Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MANDIBULAR CONDYLE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed1999

Differential expression of fibroblast growth factor receptor-1, -2, and -3 and syndecan-1, -2, and -4 in neonatal rat mandibular condyle and calvaria during osteogenic differentiation in vitro.

Fibroblast growth factors (FGFs) play important roles in the control of skeletal cell growth and differentiation. To identify the mechanisms of regulation of FGF actions during chondrogenesis and osteogenesis, we investigated, by immunohistochemistry, the spatiotemporal expression of the high-affinity FGF receptors (FGFR-1, -2, and -3) and coreceptors (syndecans-1, -2, and -4) in newborn rat condyle and calvaria during chondrogenesis and osteogenesis in vitro. During chondrogenesis at 4 days of culture, condyle chondrocytes showed weak FGFR-1, FGFR-2, and syndecan-1 immunoreactivity; stronger syndecan-2 expression; and marked FGFR-3 and syndecan-4 immunolabeling. At a later stage (i.e., 9 days of culture), FGFR-1, -2, and -3 were coexpressed with syndecan-4 in chondrocytes. Condyle progenitor cells located in the condyle perichondrium initially expressed strong syndecan-2 and -4 and weak syndecan-1 labeling, whereas no FGFR was detectable. When these cells differentiated into osteoblasts, they expressed syndecan-2 and -4 coincidently with FGFR-1, -2, and -3 at 9 days of culture. In newborn rat calvaria, syndecan-1, -2, and -4 were coexpressed mainly with FGFR-1 and -2 in osteoblasts. In the two models, treatment with FGF-2 (100 ng/mL) at 4-9 days of culture increased cell growth and decreased glycosaminoglycan or collagen synthesis, respectively, suggesting interactions of FGF-2 with distinct FGFRs and syndecans during chondrogenesis and osteogenesis. The coincident or distinct spatiotemporal expression pattern of FGFRs and syndecans in chondrocytes, progenitor cells, and osteoblasts represents a dynamic mechanism by which FGF effects on skeletal cells may be controlled in a coordinate manner during cartilage and bone formation in vitro.

Animals↗
PubMed1991

Increased horizontal angle of the mandibular condyle in abnormal temporomandibular joints. A magnetic resonance imaging study.

The horizontal condylar angle was measured in axial magnetic resonance images of normal and abnormal temporomandibular joints (TMJs). The average condylar angle in the normal joints was 21.2 degrees. In joints with disk displacement with reduction it was 29.7 degrees; joints with disk displacement without reduction, 33.5 degrees; and in joints with degenerative joint disease, 36.5 degrees. There were statistically significant differences between all four groups. Thus the condylar angle seemed to be increasingly larger with more advanced pathologic changes related to internal derangement and degenerative disease in the joint. The reason for the larger condylar angle in the abnormal joint was unclear. Joints with a larger condylar angle might have a greater tendency for internal derangement and degenerative joint disease to develop. Another possible explanation could be that remodeling associated with internal derangement and degenerative joint disease might result in a larger condylar angle. Further studies with longitudinal observations are needed to determine whether a causal relationship exists between the changes of the joint and a large condylar angle.

Adult↗
PubMed1999

Costochondral grafts replacing the mandibular condyle.

OBJECTIVE: The purpose of this study was to determine the success rate of costochondral bone grafts used to replace absent or nonfunctioning temporomandibular joints and the subsequent growth of these grafts when placed in young children. DESIGN: This is a retrospective study of all cases with adequate follow-up records that were treated at the Craniofacial Centre at Toronto's The Hospital for Sick Children from 1974-1986. A total of 55 patients were evaluated, of whom 13 were growing children. RESULTS: The findings suggest that there was increased success when surgery was performed at an early age. Poorer results were achieved when previous surgery had been performed or when pathology was present. Growth of the graft did not always equal the growth of the "normal" side, but in most cases a satisfactory symmetry was achieved. Several cases exhibited excessive overgrowth. CONCLUSIONS: Surgery at 4 to 5 years of age will alleviate the impact of a severe facial deformity on the child during the early school years, when self-esteem is fragile and patterns of social interactions are developing. Development of the dentition is better if the jaw relationship is close to normal at an early age. It would appear that early temporomandibular joint (TMJ) construction by costochondral grafting is, at present, the method of choice for severe hemifacial microsomia.

