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Osteomas are benign bone neoplasms, classified as either peripheral or central. The peripheral variant is rare, with only six cases reported involving the mandibular condyle, that are not related to Gardner syndrome. The seventh case of peripheral osteoma involving the mandibular condyle is reported in this paper.
In order to study the modifying effects of functional appliances on the mechanical environment of the temporomandibular joint (TMJ), we characterised the structure of the mandibular condyle subsequent to an experimental functional appliance intervention. Eight, four-month-old, castrated male Merino sheep, were randomly allocated to experimental and control groups (n = 4 in each group). Forward mandibular displacement was induced with an intraoral appliance. The study period was 15 weeks, during which time fluorochromes were administered to all of the animals. Midsagittal sections of the TMJ were selected for analysis and trabecular anisotropy was estimated using bone histomorphometry. Only the experimental group demonstrated that the trabecular bone in the central condylar region was less anisotropic when compared to the subchondral region. Also, the variation in trabecular anisotropy of the central condylar region was found to be smaller in the experimental group. The collagen fibre orientation was analysed under polarised light as the proportion of the dark or bright fibres observed in regions which existed before, and regions which formed during the experiment, as determined by the fluorochrome labels. In the experimental group, more bright collagen fibres were found in the most superior region of the mandibular condyle when compared with the controls. These results suggested that the experimental functional appliances changed the orientation and pattern of the mechanical forces acting on the mandibular condyle, and possibly increased the magnitude of the lateral functional forces applied to the most superior part of the condyle during such treatments.
A case of complete remodelling of bilateral fractures of the mandibular condyle in an 11-year-old boy is presented. Initial radiographic examination revealed fractures of the right and left condylar neck with medial and anterior dislocation of the proximal fragment. The fractures were treated conservatively, with a short-time intermaxillary fixation and early jaw function, and thirty-five months later the patient was asymptomatic. Radiographic changes observed following treatment have revealed a gradual return to normal shape and position of the condyles.
Pretreatment panoramic radiographs and patient files of 625 orthodontic patients (269 males and 356 females), aged 4-15.9 years (mean 11.0, SD 1.7) were evaluated with special emphasis on the mandibular condyles and malocclusions. Radiographic characteristics in the mandibular condyle were seen in 14 children (2.2 per cent), comprising six boys (2.2 per cent) and eight girls (2.3 per cent). There were no statistically significant differences between orthodontic patients before treatment and normal population controls (n = 410,229 males and 181 females, mean age 11.4 years, SD 1.8). No statistically significant difference in the frequency of condylar characteristics was found between younger (under 12) and older (over 12) children. Angle Class II molar relationship was the only type of morphological malocclusion associated (P < 0.05) with condylar characteristics. The means of several cephalometric measurements in the children with condylar characteristics were close to those of children with harmonious skeletal relationships.
PURPOSE: To study the tissue layers and their function of the cartilage in mandibular condyle in rabbits. METHODS: Six adult Japanese white rabbits were subjected. Their temporomandibular joints were studied by immunohistochemistry for FGFR3 and PCNA, and in situ hybridization for aggrecan and collagen II mRNA expression, as well as ultrastructure. RESULTS: The upper proliferative cells did not express FGFR3, but the lower proliferative cells expressed FGFR3. Only few cells in the upper proliferative layer were PCNA positive, but all cells in the lower proliferative layer were positive for PCNA. No collagen II mRNA expression was found in the upper proliferative cell, but aggrecan and collagen II mRNA coexpressed in the lower proliferative layer. The cells in both layers were different in ultrastructure. CONCLUSION: The cartilage in mandibular condyle should have the 5 following tissue layer: fibrous layer, proliferative layer, transitional layer, cartilaginous layer and calcified cartilaginous layer. The cells in the proliferative layer are undifferentiated and the cells in the differentiated layer are prechondrocytes.
We have established two clonal cell lines, designated SM1/9 and SM25/3 from the mandibular condyles of newborn BALB/c mice by immortalization with the SV40 large T antigen. These cells have a high proliferative activity and have been maintained in culture for over 50 passages. They are polygonal in shape. Electron microscopic studies indicate an immature phenotype for both clones and a lack of prominent intracellular filaments typical of fibroblasts. SM25/3 demonstrates different biological properties as compared to SM1/9, it is tumourigenic in nude mice, has a faster growth rate and exhibits less differentiated features. Both cell lines have low constitutive levels of alkaline phosphatase, and the activity of this enzyme is increased significantly in a dose and confluency dependent manner by retinoic acid and 1,25 (OH)2 vitamin D3. The cells express transcripts for retinoic acid receptors mRAR-alpha and mRAR-gamma but not for mRAR-beta. They also express mRNA for the 1,25 (OH)2 vitamin D3 receptor. They co-express transcripts for collagen types I, II, III. Expression of mRNA for extracellular matrix proteins such as biglycan, osteopontin, PAI-1 is detected. Cultured cells do not express mRNA for osteocalcin and this transcript is not inducible with 1,25 (OH)2 vitamin D3 or retinoic acid. Chondrocyte markers such as link protein and aggrecan are not detected. In vitro assays indicate that the cell lines have a limited capacity for osteogenic or chondrogenic differentiation. Similarly agarose culture experiments and extended treatment with retinoic acid indicate that they do not resemble dedifferentiated chondrocytes. Both the cell lines appear to express a phenotype intermediate to osteoblasts and chondroblasts and possibly represent transitional differentiation stages of the progenitor cells of the mandibular condyle. These cells could serve as useful models in elucidating the pathways of early mesenchymal cell differentiation.
