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PubMed1992

Aberrant mandibular growth: theoretical implications.

There is a multiplicity and variety of studies investigating mandibular growth. The exact role of the mandibular condyle in influencing mandibular growth is still a point of conflict. This study was conducted with six subjects who had different condylar defects. The cranium and the skeletal profile, as well as the position of the maxilla and the mandible, were investigated. In all cases, the mandible showed a tendency toward posterior rotation. The total mandibular length was reduced with deficient corpus length and ramus height. The influence of the integrity of the condylar head and its normal articulation in the temporal fossa on mandibular growth were emphasized.

Adult↗
PubMed1987

Histologic analysis of costochondral and sternoclavicular grafts in the TMJ of the juvenile monkey.

Variability in growth response of the mandible after replacement of the mandibular condyle with the costochondral junction of a rib (CCJ) is common. Other donor graft sites that are more similar to the mandibular condyle might be more suitable for mandibular condylar replacement. Previous studies have shown the histomorphologic and developmental similarities between the sternoclavicular joint (SCJ) and temporomandibular joint (TMJ). The purpose of this study was to evaluate histologically short-term adaptations within the TMJ after replacement of the mandibular condyle with the autogenous sternal head of the clavicle, and to compare these adaptations with autogenous CCJ and mandibular condyle (surgical control) transplants. Bilateral vertical ramus osteotomies were performed in 12 juvenile Macaca mulatta with the left condyle being immediately replaced and the right condyle removed and replaced with either the sternal head of the clavicle or costochondral junction of a rib. All grafts were stabilized with maxillomandibular fixation for five weeks. Two animals in each group were killed at five, 11, and 17 weeks postsurgery and prepared for histologic analysis. The results indicate that: 1) incorporation of all grafts into the recipient site occurred and all animals had good mandibular function and occlusion throughout the follow-up period; 2) the clavicular and mandibular condylar grafts were incorporated sooner than the CCJ grafts; 3) clavicular graft changes resembled those of the condylar grafts histologically while the costal grafts remained inert and unchanged; and 4) a new condylar process with cartilage similar to that of a normal mandibular condyle regenerated in the costal graft animals from cells presumably contributed by the periosteum of the mandibular ramus and TMJ capsule.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Condyle position in the temporomandibular joint. Comparison between asymptomatic volunteers with normal disk position and patients with disk displacement.

Though the significance of condyle-fossa relationship in the temporomandibular joint has not yet been clarified and normal condyle position not yet defined, efforts have been made to guide the mandibular condyle into a centric position in the glenoid fossa with the aim of relieving the symptoms in patients with orofacial pain and temporomandibular joint internal derangement. The present study investigated the mandibular condyle position in 34 joints in asymptomatic volunteers with normal disk position as verified by arthrography and compared it with the mandibular condyle position in 85 joints in patients with different stages of internal derangement. The results showed that in the volunteers with normal joints including normal superior disk position, the condyles were almost randomly distributed in anterior, centric, and posterior positions in the glenoid fossa. Of the joints with anterior disk displacement approximately half of the number of joints with reducing disks and two thirds of the joints with nonreducing disks appeared to have posterior condyle position. Posterior condyle position cannot, however, be used to diagnose internal derangement because the condyle was found to be either in anterior or centric position in many joints with a displaced disk. The variety in condyle position in the healthy joints ought to be taken into consideration if treatment is chosen to normalize the mandibular condyle position by bringing it into a centric position in the glenoid fossa.

Adolescent↗
PubMed1991

Condylar osteochondroma manifesting as Class III skeletal dysplasia: diagnosis and surgical approach.

This is a case report of a 21-year-old man who had a gradually progressive Class III malocclusion and crepitation of the right temporomandibular joint. Routine TMJ tomograms revealed a radiopaque-radiolucent lesion of the right mandibular condyle with a compensatory anteroinferior displacement of the left mandibular condyle. Nuclear bone scans confirmed increased asymmetric technetium 99 tracer uptake in the region of the right temporomandibular joint. A two-stage surgical approach was undertaken; this consisted of excision of the condylar lesion to correct the Class III malocclusion and posterior crossbite and a LeFort I osteotomy to correct the slight transverse maxillary cant and anterior open bite. A histopathologic diagnosis confirmed osteochondroma of the mandibular condyle.