Adolescent↗
PubMed1984

Studies on hormonal regulation of the growth of the craniofacial skeleton: III. Effects of 24,25 (OH)2D3 on cartilage growth in the mandibular condyle of suckling mice.

This study examined the influence of 24,25 (OH)2D3, an active metabolite of vitamin D, on the growth and development of cartilage cells in condylar cartilage of suckling mice. It became evident that when the hormone was administered even at high doses, it did not significantly affect the incorporation of [3H]thymidine, but led to a marked decrease in the number of both chondroblasts and hypertrophic chondrocytes. At the same time, condyle of hormone-treated mice reached an increase in the number of mesenchymelike cells within the chondroprogenitor zone. High values of correlation were noted between the overall dimensions of the condylar cartilage and those of the chondroblastic and hypertrophic zones. The hormone also significantly reduced the degree of matrix metachromasia (indicative of proteoglycan content) and concomitantly altered the mineralization pattern of the cartilaginous matrix. This study indicates that in young animals increased doses of 24,25(OH)2D3 do not affect the proliferative activity of chondroprogenitor cells yet possess an inhibitory effect upon the capacity of the latter cells to differentiate into chondroblasts. The hormone also seems to affect the already differentiated cells--chondroblasts and hypertrophic chondrocytes--both structurally as well as metabolically. In so doing, this metabolite of vitamin D affects the normal process of endochondral bone formation in one of the mandible's main growth sites. Thus, in the developing animal, elevated concentrations of 24,25(OH)2D3 may impair the growing mandible's ability to achieve its normal size and shape.

24,25-Dihydroxyvitamin D 3↗
PubMed1992

Accuracy of quantification of mandibular condyle displacement in digitally subtracted linear tomograms.

Using a TMJ skeletal phantom, we assessed validity and reliability of digitally subtracted linear tomographic images to quantify condylar position changes. Horizontally corrected frontal and lateral tomographic images were made with the condyle in a 'centred' position and displaced by 1, 2 and 3 mm increments in two of three directions (inferior, and posterior, or lateral). Film images were sequentially subtracted and then randomized so that observers were blinded to the amount and direction of condylar movement. Averages of three measurements of the dark bands representing condylar shifts were made using a digitizing tablet. The study utilized a nested design where the series of film images was subtracted twice and each subtraction was read twice by two examiners. We repeated the study with a second series of films treated in an identical manner. Average differences from expected values were similar for frontal and lateral techniques and all directions and increments of displacement. Typical average difference for any increment was less than 0.1 mm. Standard deviations in measures were similar across techniques and increments and were typically less than 0.1 mm. Significant variation in the absolute value of differences between measured and expected values by direction of condylar displacement was attributed to greater accuracy of registration on the vertical axis for frontal images. A significant source of variation in the study design element 'film set' was attributed to errors in repositioning the phantom.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1987

Relationship between the mandibular condyle and the occlusal plane during hominid evolution: some of its effects on jaw mechanics.

A selection of mandibles from recent higher primates, fossil hominids, and hominoids has been studied from photographs of skulls, reproductions, and material published by others, all viewed in the sagittal plane. Tracings of each mandible were constructed so that the dentitions were all scaled to the same length (d) and superimposed. The (scaled) positions of the articular surfaces of the condyles (J = joint point) were compared. The height of each J point above the scaled dentition (h = effective condyle height) and its distance behind the dentition (r = effective ramus width) were compared. With very few exceptions d greater than r greater than d/2. There was a poor correlation between r and the amount of prognathism. The position of the J point with respect to the occlusal plane was different for different groups within the material analysed and could prove to be a useful tool to help improve the reconstruction of fragmented fossil material. Some examples are given. A. afarensis and Homo habilis shared a low and anterior J point (r approximately d/2). The later australopithecines evolved a high and anterior J point, whereas that of Homo erectus was raised and displaced posteriorly (r approximately 3d/4). The value of r was increased to d in the Neanderthals, and recent man has moved the J point forward again. The effect of the position of the J point, the slope of the preglenoid plane, and the curve of Spee on the relationship between upper and lower postcanines when the jaw is opened and then closed to process food have been analysed. The results show that the position of the J point affects the way in which the mandible moves, and this may be related to changes in diet during evolution.

