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PubMed1999

[The behaviour of rat mandibular condylar cartilage in cell culture].

This study aimed to identify the behaviour of mandibular condylar chondrocytes in vitro. Cells were harvested from the mandibular condyles of 3 week-old S. D. rats. Cell structure, morphology and characteristics were assessed by phase-contrast microscopy, scanning electron microscopy, enzymohistochemistry and immunohistochemistry. The cultured condylar chondrocytes, stellated or spindle-shaped, could grow in several layers and form many cell colonies. They could secret proteoglycans, alkaline phosphatase, type II collagen, et al. The methods of isolation, culture and identification of condylar chondrocytes were presented and discussed, which can be adopted in probing further into the cellular mechanism of functional orthopedics.

Animals↗
PubMed1992

Temporomandibular joint: surgically created disk displacement causes arthrosis in the rabbit.

To document a causal relationship between temporomandibular joint disk displacement and arthrosis, the disk was surgically displaced in one temporomandibular joint in each of three rabbits. The rabbits were sacrificed after 4 weeks and the mandibular condyles were studied radiographically and histologically. All three joints that underwent disk displacement had radiographic and histologic evidence of arthrosis, which included erosion of the bone, irregularity and fissure formation of the articular soft tissue cover, disruption of the subchondral layer of cartilage cells, and chondrocyte proliferation. No radiographic or histologic changes occurred in the joints that were untouched. The results suggest that surgically created disk displacement can cause arthrosis in the temporomandibular joint of the rabbit.

Animals↗
PubMed2005

Bone tissue engineering using polycaprolactone scaffolds fabricated via selective laser sintering.

Polycaprolactone (PCL) is a bioresorbable polymer with potential applications for bone and cartilage repair. In this work, porous PCL scaffolds were computationally designed and then fabricated via selective laser sintering (SLS), a rapid prototyping technique. The microstructure and mechanical properties of the fabricated scaffolds were assessed and compared to the designed porous architectures and computationally predicted properties. Scaffolds were then seeded with bone morphogenetic protein-7 (BMP-7) transduced fibroblasts and implanted subcutaneously to evaluate biological properties and to demonstrate tissue in-growth. The work done illustrates the ability to design and fabricate PCL scaffolds with porous architecture that have sufficient mechanical properties for bone tissue engineering applications using SLS. Compressive modulus and yield strength values ranged from 52 to 67 MPa and 2.0 to 3.2 Mpa, respectively, lying within the lower range of properties reported for human trabecular bone. Finite element analysis (FEA) results showed that mechanical properties of scaffold designs and of fabricated scaffolds can be computationally predicted. Histological evaluation and micro-computed tomography (microCT) analysis of implanted scaffolds showed that bone can be generated in vivo. Finally, to demonstrate the clinical application of this technology, we designed and fabricated a prototype mandibular condyle scaffold based on an actual pig condyle. The integration of scaffold computational design and free-form fabrication techniques presented here could prove highly useful for the construction of scaffolds that have anatomy specific exterior architecture derived from patient CT or MRI data and an interior porous architecture derived from computational design optimization.

Animals↗
PubMed1978

Glucocorticoid-induced alterations in collagen of neonatal mouse condylar cartilage.

Neonatal mice were treated with a single dose of triamcinolone hexacetonide, a long-acting synthetic analogue of cortisol, and their mandibular condyles were studied ultrastructurally ten days thereafter. A pronounced decrease in the number and size of matrix granules (proteoglycans) was found in the cartilaginous matrix of triamcinolone-treated condyles. In contrast, a marked increase concomitant with significant structural changes was noted in collagen fibrils. An obvious enhancement of collagen fibrillogenesis was noticed in the pre-mineralizing extracellular matrix. Atypical, wider than normal, banded collagen fibrils were found to form dense meshworks which appeared to lack any specific orientation or organization. It is proposed that glucocorticoid hormones, given systemically to neonatal mice, interfere with regulatory mechanisms involved with the biosynthesis of cartilaginous matrical macromolecules, i.e., proteoglycans and collagen and thereby promote certain aging processes within active growth centers.

Animals↗
PubMed2001

An appraisal of the literature on centric relation. Part III.

The literature directly and indirectly related to centric relation (CR) has been reviewed chronologically. More than 300 papers and quoted sections of books have been divided into three sections. The first two parts are related to CR. Studies in this group mainly compared, either the position of the mandibular condyle or the mandible itself in different CR recordings. Various tools were discussed for this purpose. The third part of the paper is about CR-centric occlusion (CO) discrepancy. CR still remains one of the controversial issues in prosthodontics and orthodontics. Debates such as mounting casts on the articulator by reproducible records for orthodontic treatment planning and end results, and whether or not orthodontic treatment based on CO causes TMJ dysfunction, remain unsolved. The references are listed at the end of Part III.