Adult↗
PubMed1997

Condylar injuries in growing patients.

Although the mandibular condyle is one of the most common sites of injury of the facial skeleton, it is also the most overlooked and least diagnosed site of trauma in the head and neck region. The condyle forms the very cornerstone of mandibular form and function and therefore injuries to the mandibular condyle in growing children may adversely affect growth and development of the jaws and the occlusion. The aim of this article is to present an overview of condylar injuries in growing patients for the purpose of increasing the awareness of all dental practitioners involved in the treatment of children with acute oro-facial injuries.

Child↗
PubMed2003

Effects of condylar fibrocartilage on the biomechanical loading of the human temporomandibular joint in a three-dimensional, nonlinear finite element model.

The present study was undertaken to test a hypothesis that the addition of articular fibrocartilage in the condyle of the temporomandibular joint reduces three-dimensional stress distribution in the condyle, the disc and articular eminence. A three-dimensional, nonlinear finite-element model was developed for analysis of joint loading before and after the addition of condylar fibrocartilage to the osseous mandibular condyle reconstructed from spiral computer topography data. In the model, each of the disc, condyle and articular eminence was arbitrarily divided into five regions: the anterior, posterior, medial, lateral and central. Von Mises stresses that in virtually all regions of the disc, condyle and articular eminence became lower after the addition of condylar fibrocartilage. Especially remarkable was the approximately four-fold reduction in von Mises stresses in the anterior, central and medial regions of the mandibular condyle. In comparison, only slight to moderate stress reductions occurred in the disc and articular eminence, suggesting that condylar fibrocartilage absorbs considerable stresses and likely dampens more loads than the disc and articular eminence. The mandibular condyle demonstrated the largest total displacement in all directions after the addition of articular fibrocartilage, followed by the disc and articular eminence. We conclude that the addition of articular fibrocartilage primarily reduces loading of the mandibular condyle, rather than the disc and articular eminence. These findings lead to a hypothesis that the mandibular condyle more likely functions as a shock absorber than the disc.

Adult↗
PubMed1999

Surgical approaches to mandibular condylar fractures: a review.

BACKGROUND AND OBJECTIVES: The estimates of mandibular condyle fracture incidence lack consensus, as these fractures are frequently overlooked or misdiagnosed, resulting in adverse effects. The purpose of this article is to review the anatomy of the mandibular condyle and the surgical approaches currently available. METHODS AND MATERIALS: Surgical treatment of mandibular condyle fractures remains controversial, due to the indications and difficulty with the associated vital structures. To aid in selecting the appropriate approach, the authors present a review of the mandibular anatomy and the approaches utilized, as reported in the literature and observed in the clinical practice of the authors. RESULTS AND/OR CONCLUSIONS: In selecting the approach, the knowledge of the mandibular anatomy is vitally important. A survey found that the preauricular, submandibular, and intraoral approaches (in that order) were preferred. When treating the fractured mandibular condyle with open reduction and internal fixation, a thorough knowledge of the anatomy of vital structures, exercise of care, and careful dissection through the soft tissues will reduce the risk for morbidity.

Carotid Artery, External↗
PubMed2006

Structural features of incremental line-like striations in mandibular condylar cartilage of c-src-deficient mice.