Animals↗
PubMed1993

Insulin-like growth factor I accelerates proliferation and differentiation of cartilage progenitor cells in cultures of neonatal mandibular condyles.

The present study examined the effect of exogenous IGF-I on growth and development of neonatal cartilage of the mandible condyle. Condylar cartilage was cultured as organ culture. The explants were cultured on top of collagen sponges in medium containing 2% fetal calf serum and were treated with IGF-I at doses ranging from 3.25 to 26 nmol/l for up to six days. IGF-I was found to increase significantly the uptake of [3H]-thymidine and [35S]-sulfate in a dose-related manner. The enhanced cellular proliferation, along with the increased synthesis of proteoglycans, resulted in a substantially larger mass of tissue in the organ culture system. The nature of the IGF-I stimulative effect was further studied through the use of a tissue culture system whereby a separated chondroprogenitor zone is cultured under conditions which favor its development at first into cartilage and then into bone. Using this culture system, we could show that IGF-I induces merely the de novo chondrogenesis process. This was reflected in the appearance of relatively large amounts of cartilage specific antigens such as type II collagen, cartilage proteoglycans, chondrocalcin and 100 KDa protein. Yet, no bone specific antigens were significantly increased, as is the case with GH effects. These results indicate that IGF-I is a strong chondrogenetic agent. But, unlike growth hormone, it does not seem to stimulate bone formation.

Analysis of Variance↗
PubMed2004

Peripheral giant cell granuloma of the mandibular condyle presenting as a preauricular mass.

Preauricular mass is a common symptom for patients presenting to the otorhinolaryngologist with parotid disease. Some rare extraparotid lesions, originating from the temporomandibular joint and the mandible itself, also share the same localization and therefore are to be taken into consideration for the differential diagnosis with parotid lesions. Giant cell granuloma (GCG) was first described by Jaffe in 1953. Peripheral GCG (PGCG) is an exophytic soft tissue lesion originating from the periodontal ligament and periosteum. It is located only within the oral cavity. Central GCG (CGCG) is an uncommon benign fibro-osseous lesion generally presenting as an expansible mass with cortical bone defect. It is generally located in the mandible. The brown tumor of hyperparathyroidism and giant cell tumor must be ruled out because of the microscopic similarities of these lesions. The first case of PGCG of the mandible condyle is presented, and attention is drawn to mandibular diseases for the differential diagnosis of the preauricular mass.

Adult↗
PubMed1996

Enhanced osteonectin expression in the chondroid matrix of the unloaded mandibular condyle.

Osteonectin provided a spatial and temporal marker for proliferating and differentiating chondrocytes, and during the chondroid matrix formation. The goal of this investigation was to examine early cellular and molecular regulation of mandibular growth. Unloading was induced by anterior functional mastication. The proliferative activity measured by tritiated thymidine incorporation increased 8. 3-fold at 24 hours compared with the corresponding control group. Mandibular unloading for 24 hours increased osteonectin mRNA expression 60% in the condyle over the corresponding control group. Microscopic inspection of the condyle demonstrated osteonectin immunostaining of proliferating, early hypertrophic chondrocytes, and the chondroid matrix across the sagittal section in an anterior-posterior direction. An increasing gradient intensity from a medial-superior to posterior direction was produced with treatment in direct contrast to the control group. The posterior chondroid matrix immunostaining increased 11.7-fold (P = 0.038) after 24 hours treatment over a corresponding control group. Unloading of the mouse mandible caused an increased cellular proliferation, a coincident increase of osteonectin mRNA, and a subsequent increased secretion of the osteonectin protein in the chondroid matrix formation.

Animals↗
PubMed1989

Ultrastructural changes associated with weaning in the mandibular condyle of the rat.

