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Traumatic mandibular condyle dislocations into the middle cranial fossa are rare. Thirty-three cases of middle cranial fossa injuries caused by condylar dislocations have been reported in the literature. A case report of a patient with a traumatic dislocated condyle into the middle cranial fossa, which was treated conservatively, is presented.
UNLABELLED: Anatomic variations in the condylar morphology, like bifid mandibular condyles, are a relatively uncommon anomaly. We report four cases (two in patients and two in archived specimens) of bifid mandibular condyles with emphasis on their aetiopathogenesis and radiographic features. A case of bifid mandibular condyles in a patient with rheumatoid arthritis is reported which, to the best of our knowledge, is the first reported case in the literature. CLINICAL RELEVANCE: Anatomical variations, like bifid mandibular condyles, may mimic a fracture/tumour. Therefore, knowledge and awareness about this entity is important for a general dental practitioner.
Lateral displacement of the intact mandibular condyle is a rare entity, first described in detail and classified into two types (type I, type II) by Allen and Young in 1969. We experienced a rare case of type II lateral dislocation of the bilateral condyles with fracture of other parts of the mandible. It is reflected that delayed closed reduction gave an imperfect result, inducing ankylosis. Bilateral condylectomy with reconstruction of the head using costal cartilage was performed subsequently to improve arthropathy, with a 2-year satisfactory follow-up. A review of the literature shows that there are three types of type II lateral dislocations of the mandibular condyle, which are further related to the technical difficulty of reduction. We propose a new typing of type II lateral dislocations of the mandibular condyle. The clinical assessment for this condition is early reduction. Rather, open reduction is more definitive. However, unavoidable delay in reduction induces ankylosis of the joint, which sometimes necessitates condylectomy with or without arthroplasty.
OBJECTIVE: To audit a series of isolated unilateral fractures of the mandibular condyle treated in a number of units in the United Kingdom. DESIGN: Prospective confidential multicentre audit with review by a single external examiner between July 1993 and January 1994. SETTING: Nine Maxillofacial units. Pro-formas were alphanumerically coded. Units are referred to by code letter. SUBJECTS: 142 patients with fractures of the mandibular condyle. MAIN OUTCOME MEASURES: Pain, crepitus, interincisal opening, mandibular deviation on movement, occlusion and posteroanterior and lateral radiographic analysis by a single examiner. RESULTS: Of the 142 patients, 135 over the age of 12 years had unilateral condylar fractures. Seventy-three attended appointments at both 6 and 12 weeks. Forty-one had identifiable symptoms attributable to the injury at 12 weeks, and most of these had fracture displacements or dislocations which had not been openly reduced. There was a 50-85% positive correlation between radiographic findings of the first clinician and the external auditor. Open reduction and internal fixation was uncommon. CONCLUSIONS: Follow-up studies of trauma patients are difficult because of poor attendance. Fractures of the mandibular condyle should be treated by specialists in the management of facial fractures. Accurate clinical and radiographic diagnosis is more difficult than commonly supposed. Fracture displacements and dislocations have a suboptimal outcome in nearly 30% of cases. More should be spent to improve care of these patients. A consensus on objective indicators of satisfactory outcome is needed to establish a 'gold standard' and close the audit loop.
A case of supplemental mandibular condyle is presented and possible aetiological factors are discussed. The value of computed tomography and of scintigraphy in the diagnosis of such cases is illustrated and surgical and histological details of an excised supplemental condyle are presented for the first time.
The purpose of this study was to investigate the functional characteristics of human mandibular condyles from a morphological viewpoint. The structure of bone in the human mandibular condyles with osteophyte formation was observed macroscopically and microscopically and compared with that in the condyles which seemed to be normal. The following observations were made: 1. Generally, it was observed that remodeling seemed to occur frequently in compact bone in the joint surface area of the mandibular condyle. 2. As the distribution of lamellar bone, nonlamellar, and bundle bone in the joint surface area changes, the compact bone seems to shift down and protrude forward. In larger osteophytes, trabeculae of cancellous bone-like structure are observed. However, the basic structure of compact bone, including haversian system and the interlamellae structure remains within the trabecullae. Therefore, observation revealed histologically that this is a compact bone. The macroscopical appearance of cancellous bone-like structure seems to be a result of functional demand. 4. It was concluded that the mandibular condyles accommodate the functional loads, and adoptational changes occur constantly in a stable manner.
