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PubMed1993

Lectin binding in bone matrix of adult rats with special reference to cement lines.

The present study was designed to localize glycoconjugates recognized by four lectins (LFA, MPA, WGA, and ConA) in adult rat bone, histochemically and biochemically. LFA, a lectin recognizing sialic acid, stained intensely the cement lines of calvariae and the interface between cartilage and bone of mandibular condyles, which were also stained with WGA, and intermittently stained with ConA. The irregular bone surface of calvariae displayed intense positive reaction with LFA and WGA, while the osteoid of mandibular condyles and the smooth bone surface of calvariae were intensely stained with WGA and ConA, but weakly stained with LFA and MPA. MPA recognized osteoclasts. At the superficial layer of mandibular condyles, the bone matrix appeared positive as granules with LFA and as patches with MPA, WGA and ConA. Lectin blotting analysis of bone extracts revealed two LFA positive bands at molecular weights of 18 kDa and 45 kDa. The former was positive with WGA, ConA, and MPA, while the latter was positive with MPA. The result suggests that the LFA-binding glycoconjugates, possibly 18 kDa and/or 45 kDa sialoglycoconjugates, may contribute to cementing mechanism of cement lines and/or to the bone formation in remodeling process as well as in intramembranous and intracartilaginous osteogenesis.

Animals↗
PubMedDate not supplied

Collagen I and II mRNA distribution in the rat temporomandibular joint region during growth.

The distribution of type I and II collagen synthesis in the temporomandibular joint (TMJ) area of 1- to 28-day-old rats was studied after hybridization with probes to pro alpha1(I) and pro alpha1(II) collagen mRNA, and stain intensity through the various cartilaginous zones of the mandibular condyle and other areas of TMJ was assessed. The pro alpha(I) collagen mRNA was detected in the perichondrium/periosteum, in the fibrous and undifferentiated cell layers of the mandibular condyle, in the articular disc, and in all bone structures and muscles. The pro alpha1(II) collagen mRNA was found in the condylar cartilage and the articular fossa. Intensity in the condyle was highest in the chondroblastic layer and decreased towards the lower hypertrophic layer. In the condylar cartilage of the 21- to 28-day-old rats the chondroblastic cell zone was relatively narrow compared with the younger animals, whereas the reverse seems to be the case in the cartilage of the articular fossa. Changes in the pro alpha1(II) collagen mRNA were observed in the osseochondral junction area of the primary spongiosa, in that at the age of 5 days intense staining was found, whereas no staining was observed by 14 days. In the mineralizing zone, however, the majority of osteoblastic cells gave a positive signal with the pro alpha1(I) collagen probe. In conclusion, type II collagen synthesis of the mandibular condyle is restricted to its upper area. This differs from the long bone epiphyseal plate, where this type of collagen is produced virtually throughout the cartilage. Type II collagen synthesis of the fossal cartilage seems to increase as a function of age.

Age Factors↗
PubMed2003

Analysis of mandibular dose distribution in radiotherapy for oropharyngeal cancer: dosimetric and clinical results in 18 patients.