Mandibular condylar cartilage is sensitive to masticatory force, while mice lacking the c-src gene (c-src-deficient mice) have osteopetrosis and tooth eruption failure. The purpose of this study was to investigate the morphology of the mandibular condyle in these mice, which were maintained with a soft-food diet for 240 days after birth. The condylar head in the c-src-deficient mice showed slight deformity in shape before weaning, but showed remarkable undergrowth after weaning. No significant morphological or histological differences were detected between the mandibular condyle in wild-type mice fed soft food and those fed hard food, indicating that osteopetrosis, as well as abnormal masticatory force, influences the morphology of the mouse mandibular condyle, and that malocclusion rather than dietary consistency may have greater influence. After 70 days, incremental line-like striations consisting of cartilaginous and non-cartilaginous layers were detected in the mandibular condyle of the c-src-deficient mice, but not in the tibial growth plate. Immunostaining of aggrecan, collagen types II and X, and osteopontin was detected in the cartilaginous layers, but not in the non-cartilaginous layers showing collagen type I immunostaining. Chondrocyte lacunae were not eroded in the cartilaginous layers, and complete circumferential mineralisation around the lacunae and impaired osteoclast (chondroclast) function can account for this phenomenon. However, repeated cessation of chondrocyte differentiation may be required to completely explain the formation of the striations. These results indicate that the mandibular condyle in the c-src-deficient mice has unique structural features, adding to its deformity.

Aggrecans↗
PubMed1992

Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients.

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.

Adolescent↗
PubMed1982

Asymptomatic morphologic variations in the mandibular condyle-ramus region.

The subjects in this study exhibited considerable condylar anatomic abnormalities and discrepancies in the absence of subjective symptoms. Differences in the mandibular condyle-ramus length from one side of the mandible to the other were found. Enlargements and bony irregularities in the region of the mandibular angle were observed and appear to be associated with increased muscular activity. All these anatomic changes are visible on routine panoramic radiographs and may be predisposing factors for subjective symptoms, especially when alteration of maxillomandibular relations are made.

Adult↗
PubMed1997

Specific properties of the extracellular chondroitin sulphate proteoglycans in the mandibular condylar growth centre in pigs.

The developing condylar cartilage of the temporomandibular joint responds to changes in load by adaptive growth. Because local regulatory events taking place during growth processes are not well understood, investigation of extracellular matrix composition could provide new information about which matrix molecules are involved in the regulation of growth processes in this avascular tissue. The large chondroitin sulphate-rich proteoglycans in the mandibular condyle were compared to the proteoglycans in the weight-bearing femoral condyle of juvenile domestic pigs with respect to their buoyant density, chemical composition and immunological identity after isolation by dissociative extraction and CsCl density-gradient centrifugation. The distribution of these proteoglycans was studied in cryosections of mandibular condyle by immunohistochemistry using polyclonal antibodies produced against pig large proteoglycans. In the mandibular condyle, predominantly in the articular zone, the relative amount of proteoglycans with a low glycosaminoglycan content was greater than in femoral cartilage. The large proteoglycan immunologically related to aggrecan gave a protein core of 450 kDa after enzymatic deglycosylation and clearly possessed less keratan sulphate than in femoral aggrecan. Furthermore, the mandibular tissue contained another large proteoglycan with a protein core of 550 kDa after enzymatic deglycosylation, which was immunologically related to the fibroblast-like versican. Immunohistochemistry showed aggrecan increasing in amount inferiorly. In contrast, "versican' was exclusively found in the fibrous and differentiation layers. Aggrecan is mainly responsible for shock absorption and versican and its homologues may be involved in the control of cell proliferation and differentiation. Thus the matrix components of the mandibular condyle seem to be adapted to its special functional needs including parallel articulation and growth.

Aggrecans↗
PubMed1995

Bone matrix deposition of T1, a homologue of interleukin 1 receptors.

The mouse T1 glycoprotein is a secreted molecule of the immunoglobulin superfamily with significant homology to interleukin 1 receptors. It is expressed during bone development, and the extracellular diffusible gene product is found associated with newly formed bone but not cartilage matrix. During osteogenic differentiation of mandibular condyles of newborn mice in vitro, T1 gene expression is induced shortly after cultivation and is observed throughout the differentiation process. The temporal expression pattern of the gene is an mandibular condyles indicates that T1 expression is an early marker of osteogenic differentiation. This view is substantiated by the analysis of T1 gene regulation in continuous osteogenic cell lines. Both in differentiating osteoblast-like KM-1K cells derived from mandibular condyles and in MC3T3 cells, T1 gene activity is preferentially associated with early differentiation stages. In mandibular condyles, the secreted extracellular T1 protein is deposited into newly formed osteoid but not into cartilage matrix. This novel bone matrix protein may locally modulate the availability of its ligand.

