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PubMed1988

Mechanism of adaptation in the mandibular condyle of the mouse. An organ culture study.

The cranial base and whole mandible of 7-day-old mice were cultured for 1 or 2 weeks in a novel organ culture system that provided an articulating movement for the temporomandibular joints. The mandibles were articulating either in a closed or in an open position to simulate the in vivo mouth-breathing pattern. The reactions of the condylar processes were followed macroscopically and microscopically after osteoid or von Kossa staining. After 1 week of culture, small differences were found in the shape of the condylar processes between the two groups. After 2 weeks, significantly increased growth was observed superiorly in those condyles which had been working in a closed position and posteriorly in the condyles which had been working in an open position. Histologic analysis revealed that after 1 week calcification had proceeded faster in the posterior aspect of the condyles in the mandibles which had been working in a closed position as compared to the mandibles which had been working in an open position, and the difference was even more marked after 2 weeks. In the latter condyles calcification had proceeded markedly in the anterosuperior aspect. Osteoid staining showed that perichondrial mesenchymal cells had differentiated into osteoblasts in the posterior aspect of the condyles in those mandibles which had been working in a closed position. This led to a ceasing of expansive growth in the posterior aspect and thus to a more upwardly directed condylar growth. In mandibles which had been working in the open position to simulate the mouth-breathing pattern in vivo, chondrogenesis and thus expansive growth continued in the posterior aspect, leading to a more posteriorly directed condylar growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Distribution and histologic character of osseous concavities in mandibular condyles of young adults.

Osseous concavities at the bone--articular soft-tissue interface were identified in 23% of 53 young adult TMJ condyles, with most occurring in the superior sector of the lateral and central aspects. All were filled with articular soft tissue, which provided a smooth articular surface without any evidence of surface breakdown. By extrapolation, radiographic evidence of osseous concavities in this age group should not be interpreted as evidence of articular surface breakdown (arthrosis). The long-term outcome of these concavities cannot be determined from this histologic cross-sectional study. However, the results support initial conservative therapy with monitoring over time.

Adolescent↗

PubMed1992

Ultrastructural alteration of cartilaginous fibril arrangement in the rat mandibular condyle as revealed by high-resolution scanning electron microscopy.

Three-dimensional alteration of fibrillar matrix in the rat mandibular condylar cartilage was investigated with a high-resolution scanning electron microscope (SEM) and it was determined whether alterations correlate with developing occlusion and advancing age. Two important SEM techniques of DMSO freeze-cracking and treatment with trypsin and hyaluronidase were employed to remove interfibrillar proteoglycans and disclose fibril arrangement. Our SEM investigation demonstrated that collagen fibrils in the fibrous zone covering hyaline-cartilaginous area in the condyle are thicker (50 to 80 nm in diameter) than the fibrils (30 to 50 nm in diameter) that predominantly constituted an interterritorial fibrillar matrix (IFM) in the area. While the thick fibrils had a distinct striation of about 55 nm periodicity, the thin fibrils had no distinguishable striation. The thick fibrils having a periodic striation of about 60 nm was found along with the thin fibrils, also in the IFM in the aged rats and in the deep IFM, but were considerably less than the thin fibrils. The fibrils in the fibrous zone and IFM were disorderly arranged at 19-day-insemination age. In 1-week-old rats whose incisors erupted, the fibrils constituting the fibrous zone altered from disordered to ordered arrangement. The IFM in these rats took the form of a network. Incorporation of small fibrillar bundles into the fibrillar network was seen in 2-week-old rats whose upper and lower first molars erupted. In 8-week-old rats whose molars had erupted completely, the IFM completely occupied by regularly oriented fibrils appeared additionally.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

[The mandibular condyle. The prenatal evolutionary process].

