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This article reviews the anatomy and surgical approaches for treating fractures of the mandibular condyle with plate and screw fixation. Advantages and disadvantages of the preauricular, submandibular, intraoral, retromandibular, and rhytidectomy approaches are presented.
Since edentate subjects have a reduced masticatory function, it can be expected that the morphology of the cancellous bone of their mandibular condyles has changed according to the altered mechanical environment. In the present study, the morphology of cylindrical cancellous bone specimens of the mandibular condyles of edentate subjects (n = 25) was compared with that of dentate subjects (n = 24) by means of micro-computed tomography and by the application of Archimedes' principle. Stiffness and strength were determined by destructive mechanical testing. Compared with dentate subjects, it appeared that, in edentate subjects, the bone was less dense and the trabecular structure was less plate-like. The regression models of stiffness and strength built from bone volume fraction and the trabecular orientation relative to the axis of the specimen were similar for both dentate and edentate subjects. This indicates that, under reduced mechanical load, the fundamental relationship between bone morphology and mechanical properties does not change.
Surface features of the human mandibular condyle have been studied by scanning and electron microscopy. Normal condyles possessed features similar to those in other diarthrodial joints but with certain differences. Two types of erosion and an exostosis were seen in diseased joints and the surface structure is described.
Long-term result of conservative and surgical treatment of varying types of mandibular condyle fracture in 34 cases was investigated. The study shows that 90% cases of condyle fracture, including that complicated with dislocation and displacement, could be successfully treated with simple immobilization by intermaxillary elastic bands. The long-term result of close reduction is closely related to the interval between the trauma and the start of treatment, the earlier the beginning of the treatment, the better the result. The unfavourable immediate result in form of imperfect occlusion and excursion, etc. could be corrected by forced mandibular movement. 10 cases complicated with badly dislocation or communicated fracture were treated with condylectomy, satisfactory results were achieved in 80% of them.
A case of osteochondroma of the mandibular condyle has been presented, along with a review of the features of this lesion. A consideration of immediate condylar replacement after benign tumor surgery of the condyle is discussed.
Malocclusion and disharmony of facial growth are the usual results of injury to the mandibular condyle in children. Early replacement of the condyle with a skeletal growth centre such as the costochondral junction is postulated as one approach to management of such problems. This paper describes the results of such transplantations in ten growing children where there had been either ankylosis or excision of the condyle. Long term follow-up evaluation shows lack of uniformity in the subsequent growth of the transplants. Nevertheless, significant growth of the transplants is demonstrated in some of the patients. The data lends support to the principle that bony growth centres are in part responsible for the growth and maturation of the facial skeleton.
Three cases of intracranial penetrations of the mandibular condyle condyle are reported, the published literature reviewed, and therapy discussed. Often unrecognized during initial examinations, they are diagnosed when the patient is seen several months later with permanent constriction of the jaws. Frontal and sagittal tomographic examinations should therefore be performed in the articular region in all cases when it is involved in injuries. Orthopedic reduction gives good results in recent injuries, long-standing cases with temporomandibular ankylosis requiring sub-condylar resection by the pre-auricular approach.
OBJECTIVE: To investigate the influence of decreased mechanical loading on the density and mechanical properties of the cancellous bone of the human mandibular condyle. DESIGN: Destructive compressive mechanical tests were performed on cancellous bone specimens.Background. Reduced masticatory function in edentate people leads to a reduction of forces acting on the mandible. As bone reacts to its mechanical environment a change in its material properties can be expected. METHODS: Cylindrical bone specimens were obtained from dentate and edentate embalmed cadavers. Mechanical parameters were determined in the axial and in the transverse directions. Subsequently, density parameters were determined according to a method based on Archimedes' principle. RESULTS: The apparent density and volume fraction of the bone were about 18% lower in the edentate group; no age-related effect on density was found. The decrease of bone in the edentate group was associated with a lower stiffness and strength (about 22% and 28%, respectively). The ultimate strain, however, did not differ between the two groups. Both groups had similar mechanical anisotropy; in axial loading the bone was stiffer and stronger than in transverse loading. CONCLUSIONS: Reduced mechanical load had affected the density and herewith the mechanical properties of condylar cancellous bone, but not its anisotropy. RELEVANCE: The change in material properties of the cancellous bone after loss of teeth indicate that the mandibular condyle is sensitive for changes in its mechanical environment. Therefore, changes in mechanical loading of the condyle have to be accounted for in surgical procedures of the mandible.