Skeletal growth during the early postnatal period is thought to be GH-independent, and is probably regulated by intrinsic growth factors. We studied the involvement of locally produced insulin like growth factor-I (IGF-I) in the growth of the neonatal mandibular condyle. Immunofluorescence studies revealed intense staining with antibodies to IGF-I in the mandibular condyle of 2-day-old ICR mice. We have also shown that these mandibular condyles contain specific high-affinity binding sites (Kd = 0.157 nmol/l) for IGF-I (427 fmol/mg). Autoradiographical studies of iodinated IGF-I revealed that the distribution of the receptors for IGF-I was parallel to that of IGF-I production, mainly in the younger zones of the condyle, namely the chondroprogenitor and the chondroblast cell layers. Immunoinhibition of IGF-I resulted in an almost complete inhibition (-91%) of thymidine incorporation into DNA, as well as in marked degenerative changes in the morphological appearance of the condyle. Our studies support the hypothesis that early postnatal growth is dependent on the paracrine activity of endogenous GH-independent IGF-I.
Two cases of peripheral osteoma of the mandibular condyle are described. This lesions is uncommon. It is suggested that peripheral osteoma of the mandible may be traumatically induced and that muscle traction plays an important role in this lesion.
This study investigated the differences of age distribution and temporomandibular joint (TMJ) pain between marrow edema and osteonecrosis in the mandibular condyle. Subjects consisted of 35 TMJs in 35 patients with abnormal bone marrow on MR images who were selected from a consecutive series of 527 patients with TMJ disorders. Proton density and T2-weighted MR images taken in the oblique sagittal and coronal planes were used to diagnose condylar marrow abnormalities and divide them into either edema or osteonecrosis. The differences in TMJ pain and age distribution for these two abnormalities were assessed with the one-sided Wilcoxon rank sum test with 0.05 alpha level. The degree of pain was higher in joints with marrow edema than in joints with osteonecrosis (p = 0.033). The mean age was higher in joints with osteonecrosis (p < 0.001). Our results suggest that there is more severe pain in TMJs with marrow edema of the mandibular condyle than in those with osteonecrosis. Since the patients with marrow edema have lower age, it also appears that marrow edema may be a precursor condition for osteonecrosis of the TMJ.
A case of osteochondroma of the right mandibular condyle in a 47-year-old woman is presented. Instead of condylectomy, surgical resection was performed, resulting in fewer functional changes and less dysfunction of the temporomandibular joint but recurrence within 12 months after surgery.
A case is presented of a massive osteochondroma of the mandibular condyle leading to marked facial asymmetry, painful mastication, disturbed occlusion and impaired hearing on the affected side. The diagnosis was confirmed by radiological and histological examination. A tentative treatment plan including surgery on both jaws was proposed but had to be modified because of the patient's reluctance to undergo any surgery on the maxilla.
The morbidity following conservative management of fracture dislocations of the mandibular condyle is considered, and the theoretical advantages of open reduction discussed. The various methods described in the past are reviewed and a new technique is described whereby a Kirschner wire is drilled into the condylar fragment and then inlaid into the ramus. Advantages over previous methods include easy manipulation of the fragment and lack of danger to the facial nerve.
In order to analyse the regional and age-related variations of primate condyles, immunohistochemical techniques were used to examine the localization of types I, II and III collagen and a variety of glycosaminoglycans in distinct anteroposterior regions of the mandibular condyle of two growing female rhesus monkeys (Macaca mulatta). In the juvenile monkey staining for types I and III collagen was weak in the fibrous tissue layer, intense in the pre-cartilaginous tissue layer and faint in the cartilaginous tissue layer; staining was significantly more intense in the posterosuperior and posterior regions than in the anterior region. Similarly, staining for cartilage-characteristic extracellular matrices, including type II collagen and keratan sulfate, was intense in the cartilaginous tissue layer of the posterior condyle. In contrast, in the late-adolescent monkey staining for the extracellular matrices was more intense in the anterior half of the condyle (i.e. from the anterior to the posterosuperior region) than in the posterior region, and most intense in the posterosuperior region. The results demonstrate that marked regional differences exist in the phenotypic expression of the extracellular matrices in the mandibular condyles of growing monkeys and that these differences vary between different developmental stages. The variations probably reflect the predominance of competing growth and articulatory functions in the mandibular condyles.