Fourteen prenatal maxillary condyles were studied from 66 to 305 mm. vertex-coxa, making slides with different orientation and using several staining techniques. The most significative characteristics were described in the different ages. The lining connective tissue increased its thickness but not change appreciably its structure. The mesenchymal layer, generating cells, maintained its character, but its columnar invaginations observed early were getting more tense as its age increased. The cartilage without typical isogeneic groups and few intercellular substance, decreased as substituted by osteoid trabeculae observing few osteoclasts. In the subchondral area, the difference between the columnar mesenchyma and haematogenous narrow was outstanding.

Gestational Age↗

PubMed1989

Mandibular condyle morphology in relation to malocclusions in children.

Recent studies show that forces applied to the mandible during treatment with functional appliances and other orthodontic therapies produce changes in the TMJ. Specific malocclusions might also apply forces that can produce changes in the morphology of the TMJ. This study examined 104 orthodontic patients (44 males and 60 females) prior to treatment. The size and location of the condyle was determined on submento-vertex and tomographic films which was related to clinical findings including age, sex, malocclusion type, facial type, TMJ symptoms, tooth eruption sequence, crossbites and midline discrepancies. The medio-lateral width of the condylar head correlated positively with the patients age (p less than 0.001) and sex (p less than 0.001). Also the antero-posterior widths of the condyle were correlated with age (p less than 0.05). The condylar size in males was found to be greater than in females. Midline discrepancy significantly altered the increase in condylar size during growth. Transversel anomalies had a markedly greater influence on condylar growth compared to other characteristics of occlusion. The major change in condylar size during growth occurred in medio-lateral dimension as compared to the antero-posterior. In addition, the medio-lateral width was affected by midline discrepancy but not the antero-posterior width.

Adolescent↗

PubMed1990

An immunohistochemical study of the distribution of matrical proteins in the mandibular condyle of neonatal mice. II. Non-collagenous proteins.

This study has illustrated the localisation of several non-collagenous proteins in the extracellular matrix of neonatal condylar cartilage (chondrocalcin, proteoglycans and a 100 kDa protein). Also, it has been shown that chondrocytes synthesise laminin and anchorin CII. The bone trabeculae in the primary spongiosa reacted positively for chondrocalcin, osteopontin and BMP. The cartilaginous wealth of collagens (Type I, II, VI, IX, X and XI), together with the various non-collagenous proteins, are considered to possess an important role in the maintenance of chondrogenic expression as well as in the regulation of cartilage differentiation by means of an interaction with the undifferentiated precursor cells.

Animals↗

PubMed1987

Further characterisation of the extracellular matrix in the mandibular condyle in neonatal mice.

This study provides newer information concerning the extracellular matrix of neonatal condylar cartilage--a genuine representative of a secondary type of cartilage. In addition, the data presented hereby indicate that the condylar cartilage contains a population of progenitor cells that synthesise Type I collagen rather than Type II. Under normal conditions in vivo local biomechanical factors influence the progenitor cells to differentiate into cartilage cells and thereby to shift their synthetic pathway from Type I collagen to Type II collagen--the typical collagen of cartilage extracellular matrix. In the absence of such biomechanical effects the condylar progenitor cells seem to proceed with their inherent differentiation pathway and express an osteogenic phenotype (Fig. 21).

Animals↗

PubMed1992

Mitotic activity of cells in the fibrous zone of the rat mandibular condyle.

To investigate cell renewal in this fibrous zone, Wistar rats at 3 and 6 weeks of age were injected intraperitoneally with colchicine (1 mg/kg) three times, at 10:00, 13:00 and 16:00 h, and mitotic cells were examined after killing the rats at 18:00 h. Colchicine induced a significant increase in the number of arrested metaphases in the fibrous and the proliferating cell zone. The mitotic rates (per 1000 cells per h) in the fibrous zone at 3 weeks of age were 0.426 for the superficial layer and 0.266 for the deeper layer. These findings suggest that the fibrous zone of young rats grew with the proliferation of the cells within this zone. Age-associated histological changes in the fibrous zone were related to changes in mitotic rates within that zone.

