65. The rats were sacrificed on experimental days 3, 7, 14, 21, 30, 33, 37, 44, 51 and 60. Sections (7 microm) were cut through the condyle in the parasagittal plane and stained with anti-VEGF antibody. Each section was counter-stained with haematoxylin for observation of the cellular response. The sections were digitized and quantitatively analysed with a computer-assisted image analysing system. The results showed that the initial advancement in the stepwise group led to significantly less expression of VEGF when compared with single advancement. However, the second advancement on day 30 resulted in a significant increase in VEGF expression when compared with the one-step group and the natural growth control group. Thus, it was concluded that changes in the amplitude of mechanical loading, produced by stepwise advancement, have a significant effect on the production of VEGF by the chondrocytes. During the later stages of advancement, more VEGF and more condylar bone was produced.

Analysis of Variance↗
PubMed1981

Condylar cartilage: a scanning electron microscope study of anorganic mammalian condyles.

The mandibular condyles of four mammalian species (sheep, cat, monkey, and human) were rendered anorganic in NaOCl and examined by SEM. A mineralized cartilage front was identified in all specimens on the basis of a comparable morphology of chondrocyte lacunae and a calcospheritic pattern of mineralization. Species-specific differences in the cartilage surfaces were found to exist. The role of this cartilage in condylar remodeling and pathology is discussed. Attention is drawn to the fact that mineralized cartilage was identified on the articular aspect of all adult mammalian anorganic condyles examined.

Animals↗
PubMed2002

Treatment of condyle fracture caused by mandibular angle ostectomy.

A prominent mandibular angle is considered to be unattractive in Asian countries because it gives the face a square and muscular appearance. Successful correction by angle ostectomy has been reported, but one of the serious complications of angle reduction ostectomy is fracture of the mandibular condyle. If the ostectomy line is misdirected vertically, the condyle may be fractured. The authors experienced two cases of condylar fracture during angle reduction. Case 1 was a pulled-out condylar fracture, where an L-shaped miniplate was then attached by external approach, and intermaxillary fixation (IMF) with arch bar was used on postoperative day 14. With release of the IMF, a systematic approach for a jaw-opening exercise was begun. On postoperative day 21, the elastics were placed to assist in guiding protrusion of the mandible anteriorly 24 hours a day. After postoperative day 28, it was possible to completely abandon daytime elastic fixation. The exercise was modified to lateral movement. Case 2 was green-stick condylar fracture, with the IMF with arch bar applied on postoperative day 10. After releasing the IMF, the exercise involved the daily use of several tongue blades, and range of motion increased by wedging additional blades until postoperative day 21. More aggressive stretching was continued with 22 blades on postoperative day 28. On the removal of the arch bar, the occlusion was stable and followed by more aggressive stretching and physical therapy. Both cases were successfully restored and had good results. The authors believe the exercise protocols and algorithms they used may serve as a standard procedure of treatment in condylar fracture caused by angle ostectomy.

Adult↗
PubMed1983

Mandibular growth, condyle position and Fränkel appliance therapy.

A statistical evaluation of condyle position and mandibular length changes in 10 patients after one year of Fränkel appliance therapy, finding the condyle forward on the eminence in 4 of them. Large variations were found in mandibular growth, with no significant difference from the means of patients treated with the Edgewise appliance.

Activator Appliances↗
PubMed1996

Age-related changes in the localization of glycosaminoglycans in condylar cartilage of the mandible in rats.

There is little information available regarding the morphological and biomolecular characteristics of mandibular condylar cartilage. The purpose of this study was to determine the age-related changes in the morphology and immunolocalization of glycosaminoglycans (GAGs) in mandibular condyles. The mandibular condylar cartilages from 4-, 8-, 16-, 32-, and 64-week-old Wistar male rats were examined to verify the localization of chondroitin-4-sulfate (Ch-4S), chondroitin-6-sulfate (Ch-6S) and keratan sulfate (KS) using an indirect immunofluorescent technique with three monoclonal antibodies for glycosaminoglycans, 2-B-6, 3-B-3 and 5-D-4, respectively. Morphologically, the condylar cartilage was a growth cartilage during growing periods, began to differentiate into articular cartilage from the central area of 16-week-old condyles, and became mature articular cartilage at 32 weeks of age. A regional difference was found in the morphological features and distribution of GAGs between the anterior, central, postero-superior and posterior areas of the condyles at each age. The immunohistochemical localizations of these three glycosaminoglycans showed age-related, morphology-dependent changes, from growth cartilage to articular cartilage-like cartilage. Immunoreactions for all of the antibodies decreased progressively with age in the interterritorial matrix, while the pericellular and territorial matrix in the condylar cartilage of the mandible maintained relatively higher immunoreactivity. In conclusion, age-related and regional differences in the localization of glycosaminoglycans Ch-4S, Ch-6S, and KS were found in the mandibular condyles in rats, and these changes are believed to be related to functional and developmental requirements.

Aging↗
PubMed1990

Morphology of the condyles and mandibular fossa as seen by computed tomography.

Computed tomography allows detailed three-dimensional examination of the hard and soft tissue of the temporomandibular joint. The morphology of the mandibular fossa and the condyles together with the horizontal and vertical condylar inclinations was determined in 25 patients with temporomandibular joint dysfunction and 29 controls by use of axial and coronal computed tomography projections. The shape of the condyle was evaluated according to its general appearance. The temporomandibular joint measurements obtained by computed tomography were in good agreement with morphologic studies performed on dry skulls and autopsy material.