Centric Relation↗
PubMed1997

Radiographic findings in the teeth and jaws of 14- to 17-year-old Estonian schoolchildren in Tartu and Tallinn.

Panoramic radiographs were taken of 392 Estonian schoolchildren (33% boys and 67% girls) aged 14-17 years, 197 in Tartu and 195 in Tallinn. The mean number of permanent teeth was 31.5. In 14% of the children one to four teeth (excluding wisdom teeth) were missing. The frequencies of missing wisdom teeth and supernumerary teeth agreed with those in the literature, being 17% and 3%, respectively. The mean number of radiographically detected carious teeth was 1.9 in Tartu and 3.3 in Tallinn. Secondary caries was common, being found radiographically in half of the schoolchildren. Endodontic treatment had been given to 13% of the subjects in Tartu and to 46% in Tallinn, the success rates being 47% and 44%, respectively. The percentage of radiographic signs in the mandibular condyles of girls (5%) was greater than that of the boys (1%). Changes in the maxillary sinuses were found in 16% of the children. Eight odontogenic cysts, one cyst of the incisal canal, and one solitary bone cyst were found. Tumors included two odontomas, two cemento-ossifying lesions, and one osteoma in the maxillary sinus. The health status of the jaws of the Estonian schoolchildren was considered to be fairly good.

Adolescent↗
PubMed2000

Unilateral masticatory function changes the proteoglycan content of mandibular condylar cartilage in rabbit.

Unilateral masticatory function was induced in 10-day-old rabbits by grinding the right side molars out of occlusion under general anesthesia. The grinding procedure was repeated twice a week thereafter. They were killed at the ages of 25 and 35 days. Rabbits of the same age with uninterfered occlusions served as controls. The changes in articular cartilage of the mandibular condyle were studied biochemically and histochemically. There was a significant decrease in the proteoglycan content of the condylar cartilage in both groups of animals subjected to molar grinding compared to the animals with untouched occlusions. Especially the amount of aggregating proteoglycans was reduced. The condylar cartilage matrix synthesis is sensitive to loading produced by masticatory function during growth. The mechanical properties of the articular cartilage after a period of unilateral mastication will be impaired and it is possible that this makes the joint cartilage more susceptible to pathological events.

Adaptation, Physiological↗
PubMed1988

Temporomandibular joint arthrography without fluoroscopy.

An arthrographic technique for the temporomandibular joint that can be performed in a dental surgical room is described. This technique utilizes a dental radiographic unit and extraoral cassettes for visualization of the needle tip in the inferior synovial space for arthrography. The radiographic visualization is combined with tactile discernment of the needle tip on the mandibular condyle. The successful application of these two methods makes fluoroscopy unnecessary. After an initial success rate of 81% (34 of 42 attempts), we have used the technique successfully in more than 100 cases. Most of the problems encountered with this technique can be attributed to initial operator inexperience. This technique is not suggested as a replacement for fluoroscopy. However, it is a convenient, economical technique that can be used in the dental surgical room by trained clinicians when arthrography is indicated to determine meniscal-condylar relationships and meniscal perforations.

Arthrography↗
PubMed2002

Clinical and magnetic resonance imaging study of unilateral sideways disc displacements of the temporomandibular joint.

The aim of our study was to find symptomatic diagnostic factors for sideways displacement of the temporomandibular joint disc, compared with anterior or rotational disc displacement. A consecutive series of 2310 temporomandibular joints were examined with MRI to define the clinical signs and symptoms particularly related to sideways disc displacement compared to anterior disc displacement with logistic regression model. Bone change of the mandibular condyle and age were negatively related factors in differentiating cases with lateral disc displacement from anterior disc displacement without reduction. Range of mouth opening (over 40 mm) was a significant predictor (odds ratio 4.5865 for lateral disc displacement). This study suggested the wide opening of the mouth to become the predictor for the lateral disc displacement among the cases suspected to have disc displacement without reduction.

Adolescent↗
PubMed1991

Magnetic resonance imaging and tomographic evaluation of occlusal appliance treatment for advanced internal derangement of the temporomandibular joint.