Osteochondroma of the mandibular condyle is extremely rare. An unusual case of a 32-year-old man is reported. Throughout a two-year period the patient suffered from intractable pain in the left T. M. J. region, anterior dislocation of the condylar head, malocclusion and facial asymmetry. Radiologic examination revealed that the cartilaginous cap of an overgrowth had functioned as an articular cartilage. A "pseudo articulation" was created with the prominent articular eminence and allowed an almost free movement of the mandible. Review of the seven reported cases revealed that the rare occurrence, natural history, clinical course and lack of recurrence of osteochondroma of the condylar process all substantiate the contention that this overgrowth must be considered as an osteocartilaginous exostosis rather than a neoplasm.
In the mandibular condyle of the newborn mouse the chondroprogenitor (CP) zone is the only layer that incorporates 3H-thymidine thus serving the source for cells of the cartilage lineage. Ultrastructurally these cells have a mesenchymal appearance surrounded by collagen fibrils as well as by additional filaments that become apparent following fixation with ferrocyanide-reduced OsO4. In addition, electron-dense particles indicative of proteoglycans are scattered throughout the matrix in the CP zone as well as in the chondroblastic and hypertrophic zones. Following labeling with 35S-sulfate the CP zone as well as the other compartments revealed a substantial number of grains following processing for autoradiography. The number of grains per cell was highest in the hypertrophic zone. Indirect immunofluorescence indicated the presence of fibronectin in the articular surface, CP zone and in the hypertrophic zone. The immunogold method localized fibronectin intracellularly in CP cells and extracellularly in the hypertrophic zone. Therefore, in the mandibular condyle the CP cells which are capable for DNA synthesis are also involved in the synthesis of macromolecules of which some are specific for the cartilage phenotype, while others are associated with other functions of connective tissue cells.
A case of supero-lateral dislocation of the mandibular condyle into the temporal fossa is reported. The condyle was concurrently fractured antero-posteriorly forming a bifid mandibular condyle. The previously reported cases of supero-lateral dislocations into the temporal fossa are discussed and the literature of bifid condyle is reviewed.
PURPOSE: This study examines the pullout forces and the modes of pullout for the Mitek mini and micro suture anchor systems (Mitek Inc., Norwood, MA) when inserted into the posterior aspect of the condyle. MATERIAL AND METHODS: Twenty mandibular condyles were obtained from embalmed human cadavers. A mini anchor and a smaller micro anchor were threaded with braided size 0 and 3-0 polyester suture, respectively, and placed in the posterior aspect of each condyle. Pullout testing was performed using an Instron materials testing machine. The force and mode of pullout were recorded for each specimen. RESULTS: The findings indicate a significantly greater mean pullout force of 16.02 lbs for the larger mini anchor system as compared with the 10.57 lbs mean pullout force of the micro anchor system. The modes of pullout between these implants were also different. Intact mini suture anchor systems pulled through the cortical bone in 90% of the trials, and suture breakage occurred in 10%. The micro anchors were irreversibly deformed on pullout in 65% of the trials, whereas the suture broke in 25% of the trials, and the intact suture anchor system pulled through the cortical bone in 10%. CONCLUSIONS: The Mitek mini anchor system has a significantly greater pullout force from the mandibular condyle than the micro anchor system.
The purpose of the present study was to investigate histologically and histometrically the effect of experimental unilateral traumatic occlusion (right side) on the mandibular condyle in rats. 1. Histological findings of the periodontal tissues. i. Group A (Control Group) Periodontal tissues of the right mandibular first molar: Throughout the entire experimental period, a normal structure was observed. ii. Group B (1 mm Group) Periodontal tissues of the right mandibular first molar: At 1 and 2 weeks, resorption of the dentin and cementun, irregular arrangement of the periodontal fibers, resorption of the alveolar bone, and widening of the periodontal space were observed. At 3 and 4 weeks, these changes were gradually repaired. At 8 weeks, the changes were almost repaired except the change of the alveolar bone. Periodontal tissues of the left mandibular first molar: Throughout the entire experimental period, no changes were found. iii. Group C (2 mm Group) Periodontal tissues of the right mandibular first molar: At 1 and 2 weeks, resorption of the dentin and cementum, irregular arrangement of the periodontal fibers, necrosis of the periodontal ligament, resorption of the alveolar bone, and widening of the periodontal space were observed. These changes were more marked than those of the same molar in Group B. From 3 to 8 weeks, the changes were similar to those of the same molar in Group B. Periodontal tissues of the left mandibular first molar: Throughout the entire experimental period, no changes were found. 