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Aplasia of the mandibular condyle is extremely rare when not seen as a part of a syndrome. A case, apparently with no soft tissue aberrations, is described and a possible connection with the hemifacial microsomia syndrome is discussed.
In 42 patients, the mandibular protrusion and lateral excursions after fractures of the mandibular condyles were recorded using the "arrow-angle" registration method. The opening of the mouth was measured directly. The restriction of the mandibular mobility did not always correspond to fracture-mechanical expectations. Mobility improved as the time passed after the trauma, without the movement pattern changing.
The cartilagenous tissue of mandibular condyles of newborn mice contains progenitor cells as well as young and mature chondrogenic cells. During in vitro cultivation of the tissue, progenitor cells undergo osteogenic differentiation and form new bone (Silbermann, M., D. Lewinson, H. Gonen, M. A. Lizarbe, and K. von der Mark. 1983. Anat. Rec. 206:373-383). We have studied the expression of genes that typify osteogenic differentiation in mandibular condyles during in vitro cultivation. RNAs of the genes for collagen type I, osteonectin, alkaline phosphatase, and bone gla protein were sequentially expressed in progenitor cells and hypertrophic chondrocytes during culture. Osteopontin expression peaked in both the early and the late phase of the differentiation process. The data indicate a distinct sequence of expression of osteoblast-specific genes during osteogenic differentiation and new bone formation in mandibular condyles.
Cases of mandibular condyle fracture have been reported in patients in evolutive age. Conservative and rehabilitative treatment was carried out with excellent anatomofunctional results in the course of growth.
The secondary cartilage of the mandibular condyle is considered to be adaptive to functional factors. In the last decades, growth factors have also been shown to be potent regulators of cartilage metabolism. Moreover, it has been suggested that growth factors may differentially regulate the growth of primary and secondary cartilages. However, only a few studies have made a direct comparison of the effects of growth factors on both cartilages. Therefore, the aim here was to compare the effects of FGF-2 on secondary cartilage of the mandibular condyle and primary cartilage of the femoral head from 4-day-old rats in vitro. Cartilages were cultured for 1, 7 and 14 days with 0 and 100 ng/mL FGF-2. We evaluated the effects of FGF-2 on growth, tissue organisation, DNA and glycosaminoglycan (GAG) synthesis and GAG and collagen content. With FGF-2, the morphology of the mandibular condyles changed and the GAG and collagen contents were reduced. However, the growth of the mandibular condyles was not affected. On the contrary, the growth of the femoral heads was strongly reduced due to an inhibition of chondrocyte hypertrophy. In both cartilages, FGF-2 stimulated DNA synthesis in short-term cultures and reduced it in long-term cultures. In conclusion, FGF-2 had a larger effect on the metabolism of the mandibular condyles as compared to the femoral heads. However, the growth of the femoral heads was strongly reduced while that of the mandibular condyles was not affected.
Bilateral bifid mandibular condyle is a rarely seen malformation. The aetiology of bifid condyle is not completely understood, although developmental anomaly, traumas, condylar fracture, teratogenic embryopathy and surgical condylectomy may all be causative factors. Although a few studies on human dried skulls tried to shed light on this entity it remains obscure. As most bifid condyle subjects have no complaint related to temporamandibular joint(TMJ), the cases are generally diagnosed through incidental radiographic findings. The case of a 54-year-old female is presented. In a panoramic radiograph obtained after a clinical examination, bilateral bifid mandibular condyle was observed. The open-closed lateral radiograph of the TMJ (obtained using the TMJ-specific program of the panoramic device) demonstrated duplication of the right and left condyles. In order to better evaluate the TMJ morphology and to eliminate pathologies such as fractures that might be missed with conventional radiographs, a computed tomography scan was also obtained. The joint head orientation was observed in the mediolateral direction. The case is discussed in the context of the relevant literature. Until large population-based studies are undertaken and further experimental studies are performed, bifid condyle will remain an incidental finding of anatomic variation rather than a clinically informative observation.