BACKGROUND AND PURPOSE: The relationship between the radiation dose and the risk of the osteoradionecrosis is well known. However, the dose to the mandible is not routinely assessed in the radiotherapy for head and neck cancer. The aim of our study was to analyze the mandibular dose distribution in the patients administered curative radiotherapy for squamous cell carcinoma of the oropharynx. Moreover, the clinical results have been analyzed. MATERIAL AND METHODS: We examined the clinical records and treatment plans in 18 patients treated with bifractionated radiotherapy for stage II-IV oropharyngeal cancer. In 17 patients, the total radiotherapy dose prescribed in the International Committee of Radiation Units and Measurements (ICRU) reference point was 74.4 Gy administered in 62 fractions (1.2 Gy twice daily with 6h interfraction interval) and one patient received a dose of 75.6 Gy. The whole dose to the mandibular-orophryngeal region was delivered with 6 MV photons. The mandible was contoured manually on computed tomographic scans and the point doses at the both mandibular condyles, ascending ramus, mental symphysis, molar and retromolar regions were assessed. Moreover, the cumulative dose-volume histograms (DHVs) were evaluated. The median follow-up period for alive patients is 30 months (range, 21-44+ months). RESULTS: Tumor remission was observed in 17 patients: in 11 cases, complete remission was achieved and in six cases, only partial remission was possible. One patient was lost to follow-up before the first response evaluation. The median survival for all patients is 22 months (range, 3-44+ months). Ten patients are alive and seven died. In six cases, the cause of death was head and neck tumor and in one died due to pancreatic cancer (second primary). No late bone post-radiation complication was seen. The highest radiotherapy doses were observed in the retromolar regions. The mean percentage doses at the right and left retromolar regions were 101.3+/-3.8% (range, 90.2-109.1%) and 101.7+/-2.5% (range, 95.2-105.8%), respectively. Lower doses were seen in ascending ramus (the mean percentage doses at right and left ascending ramus were 97.3+/-8.5% and 97.8+/-7.6%, respectively), the molar regions (the mean percentage doses at right and left molar regions were 86.0+/-13.5% and 88.1+/-12.9%, respectively), and at the mandibular condyles (the mean percentage doses at the right and left mandibular condyles were 72.6+/-18% and 77.0+/-16.5%, respectively). The volume of the mandible ranged from 60.1 to 110.1cm(3) (a mean of of 82.3 cm(3)). In all patients, the maximum dose absorbed in the mandible was higher than the dose prescribed in the ICRU point and the mean maximum dose absorbed in the mandible was 105.7+/-2.1% (range, 102.4-110.6%). The percentage of mandibular volume receiving a dose higher than prescribed was 28.6+/-14.9% (range 10.2-58.1%). The area underlying the DVH curve, the maximum mandibular doses and the retromolar doses did not appear to statistically depend on use of wedge or mandibular volume. CONCLUSIONS: Radiotherapy for oropharyngeal cancer is associated with high doses to the retromolar mandibular regions (the dose can be higher than prescribed in the ICRU reference point), ascending ramus and molar regions. Lower doses are absorbed at the condyles and mental symphysis. The single dose point (for example, the ICRU reference point) could be not used as a representative for the mandibular dose. In our small series of patients treated with hyperfractionated irradiation, these dose heterogeneities were not correlated to the patient- and treatment-related factors and are not related to the increased risk of late bone complications. The clinical relevance of mandibular dose distribution remains to be established in larger series of patients treated with conventionally and unconventionally fractionated irradiation.

Adult↗
PubMedDate not supplied

[Bone scintiscan of the mandible after tension bolt osteosynthesis of condylar fractures].

Bone scintiscans were performed in 11 patients with dislocation fractures of the mandibular condyle after reduction of the fractures and fixation of the condyles by tension bolt osteosynthesis. Since the storage of the radioisotope in the bone tissue is directly dependent on the blood circulation, these examinations allow conclusions as to the blood supply of the mandibular condyle head following reduction. No negative effects on blood supply resulting from the operative intervention could be observed.

Bone Screws↗
PubMed1980

The gestalt of occlusion--A clinical appraisal.

1. Occlusion, with its many ramifications, cannot be over simplified. It should not be considered so varied that a sequential and subtle analysis of its ramifications defies simplification. 2. The same mechanisms produce the correct or incorrect physiologic position of the dental units. A faulty mechanism must be recognized and all efforts made to return it to efficiency as soon as possible for the benefit of the entire system. 3. The correct physiologic terminal position of the mandibular condyles is the ideal relationship in the TMJ and activates the posterior component forces of the neurologic system. This forms the dentition into its most harmonious relationship. 4. Any teminal position of the condyle in the mandibular fossa, other than the physiologic terminal position, compromises the potential of a harmonious interdental forming process. The results range from simple deflective occlusal contacts to severe malocclusions. 5. The constancy of the occlusal plane relationship, easily determined from a cephalometric tracing offers a clinical guide as to its best functioning position. 6. A TMJ radiographic technique that ensures repeatable, reproducible, and traceable radiograms is an essential diagnostic aid. It is necessary to know the position of the condyle in the fossa before, during, and after procedures that alter the interocclusal relationship. 7. Not all TMJ problems are necessarily symptomatic. Occlusal adjustment procedures should be utilized to ensure a harmonious interocclusal relationship manifest by the muscles of mastication functioning in a nonsymptomatic, optimal, and physiologic manner, in all working jaw relations. The ideal physiologic terminal position must be established as closely as possible during saliva swallowing. 8. Only occlusal adjustment techniques utilizing the natural forces of the neuromuscular system to reestablish the ideal physiologic terminal position within the TMJ should be used. A technique such as that developed by Long satisfies this requirement. 9. Although there are many imperfections in knowledge, there are no imperfections in truth.