Adolescent↗
PubMed1993

Avascular necrosis of the mandibular condyle-pathogenesis and concepts of management.

A vascular necrosis is a well-recognized pathologic entity in orthopedic surgery which most commonly affects the femoral head. Avascular necrosis of the mandibular condyle has been recognized recently, although controversy exists as to the appropriate methods of diagnosis and treatment. We present a discussion of the pathogenesis of avascular necrosis derived from the orthopedic literature and its extrapolation to management of the temporomandibular joint in the form of decompression corticotomy of the condyle by two techniques.

Compartment Syndromes↗
PubMed2005

Runx2 regulates endochondral ossification in condyle during mandibular advancement.

Runx2 is a transcription factor prerequisite for chondrocyte maturation and osteoblast differentiation. We tested the hypothesis that Runx2 is responsible for signaling chondrocyte maturation and endochondral ossification in the condyle during mandibular advancement. Fifty 35-day-old Sprague-Dawley rats were fitted with functional appliances for 3, 7, 14, 21, and 30 days. Experimental animals with 50 matched controls were labeled with bromodeoxyuridine for evaluation of the invasion of chondroclasts and osteoblasts into condylar cartilage. Mandibular advancement elicited Runx2 expression in condylar cartilage, and subsequently led to an expansion of type X collagen domain in the hypertrophic layer. Stronger Runx2 mRNA signals in subchondral bone corresponded with the increase in the recruitment of osteoblasts and chondroclasts, which preceded the increase of new bone formation in the condyle. Thus, Runx2 mediates chondrocyte terminal maturation and endochondral ossification in the mandibular condyle in response to mandibular advancement.

Animals↗
PubMed2006

Disc-condyle Relationships during Class II Treatment with the Functional Mandibular Advancer (FMA).

OBJECTIVE: The objective of this study was to verify the effects of treatment to correct Class II malocclusion with the Functional Mandibular Advancer (FMA) on the relative positions of the articular disc and mandibular condyle. In particular, we aimed to find out whether the disc-condyle relationship changed between baseline and post-treatment, in temporomandibular joints initially exhibiting a physiological relationship and alternatively, in temporomandibular joints initially presenting anterior displacement of the articular disc. PATIENTS AND METHODS: Treatment progress in 15 patients was monitored at defined points in time by manual structural analysis (MSA) and magnetic resonance (MR) imaging. The disc-condyle relationship was assessed by examining the parasagittal MR images made up of three slices each (lateral, central, medial) taken in habitual intercuspation and maximum-open mouth position. The MR images were metrically analyzed to determine the sagittal positional relationship of the articular disc and mandibular condyle using two methods on the central slices of the images taken in closed-mouth position. MSA was used in particular to determine the disc-condyle relationships and to metrically record the extent of active movement of the mandible during mouth opening, protrusion, laterotrusion, and retrusion. RESULTS: Comparison of baseline and post-treatment findings revealed that none of the joints exhibited a treatment-induced deterioration in the disc-condyle relationship, while the relationship improved in five joints. After categorization of the joints according to groups according to disc position, metric analysis of the MR images showed significantly-improved post-treatment disc positions in the joints that had initially exhibited anterior disc displacement. Post-treatment findings for maximum-open mouth position, protrusion, and laterotrusion corresponded to the baseline values recorded before bite-jumping, and the extent of maximum active retrusion increased significantly. CONCLUSIONS: Functional jaw orthopedics for correction of skeletal Class II with the rigid fixed FMA leads to side-effects reflected in the disc-condyle relationship in the temporomandibular joints: no adverse effects were observed in joints presenting an initial physiological disc-condyle relationship, whereas the disc position may improve in joints with initial partial or total anterior disc displacement. In comparison with the baseline findings, we observed no post-treatment restriction in the extent of maximum mouth opening, protrusion, and left and right laterotrusion. Maximum active retrusion increased due to the treatment. MR imaging and MSA only partly cover the same aspects of temporomandibular joint diagnostics.

Adolescent↗
PubMed1995

Experimental occlusal interferences. Part III. Mandibular rotations induced by a rigid interference.

A rigid intercuspal interference (minimum mean height of 0.24 mm) was placed on either the right or left mandibular second premolar and first molar of 12 subjects. During brisk and forceful biting on the interference, rotational electrognathography measured maximum torque of the right and left mandibular condyles in the frontal and horizontal planes of orientation. All subjects showed frontal plan upward rotation (mean of 0.7 degrees) of the mandibular condyle contralateral to the interference. In 33% of the subjects there was no horizontal plane backward rotation. In 58% of the subjects there was horizontal plane backward rotation (mean of 0.5 degrees) of the mandibular condyle ipsilateral to the interference, and in one subject (8%) there was backward horizontal plane rotation (0.1 degree) of the mandibular condyle contralateral to the interference. It was inferred that the masseter muscle, ipsilateral to the interference, generated negative work in order to decelerate frontal plane 'unseating' of the mandibular condyle ipsilateral to the interference. It was inferred that the masseter muscle, contralateral to the interference, produced positive work in order to accelerate frontal plane 'seating' of the mandibular condyle contralateral to the interference. Finally, it was speculated that the impact forces of frontal plane 'seating' of the mandibular condyle, contralateral to the interference, might lead to 'vacuum sticking' of the temporomandibular joint disc because of the formation of negative hydrostatic pressures.

Adult↗