The purpose of the present study was to investigate histologically and ultrastructurally the effect of prostaglandin E1 (PGE1) on the development and growth of the rat mandibular condyle in organ culture. The mandibular condyles of rats were divided into 5 groups (Groups 1-5) for light microscopy and 5 groups (Groups I-V) for electron microscopy. In Groups 1 and I, the mandibular condyles were removed from rats 1, 2, 4, 6 and 8 days after birth. In Groups 2 and II, 3 and III, 4 and IV, and 5 and V, the mandibular condyles were removed from rats immediately after birth and were cultured for 1, 2, 4, 6, and 8 days in the four media, namely BGJb, BGJb with 1% ethanol, BGJb with 0.5 micrograms of PGE1/ml, BGJb with 5 micrograms of PGE1/ml, respectively. The mandibular condyles of 5 groups (Groups 1-5) were examined histologically at 1 to 8 days, and the mandibular condyles of the other 5 groups (Groups I-V) were examined ultrastructurally at 4 and 6 days. 1. Light Microscopic Observation. i) Group 1 (in vivo) The zones of articular surface, proliferation, differentiation and hypertrophy of the mandibular condyle showed normal development. ii) Group 2 (BGJb) and Group 3 (BGJb+1% AL) The zones of proliferation and differentiation displayed a slight decrease in cell number compared with those of Group 1. iii) Group 4 (BGJb+0.5 micrograms PGE1) and Group 5 (BGJb+5 micrograms PGE1) The zone of proliferation showed a moderate decrease in cell number and in thickness compared with those of Groups 2 and 3. The zone of differentiation exhibited a marked decrease in cell number and in thickness, so that the level of the zone of hypertrophy moved upwards and close to the zone of proliferation. 2. Electron Microscopic Observation i) Group I (in vivo) The cells of the zones of articular surface, proliferation, differentiation and hypertrophy showed normal development in their cell organella such as mitochondria, rough surfaced endoplasmic reticulum and Golgi apparatus. ii) Group II (BGJb) and Group III (BGJb+1% AL) The cells of the zones of proliferation, differentiation and hypertrophy exhibited poor development in their cell organella compared with those of Group I. iii) Group IV (BGJb+0.5 micrograms PGE1) and Group V (BGJb+5 micrograms PGE1). The cells of the zone of proliferation exhibited poor development in their cell organella compared with those of Groups II and III. Furthermore, the zone of proliferation contained the fragments of cells in its intercellar areas.(ABSTRACT TRUNCATED AT 400 WORDS)
Bifid mandibular condyle, usually diagnosed on routine radiographic examination, is described in the literature as a rare entity. Its cause is controversial, and it has no predilection by sex or ethnic background. Dental professionals should have some knowledge of this anatomic abnormality, as well as its implications for function and appropriate treatment modalities, so that they can be alert to this potential diagnosis. This paper reports an unusual case of bifid mandibular condyle with possible traumatic cause, with emphasis on the radiographic and tomographic findings.
CD44 is a multifunctional adhesion molecule that binds to hyaluronan (HA), type I collagen, and fibronectin. We investigated localization of CD44 and HA in mandibular condylar cartilage compared with the growth plate and the articular cartilage, to clarify the characteristics of chondrocytes. We also performed Western blotting using a lysate of mandibular condyle. In mandibular condyle, CD44-positive cells were seen in the surface region of the fibrous cell layer and in the proliferative cell layer. Western blotting revealed that the molecular weight of CD44 in condyle was 78 to 86 kD. Intense reactivity for HA was detected on the surface of the condyle and the lacunae of the hypertrophic cell layer. Moderate labeling was seen in cartilage matrix of the proliferative and maturative layer. Weak labeling was also seen in the fibrous cell layer. In growth plate and articular cartilage, HA was detected in all cell layers. However, chondrocytes of these cartilages did not exhibit reactivity for CD44. These results suggest that chondrocytes in the mandibular condylar cartilage differ in expression of CD44 from those in tibial growth plate and articular cartilage. Cell-matrix interaction between CD44 and HA may play an important role in the proliferation of chondrocytes in the mandibular condyle.
The effects of fluoride on the mandibular condyles in growing newborn rats were studied by histological, histometrical and fluoride electrode methods. The layer of cartilage of the mandibular condyle in the animals administered 5, 15, 25 and 35 mg/kg of fluoride for 3 weeks displayed a significant increase in thickness when compared with that of the mandibular condyle in the control animals. The thickening of the cartilage layer was proportioned to the amounts of fluoride administered. The volumetric density of cancellous bone of the condyle in the animals administered 25 and 35 mg/kg of fluoride also increased significantly when compared with that of the condyle in the control animals. The trabeculae of cancellous bone of the condyle in these animals contained large amounts of osteoid. The cancellous bone of the condyle in the animals of the four fluoride groups showed a significantly higher fluoride concentration when compared with that of the condyle in the control animals. The fluoride concentration proportionally increased with the amounts of fluoride administered. The results of the present study indicate that the morphologic changes and the fluoride concentrations in the mandibular condyles of rats receiving fluoride were closely correlated with each other.
Bifid mandibular condyle is an infrequent and normally asymptomatic morphological alteration of the mandibular condyle. Although the underlying cause is not clear, a number of theories have been proposed, including teratogenic effects in the embryo, vascular alterations during condyle development, and condylar remodeling following fracture. Since Schier first described this anomaly in 1948 in live individuals, further cases have been documented in the literature. We present a new case of bilateral bifid condyle. The disorder was asymptomatic and constituted a casual finding in a young male presenting for the surgical extraction of two impacted molars.