To determine the postnatal structural changes due to increasing articular activity, we have compared the development of the posterior and posterosuperior superficial layers of the rat mandibular condylar cartilage by electron microscopy. In contrast to the uniform development posteriorly, the posterosuperior articular zone showed an extensive remodelling process with collagen breakdown and replacement between the ages of 21 and 28 days, i.e. during weaning. Enlarged spheroid fibroblasts contained numerous micropynocytotic vesicles, collagen debris enclosing vacuoles and a nuclear fibrous lamina enveloping the nucleus; abundant electron-dense amorphous material was present in the matrix as well as covering the surface. An increased number of metabolically active fibroblasts was supplied by the mesenchymal stem cells of the underlying chondrogenic zone. The adaptation process resulted in the replacement of small randomly oriented collagen fibers by large compact bundles running parallel to the glenoid fossa, providing protection to the condyle against excessive wear and tear during incisal biting and grinding. The direct local relationship between (ultra) structure and functional load can be utilized in experimental research on the role of biomechanical forces in mandibular condylar growth and development.

Animals↗
PubMed1990

Mandibular condyle lesions, jaw movements, and occlusal status in 15-year-old children with juvenile rheumatoid arthritis.

The purpose was to determine the number and severity of lesions in the temporomandibular area and their association with occlusal status and mandibular movements in 15-yr-old children afflicted with juvenile rheumatoid arthritis (JRA). The series comprised 121 JRA children, 78 girls and 43 boys, and a control group of 104 schoolchildren, 70 girls and 34 boys, taken for clinical examination. Of the JRA children, 55% had roentgenologically detectable lesions in the TMJ area. Lesions were found in 60% of the girls and in 42% of the boys, the ratio thus being 3:2. The largest group had grave lesions (48%), the second largest displayed flattening of the condyle (43%) and the smallest a flattened condyle with a minor lesion (9%). There were more bilateral lesions in the children with the severest lesions. Tendencies for Class II malocclusion, small vertical overbite and open bite were visible in the JRA children. Reduced maximal opening capacity, maximal protrusion, lateral movements of the mandible and pain in the TMJ area proved to be reliable signs predicting temporomandibular joint involvement in JRA children. Maximal mouth opening capacity was significantly restricted in the patients showing condylar lesions as compared with patients having no lesions or with controls. JRA children should be divided according to sex and the severity of the lesions. The JRA children without TMJ lesions had normal values for mandibular movements and were thus comparable to healthy children.

Adolescent↗
PubMedDate not supplied

A 5-year follow-up of occlusal status and radiographic findings in mandibular condyles of the elderly.

PURPOSE: The aim of the present 5-year follow-up was to clarify the nature of occlusal support status and radiographic changes in condyles of the elderly, and the association between these two variables. MATERIALS AND METHODS: The present study is part of a comprehensive medical survey of a random sample born in 1904, 1909, and 1914. A total of 364 subjects living in Helsinki participated in the dental part of the examination during 1990 to 1991, and after 5 years a total of 103 were reexamined. Comprehensive data on occlusal support status were available for 94 subjects, and radiographic data were available for 88 subjects. Occlusal support status was assessed on the basis of the Eichner index, radiographic changes were assessed from panoramic radiographs, and symptoms of temporomandibular disorders were assessed using Helkimo's anamnestic index. RESULTS: The most frequent radiographic finding in the mandibular joint was flattening of the articular surface of the condyle associated with osteoarthrosis, found at baseline in 17% and during follow-up in 13% of the subjects. During the 5-year follow-up, Eichner index for natural dentition remained unaltered in 94% of the subjects and in 85% of the subjects when removable dentures were included. There were no radiographic changes in 92% of the cases. No differences based on age or gender were found. A logistic regression model revealed associations between the selected baseline factors. The odds ratio for baseline Helkimo's anamnestic index was 4.1, 5.7 for Eichner index with the support of removable dentures, and 356 for radiographic findings. CONCLUSION: Radiographic changes in condyles of elderly people were small during the 5-year follow-up, but baseline radiographic findings, Helkimo's anamnestic index, and Eichner index with removable dentures were risk factors for radiographic findings at the end of the follow-up.

Age Factors↗
PubMed2002

Growth of the mandible after replacement of the mandibular condyle: an experimental investigation in Macaca mulatta.

