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PubMed2000

[Quantitative 3D measurements of the skull base by using spiral volumatric CT images].

OBJECTIVE: To study the spatial relationships of mandibular condyle and carotid canal, jugular fossa, foramen ovale, foramen spinosum when mandible in normal physical position. METHODS: 100 native adults were examined by spiral volumatric CT. The data were transferred to workstation, three-dimensional(3d) cranial base images were reconstructed, 3D measurements were performed by using specific 3d CT landmarks. 12 points were defined and 28 distances and angles were measured in the skull base from submandibular viewpoint. The internal pole of condyle and the condylar long axis were regarded as the center point and 0 degree axis in the reference frame. RESULTS: Submandibular approach provided a clear vision of the internal pole of condyle and condylar long axis. The ECC was located at 12.01 +/- 2.71 mm, 5.14 +/- 1.22 degrees, Jug was located at 15.11 +/- 2.72 mm, -56.27 +/- 14.05 degrees according to the reference frame. CONCLUSIONS: Quantitative measurements of 3D skull base can be very precise. Mandibular approach is easy to show the mandibular condyle. The reference frame is helpful to located other important structures of skull base in operation.

Female↗
PubMed1991

Isolation of a cathepsin B-encoding cDNA from murine osteogenic cells.

Cathepsin B-encoding cDNA (CTSB) clones have been isolated from a lambda gt10 library of a murine osteosarcoma by differential screening during a search for genes which are typically expressed during osteogenic differentiation in mouse mandibular condyles in vitro. Sequencing of the CTSB 3' end revealed that the isolated sequence contained an 825-bp 3'-noncoding region, the polyadenylation signal and the poly(A) tail. The enhanced CTSB expression during the early stages of the enchondral ossification-like process in mandibular condyles in vitro suggests that CTSB participates in the degradation of cartilage matrix prior to the synthesis of bone matrix proteins.

Animals↗
PubMed1989

A histochemical localization on Maclura pomifera lectin during osteogenesis.

Mandibular condyles of 4-week-old Wistar strain rats and mandibles of ICR strain mice from 14 days gestation stage to 2 days postnatal stage were used to investigate the localization of Maclura pomifera lectin (MPA) during two modes of osteogenesis. During endochondral ossification of the mandibular condyle, MPA was only localized at the peripheral regions of calcified cartilage after the destruction of chondrocyte lacunae. Bone extracellular matrix (ECM) was not reacted with MPA. In intramembranous ossification of mice mandibles, MPA was stained intensively in the early bone ECM. The intensity of the MPA reaction decreased during bone development. In both cases of osteogenesis, chondroclasts and osteoclasts showed the strong affinity to MPA. These results indicated that the time- and position-specific changes within ECM proceeded during osteogenesis and that MPA was the useful probe to detect chondroclasts and osteoclasts.

Animals↗
PubMed1977

Condylar fractures of the mandible. I. Classification and relation to age, occlusion, and concomitant injuries of teeth and teeth-supporting structures, and fractures of the mandibular body.

In 123 individuals, 138 fractures of the mandibular condyle were classified with respect to fracture level, dislocation at the fracture level, and condylar head relation to the articular fossa. The age of the patient and the location of the most distal occlusal contact were recorded as well as teeth injuries and concomitant fractures of the mandibular body. The position of the most distal occlusal contact did not influence the dislocation of the condylar fragment. Teeth injuries such as fractures and luxation were found to be associated with condylar head or neck fractures, whereas the concomitant fractures of the mandibular body were mostly seen with the subcondylar fractures. Teeth injuries as well as concomitant fractures of the mandibular body were found more frequently in patients with bilateral than unilateral condylar fractures. Fractures of teeth in the molar and bicuspid regions were most frequent on the condylar fracture side, while the concomitant fractures of the mandibular body were located to the contralateral side. Medial angulation of the condylar fragment with lateral override at the fracture level was the typical fracture in adults, and angulation without override the characteristic fracture in growing individuals. Medical override occurred both in children and in adults and seemed to be the result of more severe trauma to the chin.

Accidents↗
PubMed1996

Isolation of markers for chondro-osteogenic differentiation using cDNA library subtraction. Molecular cloning and characterization of a gene belonging to a novel multigene family of integral membrane proteins.