2. Histological and histometrical findings of the mandibular condyles. i. Group B (1 mm Group) Right mandibular condyle: The layers of differentiation and hypertrophy showed a marked decrease in thickness and cellularity at 4 and 8 weeks. The layer of cartilage decreased significantly in thickness at 4 and 8 weeks (p less than 0.01). The cancellous bone showed a marked widening of bone marrow spaces at 4 and 8 weeks. It also decreased significantly in volumetric density at 4 and 8 weeks (p less than 0.01 or p less than 0.05). Left mandibular condyle: The layers of differentiation and hypertrophy showed a marked decrease in thickness and cellularity at 4 and 8 weeks. The layer of cartilage decreased significantly in thickness at 4 and 8 weeks (p less than 0.01). ii. Group C (2 mm Group) Right mandibular condyle: The layer of articular surface showed a marked decrease in cellularity at 1, 2, 3 and 8 weeks. It also decreased significantly in thickness at 1, 2, 3 and 8 weeks (p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
Changes in cancellous bone of the rat mandibular condyle following estrogen deficiency were histomorphometrically examined with 120-day-old female Fischer rats. Sixty-four animals were either ovariectomized bilaterally (ovx) or subjected to sham surgery (sham), and eight from each group were killed at 7, 14, 30, and 60 days after surgery. Seven intact animals were killed on day 0. Before killing, tetracycline and calcein were administered to all animals. Following histological observation, bone histomorphometry of the mandibular condyle was done using a confocal laser scanning microscope and an image analyzer. The sampling site was divided into two regions for analysis: (1) a "subchondral region," formed by the region connected to cartilage; and (2) a "central region," formed by the region beneath the former. The changes in these two regions were analyzed separately. In the sham group's condyle, the bone volume of the subchondral and central regions increased with the passage of time, although the bone turnover became low. This bone gain could be due to the effects of growth and the mechanical stimulus by occlusal load. In the subchondral region of the ovx group's condyle, the bone volume decreased significantly at 7 days, but recovered to reach approximately the same value as the sham group from 14 days onward. In the central region of the ovx group's condyle, the bone volume was unchanged, but revealed a significantly lower value than that of the sham group at 60 days (p < 0.01). Thus, ovariectomy inhibited bone gain, which was observed in the sham group's condyle even though there was no bone loss. On the other hand, the trabecular separation in the ovx's condyle of both the subchondral and central regions increased considerably and small marrow cavities interconnected to form a large bone marrow. Therefore, the ovx rat mandibular condyles dynamically altered their structures under the effects of estrogen deficiency and occlusal loads. Consequently, estrogen deficiency induced transient subchondral bone loss and recovery, whereas, in the central region, it inhibited bone gain. This suggests that mechanical loading modulates the normal ovx-induced bone loss found in other parts of the skeleton.
The mandibular condyle is a major growth site and is known to adapt to functional factors. Numerous studies have been performed on the effects of growth factors on the metabolism of primary cartilages, but only a few investigations have examined their action on primary and secondary cartilages. Therefore, the purpose of this study was to compare the effects of insulin-like growth factor-I (IGF-I), transforming growth factor-beta(1) (TGF-beta(1)), and fibroblast growth factor-2 (FGF-2) on the growth of secondary cartilage from the mandibular condyle and primary cartilage from the femoral head of new-born rats. In addition, synergy between these growth factors was investigated. The level of glycosaminoglycan (GAG) and DNA synthesis was analysed after 5 days in culture with the growth factors. The effects of TGF-beta(1) and FGF-2 on growth, tissue organization, and the GAG and collagen content were also evaluated. The stimulation of cell proliferation by the growth factors was higher in the mandibular condyles than in the femoral heads. The content of the matrix components was reduced more by FGF-2 in the mandibular condyles than in the femoral heads. Both TGF-beta(1) and FGF-2 antagonized the stimulatory effects of IGF-I on GAG synthesis in the two types of cartilage. In contrast, the total growth of mandibular condyles was not affected by TGF-beta(1) and FGF-2 while that of femoral heads was strongly reduced. This was mainly due to the inhibition of chondrocyte hypertrophy. These results show that in spite of the extensive effects of growth factors on the metabolism of mandibular condyles, their dimensional growth was not affected.
A few cases of bifid, but no case of trifid mandibular condyle, have been reported in the literature. This article presents the first reported case of trifid mandibular condyle in a living subject with a history of previous trauma to the temporomandibular joint (TMJ). Additionally, the patient's other condyle was bifid. The patient had no complaint related to the functions of TMJ except for minimal weakness following chewing. The etiology and the prognosis of bifid and trifid condyle are discussed briefly. We considered computed tomography essential to rule out early stages of TMJ pathology in similar cases that resemble trifid mandibular condyle on conventional radiographs.