Aging↗

PubMed1998

An evaluation of digital subtraction radiography for assessment of changes in position of the mandibular condyle.

OBJECTIVE: To compare conventional visual evaluation with digital subtraction for assessing changes in condylar position on TMJ radiographs. METHODS: Horizontally corrected oblique lateral transcranial radiographs of the TMJ were taken bilaterally with and without a stabilisation or a control appliance on the same occasion in 20 patients. All of the radiographs were assessed both conventionally and following digital subtraction by seven observers. Three observers assessed both sets of radiographs twice to calculate observer agreement. RESULTS: There were no statistically significant differences in observer performance or diagnostic outcome between the two techniques. Intra-observer agreement varied between 85 and 90% for the conventional visual evaluation and between 62 and 85% for digital subtraction. Although interobserver agreement was greater with the conventional evaluation the difference was not significant. CONCLUSION: Conventional visual evaluation is recommended for the assessment changes in condylar position from TMJ radiographs.

Adolescent↗

PubMedDate not supplied

Radiographic study of changes in the mandibular condyle after implant prosthodontic rehabilitation.

PURPOSE: The aim of this follow-up investigation was to assess the influence of clinical variables after implant prosthodontic rehabilitation in patients without temporomandibular disorders on alterations of condylar morphology as seen radiographically. MATERIALS AND METHODS: In 167 patients, the condylar findings of flattening, erosion, osteophytes, and sclerosis were scored according to severity on rotational panoramic radiographs. Findings were followed up on images taken before and on average 5 years after implant prosthodontic rehabilitation. Changes were analyzed in relation to age, gender, initial radiologic status, and occlusal support pre- and posttreatment, according to Eichner groups, by logistic regression analysis. RESULTS: The majority of patients did not show structural alterations over the follow-up period, regardless of whether the condyle was already affected at the outset of the investigation. Condyles unaffected at the time of the first radiograph made up the majority of increases in radiographic score. Flattening and sclerosis were cumulative, whereas erosions and osteophytes had a more transient character. There was no influence of the mentioned clinical or radiographic findings on the development of changes. CONCLUSION: Over the investigated period, the incidence of all four noted findings doubled. However, the statistical methods employed could not detect any influence of patient variables or the insertion of implant-retained prosthodontics on the development of condylar changes in this specific patient group. Both assertions reflect the complexity of the topic.

Adult↗

PubMed1987

Growth direction in the mandibular condyle of pre-pubertal and pubertal monkeys (Macaca fascicularis) studied by morphometry and radioautography.

Eight male monkeys with prepubertal or pubertal skeletal maturity were used to assess age-related changes in anterior-posterior gradients of parameters which characterize growth velocity. The animals received single intravenous doses of 1 mCi/kg body weight of [3H]-proline at 24 h, and of 0.5 mCi/kg body weight [3H]-thymidine, 3 h before death. Four perichondral and chondral layers, and the subchondral zone of erosion of each condyle, were analysed morphometrically and radioautographically at 12 sampling sites distributed systematically over the joint surface. Values for cell density, cell proliferation, extracellular cartilaginous matrix production, cartilage resorption and subchondral bone formation produced characteristic curves which generally peaked in the central joint region. These peaks did not shift, either in relation to age or growth velocity, suggesting a uniform posterior-superior growth direction. Individual variability in both shape and prominence of the curves usually prevailed over the group effects attributable to skeletal maturity or growth velocity. Thus the gradual age-dependent shift in human condylar growth direction may be revealed only in longitudinal studies and would be masked by pronounced individual variation in cross-sectional studies of small samples.

Animals↗

PubMed1997

Reconstruction of the mandibular condyle using transport distraction osteogenesis.