Primary and secondary cartilages differ in embryonic origin and in histological organization, and are generally considered to have a different mode of growth. However, few studies have directly compared the two types of cartilage of the same animal at the same age. Therefore, we analysed several histological and biochemical differences between secondary cartilage of the mandibular condyle and primary cartilage of the femoral head of 4-d-old rats. We evaluated the tissue organization, the level of DNA and glycosaminoglycan (GAG) synthesis, and the GAG and collagen content. The expression of collagen types I, II and III and of receptors for insulin-like growth factor (IGF)-I, fibroblast growth factor (FGF), and transforming growth factor (TGF)-beta were investigated by immunohistochemistry. The ex vivo DNA and GAG synthesis as well as the GAG content of femoral heads were much higher than that of mandibular condyles. Mandibular condyles expressed both collagen types I and II, while femoral heads expressed only type II collagen. In the mandibular condyles, receptors for IGF-I, FGF, and TGF-beta were observed mainly in the superficial layers, whereas they were found throughout the entire femoral head. In conclusion, major differences were found between both types of cartilage, which might be related to their specific functional demands.
This study is concerned with the classification of mandibular condyles on the basis of the shape of their frontal section. In a previous work, Yale et al. [Oral Surg. 16: 572-577, 1963] had divided mandibular condyles into 4 groups: flat, convex, angled, and round. The distinction between them had been found upon simple inspection. In this paper a quantitative method is proposed, in which mandibular condyles may be classified into the same 4 groups according to inequalities concerning measurable parameters of their frontal section. The process is greatly facilitated by the use of a programmable computer. The proposed method has been applied to a sample of 254 human mandibles (hence 508 condyles); the percentage of each group has been the following; flat 11%; convex 38%; angled 41%, and round 10%. It is plausible to surmise that the quantitative character of the proposed method may be of significant use in oral radiology as well as in anthropological research.
A total of 356 patients with mandibular condyle fractures were studied regarding associated dental injuries. One third of the patients had injured teeth, on average, 3.7 teeth had been injured per accident. Dental traumas were distributed equally between the anterior (incisors and canines) and posterior teeth (premolars and molars) in both jaws. In unilateral condylar fracture cases maxillary dental injuries involved more often premolars and/or molars of the fracture side than those of the nonfracture side. The mean number of dental traumas in the mandible was higher in cases of simultaneous mandibular body fracture than without, whereas the presence of mandibular body fracture did not affect number of associated dental injuries in the maxilla. The dental injuries were mostly to hard tissue (78%), which were commonest in men, 20 to 29 years of age, and in victims of violence or fall accidents. Severe dental injuries in association with mandibular condyle fractures were more common in accidents due to traffic and miscellaneous causes than in those due to violence. Severe dental injuries were more often encountered when simultaneous mandibular body fracture was present than when it was not and more so in bilateral than unilateral condylar fracture cases. The most important factor correlating with the severity of dental injuries was the presence of bilateral condylar fracture.
Reconstruction of the mandibular condyle with costochondral grafts (CCGs) in children may result in overgrowth at the reconstructed side of the mandible. In this study we report on the effects of functional stimuli on growth and morphology of growth plates of CCGs used for immediate mandibular condyle replacement in 10 juvenile pigs. The mandibular condyles were resected unilaterally and immediately reconstructed with autogenous CCGs. Another CCG was placed submuscularly on one tibia. The lengths of both CCGs and of one rib before resection were measured at operation and 12 weeks later. The grafts were labelled with intraperitoneal injections of oxytetracycline and alizarin eight and 12 weeks postoperatively, respectively. The extent of growth of the CCGs in the two environments was similar, so we concluded that the functional stimuli in the TMJ environment had only a minor influence on the extent of growth of the CCGs. The morphology of the growth plate of the CCGs had changed considerably.
Bilateral bifid mandibular condyles are a rare anomaly that had previously been described only by Hrdlicka in material from skull collections. We present here three cases of bilateral bifid mandibular condyles in patients who sought treatment for other reasons. The radiographic appearance of this anomaly and its embryology are discussed.
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A case of chondrosarcoma of the mandibular condyle is described. With carefully taken tomographs, a diagnosis of chondrosarcoma of the mandibular condyle can be made with some degree of certainty, on radiological evidence alone. Chondrosarcomata of the mandibular condyle may manifest with the typical symptoms of the temporomandibular joint dysfunction syndrome. Tumours of the condyle can reach a large size without producing clinically obvious swellings. The literature pertaining to chondrosarcoma of the mandibular condyle is reviewed.