The purpose of this study was to identify the effects of the local administration of cyclophosphamide (CP) on mandibular condyle growth in growing rats. Sixty three 4-week old male Sprague Dawley rats were used in this study. In the experimental group, CP (50 mg/ml) 0.02 ml was injected into both articular capsules of the condyle, while the control group was injected with physiological saline (Experiment I). Histological observation: The animals were sacrificed either at 3, 5, or 7 days after injection of CP or physiological saline. The condyles were extracted and the sections were prepared for histological and histomorphometric observations. The number of BrdU positive cells, the number of osteoclasts, the thickness of the cartilage layer and the amount of endochondral bone growth in the condyle were measured (Experiment II). Morphological observation : 4-week-old male Sprague-Dawley rats were grouped into control group, CP (25 mg/ml) treated group, and CP (50 mg/ml) treated group. These injections were performed one time at 7-day intervals, and then all rats were killed on the 7 th day after the last injection. The effects of CP local administration on the mandible were investigated morphologically using cephalometric analysis. In experiment I, there was a significant decrease in the BrdU positive cells, the thickness of the cartilage layer, and the amount of endochondral bone growth in the experimental group. In experiment II, the condyle of the CP (50 mg/ml) treated group was significantly shorter than that of the control group. These results demonstrate that local administration of CP into growing condyle inhibited mandibular condyle growth.
The purpose of this study was to investigate the relationship between food consistency and the growth of the mandibular condyle in rats. Secondly, the effect of dental extractions on cartilage of the mandibular condyle was examined in young adult rats fed foods of varying consistency. Thirty-six male Wistar rats were divided into four groups: (A) Solid diet--non-Extraction (non-Ext.) group; (B) Solid diet--Extraction (Ext.) group; (C) Powder diet--non-Ext. group; and (D) Powder diet--Ext. group. Extractions were performed at 12 weeks of age. The mandibular condyles were removed at 1, 4, and 8 weeks after the extractions. The shape of the mandibular condyles in the powder diet groups (C and D) was significantly narrower. In the Ext. groups (B and D), the thickness of the hypertrophic zone was reduced one week after the extractions. In the powder diet groups (C and D), the intensity of the staining of fibronectin decreased in the proliferative zone regardless of the extractions. In group B, a decreased intensity of this reaction was observed one week after the extractions. From these results, it appeared that food consistency and/or dental extractions affected the morphology of the mandibular condyle and the histological characteristics of the mandibular condylar cartilage.
PURPOSE: To determine the morphology and the frequency of bifid mandibular condyle (BMC) in anatomic material and to study its diagnosis in living persons. MATERIAL AND METHODS: The morphology and the frequency of BMC were studied on a sample of 210 intact mandibular condyles belonging to a collection of 200 dry male adult skulls held by the Institute of Anatomy of University of Bologna. Diagnostic imaging was verified retrospectively on 6 cases of BMC observed in living subject. RESULTS: In the anatomic material, we found 29/210 mandibular condyles with the articular surface simply parted in two (13.80%) and 1 condyle consisting of two separate articular heads (0.47%) at different levels and without the neck. Therefore BMC with separate neck is very rare. In living persons diagnosis was established by radiology using orthopantomography and demonstrated 2 cases of bilateral BMC (one dysplasic and the other traumatic) and 4 of unilateral BMC. DISCUSSION AND CONCLUSIONS: We believe that primitive BMC is a consequence of a dysplasic process of the condyle cartilage at the early stages of its development, while secondary traumatic BMC is caused by bone remodelling after articular trauma or repeated microtraumas from malocclusion. In dysplasic BMC, as evidenced by the observation made on a living subject, a distinction should be made between the complete type in which the accessory articular head is separate from the principal head, at a different level and with its own separate neck, and the other, incomplete types. Orthopantomography, which proved to be a valid diagnostic tool, must be integrated with CT and MR if surgery is planned.
OBJECTIVE: In a previous study, we named the magnetic resonance imaging (MRI) signal that is characteristic of mandibular condyles in growing children the "double contour-like structure" (DCLS). In the current study, we evaluated the alternating appearance and disappearance of the DCLS in children as they grow to elucidate the significance of the DCLS. STUDY DESIGN: In 11 subjects who were 9-14 years old at the time of the first examination, MRI characteristics of mandibular condyles were sought from fast spin-echo intermediate-weighted images; 2 or 3 years later, repeat MRI were obtained from the same subjects. RESULTS: At the second examination, 10 of the 16 DCLSs detected at the first examination had disappeared. A significant relationship was found between the alternation of the DCLS and the bone marrow conversion from red to yellow in mandibular condyles. Alternation of the DCLS tended to coincide with eruption of the permanent maxillary second molars. The DCLS was also shown to appear as a hypersignal on T2-weighted images. CONCLUSIONS: Double contour-like structure signals in mandibular condyles appeared and disappeared as children grew, and these signal alternations may be useful as a criterion for the staging of mandibular condyle development in children. Possible constituents of the DCLS may be hypervascular loose fibrous tissue and a proliferation of cartilage.