This study evaluates the positional relationship of the disc and mandibular condyle in patients with late opening clicks treated with appliance therapy. A total of 30 joints (18 patients) were studied. Twenty-seven of these 30 joints were treated with the appliance until the joints were silent to auscultation. The patients were then evaluated with axial corrected tomography and magnetic resonance imaging (MRI) in the centric occlusion position and with their bite appliance (Sved-type) in place. Comparisons were made between condyle position in centric occlusion and with the appliance in place. Magnetic resonance imaging was then used to evaluate disc positional changes. Each imaging procedure was made in the same sagittal plane. Only changes in condyle positioning could be identified. Evidence of disc repositioning with the appliance in place was seen in only three MRI examinations. The remaining 27 joints continued to exhibit disc displacement with various changes in disc morphology. It is concluded that the concept of "disc capture" is a clinical term only, and that such perceived clinical success should not lead to the assumption that an actual change in intra-articular anatomic relationships has occurred. Joint noises may decrease because joint space is increased, allowing smoother condylar translation beyond disc surface irregularities and positional abnormalities.

Cartilage, Articular↗
PubMed1993

[Production of monoclonal antibody that recognizes glycogen and its application for immunohistochemistry].

In this study, I made a monoclonal antibody, using the mandibular condylar cartilage as antigen. By light microscopic immunocytochemical observations, this antibody reacted with the chondrocytes both in the mandibular condyle and the costal cartilage, hepatocytes and skeletal muscle cells. By electron microscopic immunocytochemical observations, reaction products (gold particles) were seen on the glycogen particles in the chondrocytes. Further, by dot blotting assay, this antibody was found to react directly with the purified glycogen. Meanwhile, all these reactions disappeared after alpha-amylase digestion. These results indicate that this antibody specifically recognizes glycogen or glycogen-related sugar chains. Therefore, I think that this antibody is very much useful for detecting the glycogen instead of the PAS reaction, since PAS reaction is not a specific method to detect the glycogen.

Animals↗
PubMed1991

Ultrastructural observation on matrix fibers in the condylar cartilage of the adult rat mandible.

In this study, ultrastructural and immunohistochemical studies were performed on the adult rat (15 weeks old) mandibular condyle, with particular attention to the matrix fibers in the condylar cartilage. The fibrous zone had thick collagen fibrils which formed fibril bundles. These collagen fibrils consisted mainly of Type I collagen. From the proliferative zone to the mature zone, the density of the collagen fibrils became higher. In the hypertrophic zone, thick collagen fibrils were formed around the chondrocytes. Immunohistochemical study indicated that these collagen fibrils consisted mainly of Type I collagen. Therefore, it was confirmed that the hypertrophic chondrocytes in this tissue had one of the osteoblastic phenotypes.

Animals↗
PubMed1989

Direct coronal high resolution computed tomography of the temporomandibular joints in patients with rheumatoid arthritis.

Direct coronal high resolution computed tomography (CT) examination of the temporomandibular joints (TMJ) was performed in 40 patients with rheumatoid arthritis (RA). The patients were divided into 3 groups. Group 1 included patients with juvenile rheumatoid arthritis (JRA). Four patients of this group had disability of the TMJ associated with overgrowth of one of the mandibular condyles. This phenomenon has not yet been reported. Group 2 consisted of 10 patients with RA with clinically asymptomatic TMJ, 4 of whom had mild erosions of the condylar head seen on CT, consistent with RA. The majority of patients in Group 3, with clinically symptomatic TMJ showed CT changes of various degrees, which are discussed in this paper. Mild bone changes, not demonstrated by conventional procedures, were clearly seen by CT. Coronal view of the CT examination had advantages over other projections.

Adolescent↗
PubMed1978

Differential craniofacial skeletal changes after postnatal experimental surgery in young and adult animals.

To find answers to the many questions about abnormal postnatal growth and change of the craniofacial skeleton, a series of surgical experiments was carried out in both young and adult animals. The purpose of this review is to relate this information to basic ideas about bone change and some local factors which may or may not affect skeletal changes. No gross regional deformity was noted after resection of sutures in young animals. The growth of bone at sutures was secondary or compensatory to other factors. In young animals, increase in size of the nasal or orbital cavities decelerated considerably after resection of either nasal septum or orbital tissues. With an increase in volume of orbital contents, orbital volume increased. These prominent gross changes in young animals were not noted in adult animals after resection of nasal septum, enucleation of the eye, or intrabulbar injection of silicone. After unilateral resection of the mandibular condyle in both young and adult monkeys, an extreme unilateral facial skeletal deformity developed. The important factor apparently was loss of integrity of the temporomandibular joint rather than loss of a growth site. The craniofacial skeleton, a three-dimensional mosaic of bones and cavities, develops as a result of the synchronous coordination of the differential activities at various sites. The dynamics of the growth and change are a fascinating, complex, incomplete chapter of biology. An understanding of factors that may or may not influence the craniofacial skeleton in both young and adult animals can aid diagnosis and surgical treatment.