To identify novel marker molecules associated with chondro-osteogenic differentiation, we have set up a differential screening system based on a cDNA library subtraction in organ cultures of prenatal mouse mandibular condyles. Differential screening of a cDNA library constructed from in vitro cultured condyles allowed the isolation of a novel gene, named E25. Full-length E25 cDNA is predicted to encode a type II integral membrane protein of 263 amino acid residues. In situ hybridization experiments show that E25 is expressed in the outer perichondrial rim of the postnatal mandibular condyle, which contains the proliferating progenitor cells, but not in the deeper layers of the condyle containing the more differentiated chondroblasts and chondrocytes. Other cartilagenous tissues and their perichondrium were negative. Strong in situ hybridization signals were also detected on bone trabeculae of mature bone in tooth germs and in hair follicles. Northern blot analysis showed strong expression in osteogenic tissues, such as neonatal mouse calvaria, paws, tail, and in skin. This expression profile suggests that E25 could be a useful marker for chondro-osteogenic differentiation. Homology searches of DNA databanks showed that E25 belongs to a novel multigene family, containing three members both in man and mouse. The mouse E25 gene locus (Itm2) was mapped to the X chromosome.

Amino Acid Sequence↗
PubMed1978

Condylar metastasis from mammary adenocarcinoma.

A case is reported of metastatic growth in the mandibular condyle from a primary adenocarcinoma of the breast, presenting as painless total trismus of sudden onset. The investigations, treatment and its implications are discussed.

Adenocarcinoma↗
PubMedDate not supplied

Condylar-mandibular asymmetry, a reality.

The aim of this study is to evaluate the possibility to recognize a condylar-mandibular asymmetry through a panoramic radiograph. Results from a previous work, in which 100 skulls from the Museum of the Institute of Anatomy of the University of Pavia were studied and measured, showed the presence of asymmetry. Using the same skulls we examined the possible correlation between morphological and radiological data. We did not find out correlation's between the condylar asymmetry evaluated at the anatomical level and the radiological asymmetry which was indeed found. This is probably due to the different positioning of the jaws during the two different measuring processes. Nevertheless our results confirm the daily experience of dentistry: asymmetry of mandibular condyle can be one of the mayor causes for the asymmetry of the stomatognatic apparatus.

Algorithms↗
PubMed1990

[Metastasis of bronchial carcinoma in the temporomandibular joint. Case report].

Within 35 years 1008 patients were treated that were taken ill in a malignant tumor of face, jaw and mouth. There was found in five patients a distant metastasis of a carcinoma in lower yaw. One case with metastasis in left mandibular condyle is being described. The diagnosis was found by using conventional X-ray examination, Computertomography and aspiration cytology.

Aged↗
PubMed1980

Condylar metastasis from a carcinoma of the prostate gland.

A case is reported of a metastatic lesion of the mandibular condyle which subsequently confirmed a primary adenocarcinoma in the prostate gland. Attention is drawn to the diffuculties of diagnosis in the absence of a pertinent previous medical history.

Adenocarcinoma↗
PubMed2002

Navigation-guided resection of temporomandibular joint ankylosis promotes safety in skull base surgery.

PURPOSE: Computer-assisted surgery (CAS) has not been a routine part of craniomaxillofacial surgery to date. This report investigates the use of CAS to promote the safe removal of ankylosed temporomandibular joint bone in the skull base. PATIENTS AND METHODS: Out of a total pool of experience with 102 navigation-guided CAS procedures between January 1998 and December 2000, we report on 2 cases of navigation-aided resection of severe ankylosis of the mandibular condyle with a predetermined safety margin of the resection toward the middle cranial fossa, and identification of the foramen ovale. RESULT: The use of CAS with navigation resulted in the promotion of safe surgical excision of the ankylosed skull base tissue. CONCLUSIONS: We regard navigation-aided resection of an ankylosis fo the mandibular condyle as a valuable additional technique in this potentially complicated procedure.

Adult↗
PubMed1997

Osteoarthritis in the temporo-mandibular joint (TMJ) of aged mice and the in vitro effect of TGF-beta 1 on cell proliferation, matrix synthesis, and alkaline phosphatase activity.