Cephalometry↗
PubMed1999

Condylar fractures during growth: follow-up of 16 patients.

Fractures of the mandibular condyle represent 20% to 35% of all mandibular fractures. There are several clinical variants of this type of fracture that give rise to different problems in relation to their classification and treatment. A sample of 16 patients (of a total of 280 patients examined and treated from 1985 through 1995) with mono- and bilateral, displaced and decomposed, condylar fractures that occurred during growth were examined by the authors, who assessed, by a 2-year follow-up, the relevant clinical, functional, and instrumental parameters. On the basis of the data gathered by this study, a plan was drawn up for treating these patients that takes into account the different situations, such as either a nonsurgical or surgical treatment (by the use of condylectomy or external rigid fixation), and points out the advantages and disadvantages of each method.

Adolescent↗
PubMed1998

[Relationship between aging and morphological bone changes of the condyle in temporomandibular disorders].

In order to clarify the clinical significance of morphological bone changes of the mandibular condyle in temporomandibular disorders, the relationship between radiographic bone changes and aging was clinically studied. The subjects of the study were 1,120 patients (812 females and 308 males). The average age was 33 years +/- 15 years (from 10 to 81 years of age). The 1,120 patients were divided into six age brackets (10 to 19 years, 20 to 29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, 60 to 81 years). According to radiograms taken by lateral oblique transcranial projection, orbitcondyle projection and orthopantomography, the morphological bone changes were classified into seven groups, erosion, osteophyte, eburnation, flattening, deformity, concavity and sclerosis. The results were as follows: 1. The incidence of the patients with radiographic bone changes of the mandibular condyle increased with aging and showed significantly different age distribution from that without bone changes (Mann-Whitney U test: p < 0.01). 2. The incidence of erosion did not increase with aging and showed significantly different age distribution from osteophyte or eburnation (Mann-Whitney U test: p < 0.01, 0.05). The incidence of flattening also did not increase with aging and showed significantly different age distribution from osteophyte, eburnation or deformity (Mann-Whitney U test: p < 0.01, 0.05, 0.05).

Adolescent↗
PubMed1996

[Experimental research on the distribution of insulin in condyle during mandibular functional protrusion in growing rats].

The purpose of this study is to evaluate insulin change in condylar cartilage during functional advancement of rat mandible by immunohistochemical technique (ABC method) in order to provide further information about the role of insulin in orthopedics and the relationship between insulin and proliferation of condylar cartilage. Staining gradient of insulin is observed in condylar cartilage, with the stain deepest in the geriminal layer, medial in the transitional, least in the maturational layer. The posterior region of condylar cartilage in the experimental groups is shown to have thickened significantly as compared with the control groups, especially the germinal layer. Stained-positive cells exhibit deeper stain and higher percentage. The stain in the other layers is also more obvious than that in the control groups. The results suggest: Insulin level in condyle changes with the different cartilage layers. Insulin distribution appears higher when condylar chondrocytes proliferate rapidly and lower when they differentiate actively. Functional orthopedics may stimulate the growth of condylar cartilage and raise the insulin level. The demonstrates that insulin correlates with hyperplasia of conylar chondrocytes.

Animals↗
PubMed2003

[Localization and registration of the hinge axis in black Africans].

The study of the cinematic method using "SAM" and "Quick Axis of FAG" added to mandibular condyle palpation for the hinge axis limited points, show that the Black Africans mandibular condyle rotation axis position is higher (3.5 mm) and backer (2 mm) than the Caucasians. The axial points are located to between 11 and 12 mm in front of the tragus and between 7 and 8 mm below on the perpendicular line to the furrow defining the tragus superior side to the Ectocanthus.

Adult↗
PubMed1997

[Fractures of the condylar process].

Fractures of the mandibular condyle are frequently seen. There is no consensus on the most appropriate treatment modality. Closed reduction with help of arch bars and guiding elastics is in most cases sufficient. Open reduction and fixation with a plate osteosynthesis or a specially designed lag screw is occasionally performed. Intracapsular fractures of the condylar head are only operated in case of severely reduced mobility, or ankylosis. Fractures of the mandibular condyle normally heal uneventfully. Complications mostly occur in bilateral condylar neck fractures, or intracapsular fractures.