The effects of estrogen deficiency on the mandible have been indicated; however, there have been only a few reports on the mandibular condyle. To clarify the region-specific changes of condyles following estrogen deficiency, we histomorphometrically studied the anterior and posterior regions of condyles in sham-operated (Sham) and ovariectomized (Ovx) female Fischer rats, since it has been reported that rat occlusal force loads mainly onto the anterior part of the condyle. The anterior and posterior regions of condyles showed significantly different bone dynamics. The bone volume in the anterior region of the Sham group increased to 79.9% with aging, but that of the posterior region remained at ca. 60%. In the Ovx group, the bone volume of the posterior region significantly declined to 42.7% until 60 days post-ovariectomy, although no changes occurred in the anterior region. As compared with the Sham counterparts, both regions of the Ovx group showed high bone turnover and revealed significantly low bone volume at 60 days (p < 0.01). Regional differences between anterior and posterior regions were more emphasized in the Ovx than in the Sham group. The osteoclast number and amount of eroded surface in the Ovx were higher in the posterior than in the anterior region, with significance at 30 and/or 60 days (p < 0.05). The mineralized surface at 14 days and the bone formation rate at 60 days in the Ovx posterior region were significantly lower than those in the Ovx anterior region (p < 0.05). Consequently, a net bone loss occurred in the posterior region of the mandibular condyle in ovariectomized rats, owing to region specificity and estrogen deficiency.
Four cases of bilateral bifid mandibular condyles are reported. A review of the literature showed that only four cases have been reported previously as incidental findings patients, while another four cases have been detected in post mortem material. Due to the minimal symptomatology, the diagnosis of a bifid condyle usually rests on radiological rather than clinical evidence.
An unusual case of adenocarcinoma of the prostate metastatic to the mandibular condyle that presented clinically as a parotid tumor is reported. Standard radiologic studies may be misleading in such cases, and a high index of suspicion is required for atypical masses in the parotid region.
This is the first report of double contour formation in the human mandibular condyle that includes both radiographic and histologic confirmation. Panoramic radiographs showed an additional cortical layer formation on the posterior of the condyle during follow-up after displacement of the condyle. Two cortical layers on the posterior portion of the condyle were demonstrated on the histologic specimen. The outer layer consisted of a few lamellated bone layers and included many osteocytes. However, minimal fibroconnective tissue was seen, and there was no cartilage layer. We concluded that the double contour formation was not caused by endochondral ossification but by periosteal bone formation.
Chondroblastoma is a highly destructive tumor, derived from immature cartilage cells, typically occurring in epiphyses of the long bones of adolescents and young adults. Those occurring in the temporal bone and TMJ area are likely to mimic TMJ symptoms. This report describes a unique case in which a chondroblastoma resulted in extensive destruction of the temporal bone, temporomandibular joint, mandibular condyle, and cranial base, including gross intracranial and extracranial involvement. With appropriate surgical management, the outcome for patients with chondroblastoma of the temporomandibular region is quite favorable. This case brings the total reported chondroblastomas to 59 in the temporal bone and eight in the mandibular condyle as of the date of submission of this article for publication.
The first case of osteoblastoma of the mandibular condyle is reported. The clinical, radiographic and histologic features of this benign neoplasm are described and the differential diagnosis is discussed.
The present paper reports alterations in osteogenesis recorded in mandibular condyles 3-18 days after the removal of marrow tissue from tibial bones. Computerized histomorphometric evaluation of undecalcified condyles revealed a considerable increase in the thickness of condylar cartilage, in particular, the zone of provisional calcification. Measurements of the subcartilaginous trabecular bone suggested an increase in the number of osteoblasts and in their activity. The systemic enhancement of osteogenesis may be initiated by circulating factors released at the affected limb during regeneration of the marrow.
The purpose of this study was to determine the degree of bony asymmetry between the right (R) and left (L) mandibular condyles and rami. On 25 dry skulls, condylar height, breadth and length, as well as ramus height and breadth were assessed. On each skull the average of the three measurements on the right and left sides, respectively, were calculated with the corresponding reference points being redetermined for each measurement. The raw absolute differences magnitude of R - L as well as the relative absolute differences magnitude of R - L/R + L were computed. The relative absolute differences showed that asymmetries were of similar magnitude (between 1.20% and 2.58%) for all variables except for condylar height (11.06%). After taking three additional measurements with reference points chosen only once, the intra-individual measurement error, consisting of reproducibility of the reference points and accuracy in measuring the distance between the chosen points, was assessed with the help of a statistical variance component technique. Estimates of the 95% range of the absolute differences were computed. Between 60% and 88% of the measured differences were outside the predicted 95% range, thus much too large to be explained by random measurement error; hence, they were due to real individual asymmetries. We concluded that asymmetries of mandibular condyles and rami are part of the biologic variation of humans. It still remains unclear, however, when such asymmetries should be considered "unphysiological."
The aim of the current study was to evaluate the effects of functional treatment appliances, a U-Bugel type I activator and a conventional activator, on the mandibular condyle considering the sagittal direction. Alterations in the growth direction and quantity of the condyle effects the ramal inclination and, consequently, the whole mandible. This situation is important when considering treatment prognosis and stability. The material consisted of pre- and post-treatment lateral cephalograms and hand-wrist films of 49 individuals having skeletal and dental Class II/div.1 malocclusions. Although the elimination of overjet and correction of Class II/div.1 anomalies was achieved, statistically significant changes were not observed in the sagittal direction of the mandibular condyle.
The clinical and radiological features of a patient with metastatic spread of testicular teratoma to both mandibular condyles are presented. It is suggested that in patients with known systemic malignancy, a local metastatic deposit should be considered as a possible cause of unexplained pain in the temporomandibular joints.