Age Factors↗
PubMed2001

Atypical hemifacial microsomia associated with Chiari I malformation and syrinx: further evidence indicating that chiari I malformation is a disorder of the paraaxial mesoderm. Case report and review of the literature.

The authors present the first known reported case of hemifacial microsomia associated with a Chiari I malformation and syrinx. A 14-year-old girl presented with progressive torticollis of 3 years' duration and headaches exacerbated by exercise. Computerized tomography scanning and magnetic resonance imaging revealed extensive craniofacial and vertebral abnormalities, including aplasia of the floor of the left middle fossa and posterior fossa cranium, articulation of the left mandibular condyle with the left temporal lobe, and progressive development of a Chiari I malformation with associated syringomyelia. The patient first underwent posterior fossa decompression, duraplasty, and occipitocervical fusion. This procedure was later followed by reconstruction of the floor of the left middle fossa and temporomandibular joint. The patient's outcome was excellent. In this case report the authors review the complex embryological development of craniofacial and craniovertebral structures, and emphasize the use of a staged approach to treat pathophysiological consequences of this congenital anomaly.

Adolescent↗
PubMed2003

A study of volumetric visualization and quantitative evaluation of bone trabeculae in helical CT.

OBJECTIVES: The aim of this study was to investigate the reliability of quantitative evaluation of bone trabeculae by helical CT. METHODS: Ten specimens of human cadaver mandibular condyles were examined using both micro-CT and helical CT, and volume rendered three-dimensional (3D) images were obtained from the CT data. Micro-CT was used as the reference standard. From the micro-CT data images, bone trabeculae in each condyle were extracted by image processing and their volumes were calculated automatically. From the helical CT data images, the cortical bone was manually removed and bone trabeculae in each condyle were extracted using opacity curve and colour mapping thresholds. The optimal cut-off CT value that resulted in a similar volume of bone trabeculae obtained from helical CT and micro-CT data was investigated. RESULTS: The optimal cut-off CT value to assess the volume of bone trabeculae accurately on 3D images obtained with helical CT data was found to be 200 Hounsfield units. CONCLUSIONS: This study suggests that quantitative evaluation of bone trabeculae using helical CT might be a valid and useful method.

Aged↗
PubMed1997

Pigmented villonodular synovitis of the temporomandibular joint.

Pigmented villonodular synovitis is a proliferative disorder affecting the synovium and may be an aggressive local process with bone destruction and invasion of contiguous structures. Involvement of the temporomandibular joint is very rare. We report a rare case of pigmented villonodular synovitis of the temporomandibular joint that invaded the infratemporal fossa with bone destruction of the mandibular condyle. Magnetic resonance imaging was effective in delineating the extent of the lesion in the infratemporal fossa. Fine-needle aspiration cytology showed multinucleated giant cells and round or spindle-shaped cells with hemosiderin deposits. The tumor was resected en bloc through a combined temporocervical and infratemporal fossa approach. The postoperative histological diagnosis was a variant of pigmented villonodular synovitis. Fine-needle aspiration cytology and magnetic resonance imaging proved to be useful in the preoperative diagnosis of pigmented villonodular synovitis of the temporomandibular joint and in the preoperative planning that is required to obtain adequate surgical margins.

Biopsy, Needle↗
PubMed1977

Ultrastructure of the condylar articular surface in severe mandibular pain-dysfunction syndrome.

Specimens from articular surfaces of normal human mandibular condyles are compared with very small biopsies from articular surfaces of condyles taken at conservative operations in severe pain-dysfunction syndrome (P.D.S.). Immediate fixation was followed by examination using transmission electron-micrography. Normal surfaces exhibit a nearly structureless layer about 2 micron thick, which corresponds with the lamina splendens described in other diarthrodial joints. This layer surmounts a dense main structure of wavy interlacing bundles of collagen interspersed with fibrocytes. Occasional straight elastic fibres were found. Surfaces of all condyles from P.D.S. patients showed loss of lamina splendens, alteration of collagen fibre size, and tendency to dissociation of both collagen and its surrounding ground substance. Depper levels showed aggregations of bizarre structures which the author terms "vermiform bodies", and which appear to be collections of abnormal amounts and types of elastic tissue. It is suggested that the appearances are those of stress elastosis. Such profound ultrastructural changes may affect the joint sliding properties, and also its mechanical integrity under stress. Examination at this degree of magnification suggests a direct relationship between long-standing pain-dysfunction syndrome and the onset of degenerative disease.

Adult↗