Animals↗
PubMed1978

[Temporomandibular joint, statistical study (comparative sagittal tomography) of the relationship between the surfaces of the glenoid cavity and the condyle and condylar displacement during maximal opening].

266 sagittal tomographs corresponding to the left and right temporo-mandibular joints of 133 patients were divided into 7 groups according to the absence or presence of functional disturbances or of organic lesions. The statistical analysis of the values obtained from a "triangular study" of the surface of the glenoid fossa and of the mandibular condyle showed the following: - the average surface area of the glenoid fossa does not significantly differ from one to the other of the 7 groups examined - the average surface of the mandibular condyle did not significantly vary between groups - in no group studied, except the F/P group (function disturbances/small displacement), was there any relationship between the surface of the glenoid fossa and that of the condyle. It can, however, be stated that the relationship between the surface of the glenoid fossa and the mandibular condyle would seem to play a role in the degree of displacement of the condyle during full opening of the mouth.

Humans↗
PubMed2003

A new vascularized mandible heterotopic transplant model for studies on the growth of condylar cartilage.

PURPOSE: We developed a vascularized mandibular heterotopic transplant (VMHT) model to allow the observation of condylar cartilage growth in the absence of external and dynamic factors, such as mastication. MATERIALS AND METHODS: In VMHT, we performed a transplantation between 2 age-matched inbred rats (male Lewis rats aged 6 weeks). The hemimandibular tissue, with the common carotid artery and external jugular vein as vascular pedicle, was harvested from the donor rat and transplanted to the neck of the recipient rat with the use of vascular anastomosis under an operating microscope. To evaluate the stability of VMHT, we investigated both the weight change of the recipient rats and the blood circulatory conditions of the grafts via the radioactive microsphere method, laser Doppler blood flowmeter, and angiography. RESULTS: Although the body weight of the recipient rats decreased immediately after transplantation, these values subsequently increased, indicating a good nutritional environment in the recipient rat. Also, the VMHT graft tissue and the mandibular condyle had favorable blood circulation, equivalent to normal conditions. CONCLUSIONS: In VMHT, transplantation between the 2 age-matched inbred rats using anastomosis of the similar blood vessels enables us to minimize the influences of genetic factors, hemodynamics, hormones, and other external factors. Our investigation indicated that the transplant possessed favorable growth conditions, equivalent to the environment of the endogenous mandibular condyle. Thus, we are able to maintain conditions similar to the normal environment of the mandibular condyle. This model will be very useful in future investigations of the influences of external and functional factors on chondrogenesis and enchondral ossification of the mandibular condyle.

Animals↗
PubMed1991

Osseous and muscular changes after vertical ramus osteotomy. A magnetic resonance imaging study.

Magnetic resonance (MR) imaging was performed about 2 years after vertical ramus osteotomy of 10 patients to study changes in the mandibular condyle, cortical and cancellous bone of the proximal fragment, and muscles of mastication. MR imaging observations of the surgically treated patients were compared with findings in 10 asymptomatic untreated control subjects. The results showed that the MR appearance of bone marrow of the mandibular condyle was normal in all patients and in all control subjects. No MR evidence of avascular necrosis of the mandibular condyle was found. MR imaging artifacts from microscopic metallic particles were seen in all surgically treated regions. Thickening of the buccal and lingual cortical bone with narrowing of the bone marrow space was seen bilaterally in eight patients and unilaterally in two patients. Slight medial tipping of the mandibular condyle was seen unilaterally in two patients. Atrophic changes with decreased muscle volume and fatty replacement of muscle tissue was seen unilaterally in eight patients. None of these alterations were seen in the control subjects. MR imaging appears to be an excellent method to study morphologic changes of the muscles of mastication and osseous fragments after orthognathic surgery of the mandible. Thickening of the cortical bone and narrowing of the bone marrow space of the proximal fragment was frequently seen after vertical ramus osteotomy of the mandible and most likely represents remodeling associated with normal healing.