Transport distraction osteogenesis was used to reconstruct the articulation of the temporomandibular joint in two patients. Patient 1 underwent a gap arthroplasty for release of a bony ankylosis. Patient 2 had degenerative joint disease after tumor resection. Both patients had painful, limited mouth opening and facial asymmetry as a result of condylar shortening. A reverse-L osteotomy was performed from the sigmoid notch to the posterior border of the mandible. An external transport distraction device was applied, and the segment was advanced superiorly, 1.0 mm per day, until contact was made with the glenoid fossa. After distraction, the bone was found to have remodeled, inducing a new cortical layer on the articular surface. Additionally, a pseudodisk was generated as a result of the transport distraction. The two patients tolerated the procedure well, returning to pain-free normal mouth opening and being able to masticate regular diets.

Adult↗

PubMed1996

[Mandibular condyle hyperplasia. Therapeutic review].

Excessive cartilage growth on the condyle process of the mandible can result from primary hyperreactivity of the growth cartilage or be a secondary adaptation to an imbalance in occlusive and/or cervicofacial conditions. Treatment depends on the distinction between these two forms. Primary active overgrowth is treated by condylectomy sparing the distal apparatus although conservative surgery to re-centering the temporomandibular joint and re-establish symmetry without condylectomy may be used in quiescent moderately active forms saving the joint. For secondary forms, the joint is re-centering and symmetry is re-established without condylectomy. If started early enough, orthopaedic treatment can avoid the development of secondary forms resulting an imbalance in occlusive and/or cervicofacial conditions.

Diagnosis, Differential↗

PubMed1993

Mandibular condyle lesions related to age at onset and subtypes of juvenile rheumatoid arthritis in 15-year-old children.

The severity of lesions in the temporomandibular joint (TMJ) area and their association with age at onset, the various forms of juvenile rheumatoid arthritis (JRA), and certain serologic tests for rheumatoid factor (RF), antinuclear antibodies (ANA), and human leukocyte antigen (HLA)-B27 were determined in 15-yr-old children. The series comprised 121 JRA children, 78 girls and 43 boys, in whom an analysis had recently been made of the relation of TMJ lesions to jaw movement and occlusal status. The mean age at onset was 7.3 yr, the girls contracting JRA earlier than the boys. Also, the girls with lesions in the TMJ area were significantly younger than those with no lesions. TMJ abnormalities were found in 50% of cases with a pauciarticular or systemic onset, but in 72% of those representing the polyarticular subtype. Flattened condyles and grave lesions were equally represented in all subgroups and in both sexes. A crossover from onset type to present diagnosis was found in 30% of the cases, mostly from pauciarticular to polyarthritis, which also increased the risk of TMJ lesions from 50 to 60%. RF, ANA, or HLA-B27 alone did not seem to be associated with a risk of TMJ abnormalities. Maximal opening capacity is more restricted in patients with early onset or a polyarticular mode of JRA. Since the TMJ is affected in more than half of JRA children, regular measurements of maximal movements of the mandible or roentgenologic examinations of the TMJ are essential for their optimal treatment.

Adolescent↗

PubMed1997

Movements of the mandibular condyle kinematic center during jaw opening and closing.

Little is known about the detailed kinematics of the human temporomandibular condyle during jaw opening and closing. According to the rotate and swing model by Osborn (1989), the condyle is kept in close contact with the articular eminence during opening. Whether the condyle is in closer contact with the articular eminence during opening than during closing is unknown. Another consequence of the model is that the opening condylar movements are less variable than the closing movements. In this study, the hypothesis that the opening condylar path is closer to the articular eminence and also less variable than the closing condylar path is tested. Twenty subjects (10 males and 10 females with a mean age of 22) without signs or symptoms of a craniomandibular disorder performed 2 series of 4 protrusive movements and 2 series of 4 empty opening-closing movements. The movements were recorded by a six-degrees-of-freedom opto-electronic jaw movement recording system (OKAS-3D). The kinematic center of the condyle was used as a reference point for the reconstruction of condylar movement paths. Characteristics of the opening and closing paths were investigated by means of a displacement index (DI). This index is the quotient between the three-dimensional path length and the three-dimensional path distance between the start and the end point of an opening or closing movement of the kinematic center. The DI was smaller (p < 0.0001) and also less variable (p < 0.0001) during opening than during closing. The smaller DI value, in combination with the concave nature of the movement path, indicates that the opening path of the kinematic center lies above the closing path and thus closer to the articular eminence.