The temporo-mandibular joint of aged mice develops osteoarthritic (OA) degenerative lesions. Adult chondrocytes have a low rate of cell replication, and cartilage repair potential is very limited. One of the major problems in OA is the low rate of matrix synthesis and the inability of the chondrocytes to exceed the rate of matrix degradation. These combined factors lead to the overall destruction of the cartilage as seen in OA. Cartilage degradation is mediated by elevated proteolytic activity of enzymes. Among the enzymes degrading cartilage are the metalloproteinases, stromelysin and collagenase. Other proteinases that may potentially participate in matrix degradation are the lysosomal enzymes cathepsin B, D, and L, and acid phosphatase. On the other hand, alkaline phosphatase (ALP) is an enzyme that has been shown to be a marker for anabolic activity in skeletal tissues such as bone and cartilage. The cartilage of the mandibular condyle in the T-M-J from aged mice reveals OA lesions. An overall reduction of cell proliferation and sulfated proteoglycan synthesis has been also shown in this joint. In the present study the effects of hTGF-beta on the stimulation of DNA and sulfated GAG synthesis and ALP activity were studied. Mandibular condyle cartilage obtained from 12-month-old ICR male mice were cultured in BGJb serum-free medium for 24-72 hours, supplemented with 0.1-10 ng/ml hTGF-beta 1. 3H-thymidine and 35S-sulfate were added for the last 24 hours of the culture and their incorporation into DNA and sulfated GAGs respectively, as well as the activity of ALP, were determined. Results indicated that hTGF-beta 1 enhanced the incorporation of both 3H-thymidine and of 35S-sulfate into cartilage cultures of aged mice, and also induced ALP activity. It thus appeared that in OA degenerating articular cartilage, the chondrocytes could be stimulated in vitro to proliferate and to synthesize new matrix, thus indicating induced anabolic activity in the tissue.

Alkaline Phosphatase↗
PubMed1997

Tympanic plate fracture following mandibular trauma.

Bleeding from the external auditory canal following head trauma is not unusual. It can be caused by a posterior dislocation of the mandibular condyle associated with a fracture of the tympanic bone. Although posterior dislocation is uncommon, it is the second most frequent complication after antero-medial displacement of the condyle. We report four cases of tympanic plate fracture and present CT images demonstrating the range of injuries seen.

Adolescent↗
PubMed2000

[The diel rhythm of PGE2 in blood of the growing rat after retractive force on mandible].

OBJECTIVE: To study whether the orthopedic therapy will affect the rat's metabolism, the author investigates the diel rhythm of PGE2 in blood of the growing rats before and after retractive force on mandible. METHODS: 72 rats which were 4 weeks old and about 90 g, were divided equally and randomly into three groups: the contrast group were not exerted force, the daytime-forced group were exerted force from 8:00 am to 20:00 pm, the nighttime-forced group were exerted force from 20:00 pm to 8:00 am of the next morning. The backwards force imposed on the rats were exerted through the center of the mandibular condyle and was about 40 g(0.4 N). The period of experimentation was 7 days. In the 8th day, every 4 rats from each of the group were killed respectively at 0:00, 4:00, 8:00, 12:00, 16:00 and 20:00 to collect 3 ml blood. Then radioimmunoassay methods were used to measure the concentration of PGE2 in the blood. RESULTS: In natural state, there was a diel rhythm in the concentration of PGE2 in rats' blood and the diel rhythm was related to that of endogenous PGE2 in condyle; After imposed orthopedic force to restrain mandibular growth, the normal diel rhythm of PGE2 in blood disappeared. There was no significant difference in the time-concentration curves between the contrast group and the daytime-forced group (P > 0.05), but the difference between the contrast group and the nighttime-forced group was obvious (P < 0.05) and the mesor of the nighttime-forced group was greatly decreased. CONCLUSION: The concentration of PGE2 in rats' blood will not be affected by the orthopedic force in daytime, in nighttime. For this reason, not only the therapeutic effect but also the effect on the body's metabolism should be considerd in clinical therapy, and further researches should be carried out on whether the local orthopedic force would influence the metabolism of the whole body.

Animals↗
PubMed1978

Midface deviation due to mandibular fractures. (An experimental study with clinical comparison).

An experimental study was undertaken into the effect of fractures produced in the body of the mandible, the base of the condylar process and the mandibular condyles, on the bones of the middle third of the face using rabbit sucklings. The rabbits were sacrificed when fully grown, when it was found that in all cases the bones of the middle face had deviated to the traumatized side in comparison with the neurocranium. The greatest asymmetry occurred after injuries to the condyles and least following injuries to the body of the mandible. A comparative study on patients past growing age who had had an injury to the condyle before the age of 10 years suggested a similar disturbance of development. The present material, however, was so limited that reliable conclusions could not be drawn.

Animals↗
PubMed1989

Interactions between jaw-muscle recruitment and jaw-joint forces in Canis familiaris.