Adolescent↗
PubMed1990

Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients.

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.

Adolescent↗
PubMed2007

Direct AAV-mediated gene delivery to the temporomandibular joint.

Successful intra-temporomandibular joint gene transfer is a prerequisite for gene therapy to induce mandibular condylar growth. This study was carried out to investigate the expression of recombinant adeno-associated virus (rAAV) based vector-mediated enhanced green fluorescence protein (eGFP) in the mandibular condyle. The transduction efficiencies for primary chondrocytes using different hybrids of rAAV vectors were identified by fluorescence microscopy and FACS. Sprague-Dawley rats were injected with either rAAV(2/2)-eGFP construct or saline into both mandibular condyles. The spatial and temporal transgene expression was detected by in situ hybridization, RT-PCR and real-time PCR. Our result showed that rAAVs were capable of infecting rat chondrocytes. rAAV(2/2) was the best serotype to infect chondrocytes in vitro. By in situ hybridization, eGFP expression was clearly detected in the deeper layer of mandibular condyle as early as 7 days after injection. By real-time PCR, the transgene expression reached a peak at 21 days. This study was the first report to explore that rAAV-mediated genes could be transferred to mandibular condyle in vivo. Our results strongly suggest that rAAV(2/2) mediated gene delivery is a promising approach to deliver candidate genes for future regulating mandibular condylar growth.

Animals↗
PubMed2006

Chronic acidosis-induced growth retardation is mediated by proton-induced expression of Gs protein.

UNLABELLED: The etiology of skeletal growth retardation accompanying metabolic acidosis is not clear. Using ex vivo models for endochondral ossification, we showed that the cAMP/PKA pathway, probably triggered by proton sensitive G-protein-coupled receptors, is responsible for impaired skeletal growth in acidosis. INTRODUCTION: Chronic metabolic acidosis (CMA) is very often accompanied by skeletal growth retardation. We have previously shown in an ex vivo model of endochondral ossification that murine mandibular condyles subjected to acidic conditions exhibit growth retardation accompanied by a decline of insulin-like growth factor-I (IGF-I) and its receptors. PTH-induced ameliorative effects on the CMA-induced growth retardation of the mandibular condyle are partially mediated by protein kinase C (PKC). In this study we explored the mechanisms underlying the acidosis-induced growth retardation; in particular, the involvement of the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) cellular pathway in the process. MATERIALS AND METHODS: Mandibular condyles from neonatal mice or mandibular condyle derived chondrocytes (MCDCs) were incubated for 3 days under either control or acidic conditions or in the presence of cAMP-regulating factors (cAMPrf) such as forskolin, iso-butyl methyl xanthine (IBMX), or 8-Br cAMP. The effects on proliferation and differentiation of the cultures as well as on phosphorylation of cAMP responsive element binding protein (CREB) and increased expression of the alpha subunit, Gs were determined. The intracellular pH was detected using the acridine orange assay. RESULTS: Our results show that, under acidic conditions, PKA levels were increased. H89 abolished the adverse effects of acidosis on condylar development and restored IGF-I and IGF-I receptors (IGF-IR) levels. The inhibitory effects of acidosis on proliferation and differentiation of cartilaginous cells were mimicked by cAMPrf. We have also shown that acidosis stimulates activation of Gs trimeric protein and CREB phosphorylation. GDPbetaS--a Gs antagonist--abolished the acidosis-induced condylar growth arrest. Using an acridine orange assay, we showed that the intracellular environment is not acidified under acidic conditions. CONCLUSIONS: Our results indicate that the adverse effects of acidosis on skeletal growth centers are mediated at least in part by the cAMP/PKA cellular pathway. We speculate that high proton concentrations exerted by acidosis conditions stimulate proton sensitive G-protein-coupled receptors, which are mediated by the cellular cAMP/PKA pathway and induce skeletal growth retardation.

Acidosis↗