Ankylosis↗
PubMed2005

Fibula flap reconstruction of the condyle in disarticulation resections of the mandible: a case report and review of the technique.

Segmental resection of the mandible with disarticulation of the temporomandibular joint is occasionally required in the management of extensive tumors. The reconstruction of these deformities is complex, frequently involves staged procedures, and may result in significant deformity and loss of function for patients. The fibula free flap has become a standard treatment option for primary restoration of segmental mandibular deformities. However, little is published about its role in reconstructing the mandibular condyle. This paper describes a simplified technique for primary reconstruction of mandibular defects, including the mandibular condyle, in disarticulation resections of the mandible utilizing the fibula free flap.

Adult↗
PubMed2001

The accuracy of sonography for evaluation of internal derangement of the temporomandibular joint in asymptomatic elementary school children: comparison with MR and CT.

BACKGROUND AND PURPOSE: In order to clarify the incidence and evolution of disk displacement in the temporomandibular joint (TMJ) in children, we performed a longitudinal analysis in 18 subjects. Some investigators have suggested that sonography can provide information about the articular disk position of the TMJ. The purpose of this study was to determine the diagnostic accuracy of sonography for revealing internal derangement of the TMJ in elementary school children compared with our standard of reference, MR imaging and helical CT. METHODS: Eighteen children were examined using both sonography and MR imaging or helical CT or both. The sonographically revealed distance between the articular capsule and the lateral surface of the mandibular condyle was measured and compared with that obtained by MR or helical CT scanning. RESULTS: Compared with our MR/CT standard of reference, sonography revealed a sensitivity of 83%, a specificity of 96%, and an accuracy of 92% for identifying disk displacement (defined as a distance of 4 mm or more between the articular capsule and the lateral surface of the mandibular condyle). CONCLUSION: Although sonography's sensitivity, specificity, and accuracy for the diagnosis of disk displacement were slightly inferior to those of MR or helical CT, we assert it is a useful imaging method for longitudinal investigations of a large group of elementary school children. Internal derangement of the TMJ should be suspected if sonography reveals a distance between the articular capsule and the lateral surface of the mandibular condyle of 4 mm or more.

Child↗
PubMed1983

Centric relation as the treatment position.

Centric relation should be considered as "the most superior position of the mandibular condyles with the central bearing area of the disk in contact with the articular surfaces of the mandibular condyles and the articular eminences." This relationship is justifiable on analysis of the morphology and function of temporo-mandibular joint structures.

Cartilage, Articular↗
PubMed1994

A case of open bite accompanied by temporomandibular joint disorder. A comparison of occlusal conditions before and after treatment in lateral-oblique radiogram.

According to the authors' clinical experience, malocclusion accompanied by temporomandibular joint disorder involves mainly cross bite, open bite, deep overbite or axillary protrusion. However, it is possible that the symptoms of this disorder are associated with other types of malocclusion or even with nearly normal occlusion. In fact, it can be said that temporomandibular joint disorder may develop with any type of occlusion. This paper reports a case of open bite accompanied by temporomandibular joint disorder occurring in a patient who visited our hospital because of pain in the left temporomandibular joint region, vertigo and partial deafness. In this patient, the temporomandibular symptoms disappeared after orthodontic treatment. The patient received no particular treatment thereafter because follow-up observation confirmed that the therapeutic results were favorable without any relapse of the symptoms of temporomandibular disorder. The positions of the temporomandibular joint and mandibular condyle were determined in lateral-oblique radiograms obtained using our radiographic system, by which the mandibular condyle is radiographed using a projection consistent with its long axis.

Adult↗
PubMed2002

Morphological influence of ascorbic acid deficiency on endochondral ossification in osteogenic disorder Shionogi rat.