Electromyographic activity from the jaw-adductor muscles was recorded during mastication and bone crushing in domestic dogs (Canis familiaris). During mastication, balancing-side temporalis electromyographic activity was much less than that of the working side while masseter muscle electromyographic activities were of similar amplitude. Despite the large bite forces that were produced during bone crushing, balancing-side masseter and temporalis electromyographic activities were always smaller than the working-side electromyographic amplitudes. Based upon geometric modelling, it is proposed that balancing-side muscle activity is reduced because of its tendency to produce mechanically disadvantageous jaw-joint forces. This hypothesis was tested by correlating bone strain adjacent to the jaw joint measured during manipulations of the mandibular condyle with bone strain recorded during the simulation and stimulation of jaw-adductor muscle activity. Working-side muscle activity produced bone strain that correlated with a compressive joint loading, while balancing-side muscle activity, with an occlusal fulcrum at the carnassial teeth, produced bone strain indicative of an anteroventral movement of the working-side mandibular condyle which eventually ruptured the joint capsule. When the temporalis and masseter muscles were stimulated bilaterally with a carnassial bite point, bone strain indicative of a ventrally directed and potentially damaging condylar movement was produced. It is proposed that working-side muscle activity exceeds balancing-side muscle activity during carnassial biting to maintain jaw-joint stability.

Animals↗
PubMed2005

Role of magnetic resonance imaging in the clinical diagnosis of the temporomandibular joint.

Temporomandibular joint (TMJ) abnormalities cannot be reliably assessed by a clinical examination. Magnetic resonance imaging (MRI) may depict joint abnormalities not seen with any other imaging method and thus is the best method to make a diagnostic assessment of the TMJ status. In patients with temporomandibular joint disorder (TMD) referred for diagnostic imaging the predominant TMJ finding is internal derangement related to disc displacement. This finding is significantly more frequent than in asymptomatic volunteers, and occurs in up to 80% of patients consecutively referred for TMJ imaging. Moreover, certain types of disc displacement seem to occur almost exclusively in TMD patients, namely complete disc displacements that do not reduce on mouth opening. Other intra-articular abnormalities may additionally be associated with the disc displacement, predominantly joint effusion (which means more fluid than seen in any asymptomatic volunteer) and mandibular condyle marrow abnormalities (which are not seen in volunteers). These conditions seem to be closely related. Nearly 15% of TMD patients consecutively referred for TMJ MRI will have joint effusion, of whom about 30% will show bone marrow abnormalities. In a surgically selected material of joints with histologically documented bone marrow abnormalities nearly 40% showed joint effusion. Disc displacement is mostly bilateral, but joint effusion seems to be unilateral or with a lesser amount of fluid in the contralateral joint. Abnormal bone marrow is also mostly unilateral. Many patients have unilateral pain or more pain on one side. In a regression analysis the self-reported in-patient TMJ pain side difference was positively dependent on TMJ effusion and condyle marrow abnormalities, but negatively dependent on cortical bone abnormalities. Of the joints with effusion only one fourth showed osteoarthritis. Thus, there seems to be a subgroup of TMD patients showing more severe intra-articular pathology than disc displacement alone, and mostly without osteoarthritis. It should, however, be emphasized that patients with TMJ effusion and/or abnormal bone marrow in the mandibular condyle seem to constitute only a minor portion (less than one fourth) of consecutive TMD patients referred for diagnostic TMJ imaging. The majority of patients have internal derangement related to disc displacement, but without accompanying joint abnormalities. In patients with rheumatoid arthritis and other arthritides TMJ involvement may mimick the more common TMDs. Using MRI it is possible, in most cases, to distinguish these patients from those without synovial proliferation.

Adult↗
PubMed2002

Leptin acts as a growth factor on the chondrocytes of skeletal growth centers.

Childhood obesity frequently is associated with an increase in height velocity and acceleration of epiphyseal growth plate maturation despite low levels of serum growth hormone (GH). In addition, obesity is associated with higher circulating levels of leptin, a 16-kDa protein that is secreted from the adipocytes. In this study, we evaluated the direct effect of leptin on the chondrocyte population of the skeletal growth centers in the mouse mandibular condyle, a model of endochondral ossification. We found that chondrocytes in the growth centers contain specific binding sites for leptin. Leptin, at a concentration of 0.5-1.0 microg/ml, stimulated in a dose-dependent manner the width of the chondroprogenitor zone (up to 64%), whereas higher concentrations had an inhibitory effect. Leptin induction of both proliferation and differentiation activities in the mandibular condyle was confirmed by our findings of an increase in bromodeoxyuridine (BrdU) incorporation into DNA and in (acidic) Alcian blue (AB) staining of the cartilaginous matrix. Leptin also increased the abundance of the insulin-like growth factor (IGF) I receptor and IGF-I receptor messenger RNA (mRNA) within the chondrocytes and the progenitor cell population. Our results indicate that leptin acts as a skeletal growth factor with a direct peripheral effect on skeletal growth centers. Some of its effects on the growing bone may be mediated by the IGF system via regulation of IGF-I receptor expression. We speculate that the high circulating levels of leptin in obese children might contribute to their growth.

Animals↗