PURPOSE: The study goal was to investigate growth of the mandible after temporomandibular joint reconstruction in juvenile monkeys. MATERIALS AND METHODS: Sixteen juvenile monkeys (Macaca mulatta) were used as experiment subjects. Animals were equally divided into 4 experimental groups based on the method of temporomandibular joint reconstruction after bilateral condylar excision via extraoral vertical ramus osteotomies. Group Condyle animals had their condylar segments immediately replaced to serve as surgical controls. Group Bone animals were reconstructed with a bony strut. Group sternoclavicular joint (SCJ) animals were reconstructed with the sternal end of their clavicles. Group costochondral junction (CCJ) animals were reconstructed with costochondral junction of ribs. Standardized lateral cephalometric radiographs with the aid of tantalum bone markers were used to evaluate mandibular growth. Twenty animals were used as controls and were allowed to grow undisturbed for an 18-month period (Group Control). RESULTS: All animals showed good mandibular function and a Class I molar relationship after an 18-month follow-up period. Statistical and graphic comparisons showed no significant difference in mandibular growth among any of the groups. CONCLUSIONS: The results of this investigation suggest that, within the limits of this model, the choice of autograft for condyle replacement may be irrelevant.

Analysis of Variance↗
PubMed1993

Mandibular condyle position: comparison of articulator mountings and magnetic resonance imaging.

This study evaluated the reliability of jaw positions, the existence of distinct jaw positions, and condyle-disk-fossa relationships in a symptom-free population by using articulator mountings and magnetic resonance imaging (MRI). The subjects examined included 28 men, 22 to 35 years of age, all having Angle Class I molar relationships and no discernible TMJ dysfunction. Records taken included the following: an axiographic face-bow to locate retruded hinge axis position, an interocclusal registration of retruded position (RE), a series of interocclusal registrations for centric occlusion (CO), a leaf gauge-generated centric relation (CR), a series of interocclusal registrations for CR, and MRI. The mandibular position indicator of the SAM articulator (Great Lakes Orthodontics, Ltd., Tonawanda, N.Y.) was used to determine reliability and existence of distinct jaw positions. Magnetic resonance imaging also evaluated jaw positions and anatomic relationships. The results indicate: (1) The articulator analysis of CO and CR is statistically replicable. (2) A distinct jaw position could be demonstrated for CO that was separate from RE and CR. It was not possible to discriminate between RE and CR. (3) Condylar concentricity was observed in half of the sample and remained consistent in RE, CO, and CR. (4) Of the sample 13% demonstrated anteriorly displaced disks that were not influenced by posterior condyle placement. (5) The clinical concept of treating to CR as a preventive measure to improve disk-to-condyle relationships was not supported by this study.

Adult↗
PubMed1983

Structure and growth activities of the mandibular condyle in monkeys (Macaca fascicularis): I. Intracondylar variations.

Eight condyles of four growing monkeys (Macaca fascicularis) of estimated ages between 1.6 and 3.6 years (minimum and maximum) were analyzed using radioautographic, histometric, and stereologic techniques. The aim of the study was to examine the relationship between intracondylar variations in structure and growth activities. The animals received 3H-proline (1 mCi/kg body weight) and 3H-thymidine (0.5 mCi/kg body weight) 24 and 3 hours, respectively, prior to sacrifice. The perichondral and chondral layers of the condylar articular covering as well as the subchondral zone of erosion were examined at different sampling sites distributed systematically in the antero-posterior and lateromedial dimension of the articulating surface. Intracondylar variations observed with respect to morphometric and radioautographic parameters suggest the following biologic mechanisms contributing to mandibular growth in a superior-posterior direction. Greater mitotic activity at the central and posterior sites of the condylar perichondrium generates a population of progenitor cells that is larger in these than in other regions. On the other hand, the rate of differentiation of these progenitor cells into chondroblasts and chondrocytes, i.e., the "migration" into and through the chondral layers of the articulating covering, seems to be enhanced in the same superior and posterior areas. Additionally, while "migrating" faster, these cartilage cells become larger and produce greater amounts of extracellular matrix than those in the anterior parts of the condyle. Finally, enhanced resorptive activities in the superior and posterior regions of the subchondral zone of erosion provide an increased "loss" of degenerated chondrocytes, thereby establishing the basis for a cartilaginous drift in the superior-posterior direction.

Analysis of Variance↗