Adolescent↗

PubMed1990

An immunohistochemical study of the distribution of matrical proteins in the mandibular condyle of neonatal mice. I. Collagens.

This study provides new information concerning the distribution of cartilage collagens in neonatal mammalian condylar cartilage. It became apparent that young cartilage cells contain pro-Type I collagen as well as pro-Type II collagen. The mature molecule of Type I collagen appears only in the extracellular matrix of the mineralisation zone close to the ossification front. Type II collagen, on the other hand, is apparent throughout the extracellular matrix as soon as the chondroprogenitor cells have differentiated into chondroblasts. In addition, Type II collagen is noticed in the core of the newly formed bone trabeculae within the primary spongiosa. Type IX collagen was found to be co-distributed with Type II collagen in cartilage and bone. Hypertrophic chondrocytes within the mineralisation zone, but in no other zone, demonstrate an intense reactivity for Type X collagen. Mild reactivity throughout the condylar process is encountered with regard to Type VI collagen. Perichondrium but not cartilage reacts positively for Type III collagen.

Animals↗

PubMed1993

Insulin enhances the growth of cartilage in organ and tissue cultures of mouse neonatal mandibular condyle.

Condylar cartilages were cultured in the form of organ cultures on top of collagen sponges in medium containing 2% fetal calf serum and were treated with 3.5-350 nM insulin for 6 days. Doses of 175 nM of insulin caused a marked increase (+96%) in DNA synthesis and in proteoglycan production (+74%), features that manifested themselves structurally by a 60% increase in overall size of the cultured explants. Using a tissue culture system comprised of cartilage progenitor cells, insulin was found to enhance the differentiation of the progenitor cells so that by 6 days in culture an appreciable nodule of differentiated chondrocytes developed. The latter was surrounded by perichondrial cells whereas the extracellular matrix within the newly formed, insulin-induced, nodule reacted positively for cartilage-specific antigens (type II collagen and bone sialoprotein). It is suggested that insulin induces a direct stimulatory effect on progenitor cell proliferation, cartilage differentiation, and extracellular matrix deposition.

Animals↗

PubMed1981

Retardative effects of a corticosteroid hormone upon chondrocyte growth in the mandibular condyle of neonatal mice.

This study examined the influence of triamcinolone hexacetonide, a long-acting synthetic analog of cortisol on the proliferative activity and subsequent development of chondroprogenitor cells in condylar cartilage of neonatal mice. It became evident that a single injection of relatively low doses of the hormone significantly reduced the uptake and incorporation of [3H]thymidine followed by a significant decrease in the number of young cartilage cells. A unique feature was the fact that at the same time condyles of triamcinolone-treated mice revealed an increase in the number of mesenchyme-like cells within the condylar chondroprogenitor zone. High values of correlation were noted between the inhibitory effects of the hormone upon the incorporation of [3H]thymidine, the number of mitotic figures (within the chondroprogenitor zone), and the dimension of the chondroblastic zone. This study indicates that in young animals fluorinated corticosteroid hormones possess a significant bivalent inhibitory effect upon both the proliferative activity of chondroprogenitor cells as well as upon capacity of the latter cells to differentiate into chondroblasts. In so doing, corticosteroids adversely affect the normal process of endochondral bone formation in one of the prominent growth centers within the craniofacial skeleton. Thus, in the developing animal, corticosteroids impair the growing mandible from expressing its inherent morphogenetic pattern.

Adrenal Cortex Hormones↗