The influences of chronic deficiency of L-ascorbic acid (AsA) on the differentiation of osteo-chondrogenic cells and the process of endochondral ossification were examined in the mandibular condyle and the tibial epiphysis and metaphysis by using Osteogenic Disorder Shionogi (ODS) rats that bear an inborn deficiency of L-gulonolactone oxidase. Weanling male rats were kept on an AsA-free diet for up to 4 weeks, until the symptoms of scurvy became evident. The tibiae and condylar processes of scorbutic rats displayed undersized and distorted profiles with thin cortical and scanty cancellous bones. In these scorbutic bones, the osteoblasts showed characteristic expanded round profiles of rough endoplasmic reticulum, and lay on the bone surface where the osteoid layer was missing. Trabeculae formation was deadlocked, although calcification of the cartilage matrix proceeded in both types of bone. Scorbutic condylar cartilage showed severe disorganization of cell zones, such as unusual thickening of the calcification zone, whereas the tibial cartilage showed no particular alterations (except for a moderately decreased population of chondrocytes). In condylar cartilage, hypertrophic chondrocytes were encased in a thickened calcification zone, and groups of nonhypertrophic chondrocytes occasionally formed cell nests surrounded by a metachromatic matrix in the hypertrophic cell zone. These results indicate that during endochondral ossification, chronic AsA deficiency depresses osteoblast function and disturbs the differentiation pathway of chondrocytes. The influence of scurvy on mandibular condyle cartilage is different from that on articular and epiphyseal cartilage of the tibia, suggesting that AsA plays different roles in endochondral ossification in the mandibular condyle and long bones.

Animals↗
PubMed1995

Gradient-echo MR imaging of the temporomandibular joint: diagnostic pitfall caused by the superficial temporal artery.

OBJECTIVE: In routine MR imaging of the temporomandibular joints, a low-signal structure posterosuperior to the mandibular condyle is occasionally seen on the two-dimensional gradient-echo sequence. The structure is ovoid and may have a higher-signal core, simulating a loose body within the joint. We undertook a clinical and cadaveric study to determine the cause of this finding. MATERIALS AND METHODS: In a clinical study, we reviewed the MR images of 100 temporomandibular joints. We scored each joint for the presence and appearance of a low-signal structure posterosuperior to the mandibular condyle: type 1 was ovoid with a low-signal rim and a higher-signal core, type 2 was ovoid with uniformly low signal, type 3 was a low-signal structure inseparable from the posterior wall of the glenoid fossa, and type 4 was normal. Using this scoring system, we determined the appearance and frequency of the finding on two-dimensional gradient-echo, T1-, T2-, and proton density-weighted images. To determine the cause of the finding, we correlated the imaging and anatomic findings in a cadaveric specimen. RESULTS: Of the 100 MR images of joints reviewed, 22 showed a type 1 structure, 24 a type 2 structure, 11 a type 3 structure, and 43 were normal. The finding was seen only on the two-dimensional gradient-echo sequences, never on the spin-echo sequences. Correlation between the imaging and anatomic findings in the cadaveric specimen showed that the finding was caused by the superficial temporal artery. The variability in its appearance is thought to result from the complex manifestations of flowing blood within this artery. CONCLUSION: The finding posterosuperior to the mandibular condyle seen on two-dimensional gradient-echo MR images is a flow phenomenon within the superficial temporal artery. Recognition of the nature of this finding will avoid mistaking it for disease, such as an intraarticular loose body.

Adult↗
PubMed2006

Skeletal changes after experimentally displaced condylar process fracture in growing rats.

INTRODUCTION: Fractures of the mandibular condyle are common. A potential for growth disturbances in young individuals has been reported; however, there are few experiments studying such consequences. Skeletal changes after fracture of the condyle in the growing period were analysed in this study. MATERIAL: Fifty young Wistar rats weighing 100g were used. Under general anaesthesia unilateral fracture dislocations of the condylar process were induced surgically in the experimental group (n=25), while only surgical access was performed in the sham-operated group. The animals were sacrificed at 3 months of age. The mandibles were disarticulated, and radiographs were taken (axial skulls and lateral hemimandibles). Cephalometric evaluations were made using a computer system. Statistical tests were applied between groups and contralateral sides in each group. RESULTS: There were atrophy and degenerative change of the fractured condylar process. There was also a significant difference in the height of the mandibular body and in the length of anterior and posterior maxilla. CONCLUSION: It was concluded that an experimental fracture of the mandibular condyle during the growing period in rats induced degenerative changes of the condyle as well as an asymmetry of the mandible, affecting height of the body, also leading to consequences in the maxilla.

Animals↗