Condylar positioning problems have been associated with temporomandibular joint signs and symptoms. The position of the mandibular condyle is difficult to predict and quantify with existing routinely used radiographic techniques. An investigation was implemented to test the validity and reliability of digital subtraction to enhance transcranial plain films and to quantify positional changes of the condyle in a laboratory model. The model consisted of a mounted dried human skull and a mandibular condyle attached to a micromanipulator. Controlled changes in condylar position were made, and the condyle and fossa were imaged. The data were analyzed with descriptive statistics, analyses of variance to evaluate the sources of variability, and linear contrasts to evaluate the differences between observed and expected values. The results indicated that digital subtraction detected posterior positional change within 10% of the expected value. However, inferior positional changes were poorly detected and lateral positional changes could not be evaluated by this technique. We conclude that digitally subtracted transcranial radiographs may be useful for detection of posterior condylar movements, assuming that appropriate head-holding devices are used to fix x-ray source and head geometry.
STATEMENT OF PROBLEM: It is important for dentists to understand the effect of systemic hormonal change on the osseous oral structures. PURPOSE: This study examined the effect of aging and ovariectomy on rat mandibular condyle. MATERIAL AND METHODS: Seventy-two 120-day-old female Fischer rats were killed at 7, 14, 30, and 60 days after bilateral ovariectomy or sham surgery. As the baseline control group, eight animals were killed on day 0 without surgeries. Changes in the bone mineral density and bone marrow area were detected through dual-energy x-ray absorptiometry and soft x-ray photography, respectively. RESULTS: No significant difference of bone mineral density was found between the bilateral ovariectomy and sham surgery groups with dual-energy x-ray absorptiometry, probably because the thickness of cortical bone obscured any possible changes in trabecular bone. Age-related osteosclerotic changes were found in the sham group with soft x-ray photography. In contrast, the bilateral ovariectomy group showed little change in bone marrow area in relation to time course; on the other hand, the value of their bone marrow area became significantly larger than that of the sham surgery group from 14 days after ovariectomy onward. CONCLUSIONS: It was inferred that estrogen deficiency caused the significantly large marrow area found in the rat mandibular condyle. Although much more research is necessary, this study allowed us to speculate that osteoporotic changes may occur in the mandibular condyle of postmenopausal women.
PURPOSE: This study determined the osteoarthrotic changes in the human mandibular condyle in relation to aging and the loss of dental occlusal contacts. MATERIALS AND METHODS: Thirty-four condyles obtained at autopsy were studied morphologically, radiologically, and histologically. RESULTS: With advancing age, the articular surface of the mandibular condyle morphologically showed severe degenerative changes. The condyles with these changes tended to be from the side of the mandible with minimal areas of occlusal contact. Radiographically, an irregularity of the cortical bone plate was most commonly seen in the fifth and sixth decades, whereas a polygonal or flattened structure was mainly observed after the seventh decade. CONCLUSION: The histologic findings suggest that a decrease in the cellular components with advancing age may play a critical role in the development of degenerative changes.
OBJECTIVES: The purpose of this investigation was to evaluate the biomechanical behavior of various rigid internal fixation techniques for mandibular condylar process fractures. MATERIALS AND METHODS: Synthetic mandible replicas (Synbone, Landquart, Switzerland) were used to evaluate a control, and four monocortical mandibular condyle plating techniques. Each group was subjected to linear loading in lateral to medial, medial to lateral and posterior to anterior directions by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. Yield load, yield displacement, and stiffness were measured. In addition, each group was subjected to torsional loading using an Instron 8521 (Instron). Yield torque, yield rotation, and stiffness were measured. Five samples were tested for each group and method of loading (n = 100). Means and standard deviations were derived and compared for statistical significance using a 1-way analysis variance (P <.05). Third-order polynomial best-fit curves were also created for each group to further evaluate and compare the mechanical behavior. RESULTS: Statistically significant differences were noted between fixation groups for the different mechanical measures evaluated under the different conditions of linear loading. Statistically significant differences were noted between groups for yield rotation during torsional loading. Although different in magnitude, similar patterns of mechanical behavior were observed in the third-order polynomial best-fit curves for lateral to medial loading, medial to lateral loading and torsional loading. For posterior to anterior loading, different patterns of mechanical behavior were noted between the experimental groups, but similar behavior was noted between the control and mini dynamic compression plate CONCLUSIONS: While differences were noted between each of the fixation systems in their abilities to resist loads under the conditions tested, the mini dynamic compression plate provided the most favorable mechanical behavior. Based on the presumed clinical parameters, we can suggest that none of the systems evaluated were ideal for the treatment of mandibular condyle fractures, but that the mini dynamic compression plate is the closest to an effective means for reconstruction.
One case of giant cell tumor located in the mandibular condyle is reported. This case was revealed by a progressive mandibular deviation. Frequency, localization, etiopathogenesis and histological feature are discussed.