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PubMed2001

The expression of osteopontin with condylar remodeling in growing rats.

It is suggested that osteopontin may promote osteoclast binding to resorptive sites by interacting with the alphavbeta3 receptor on osteoclasts. However, the role of osteopontin in functional remodeling of bony structures remains unclear. The present study was conducted to examine the distribution of osteopontin on the condyle and explore the role in condylar remodeling in growing rats using an immunohistochemical method. Twenty Wistar strain male rats aged 7, 14, 28 and 56 days were used. In 7- and 14-day-old rats, no immunoreaction to osteopontin was detected in the cartilage cells. In 28-day-old rats initiating mastication, the thickness of condylar cartilage was decreased abruptly as compared to the younger rats. High immunoreaction to osteopontin was found in the cytoplasm of hypertrophic chondrocytes and on the trabecular bone surfaces of primary spongiosa adjacent to the osteoclasts or chondroclasts. The immunoreactions to osteopontin in the cytoplasm of hypertrophic chondrocytes were less in 56-day-old rats than in 28-day-old rats. It is shown that the alteration in mechanical loading on the mandibular condyle due to functional changes from weaning to mastication correlates with the localization of osteopontin in growing rats. Furthermore, it is suggested that osteopontin may stimulate osteoclastic resorption of calcified matrix by mediating the attachment of osteoclasts and/or chondroclasts during growth-related functional remodeling of the condyle.

Journal Article↗
PubMed2001

[Traumatic temporomandibular joint injuries].

Injuries of the temporomandibular joint are mostly due to injuries or fractures of the mandibular condyle. Fractures of the skull base involving the temporomandibular joint are rare. Classification of fractures refers to their anatomical positions and the presence or absence of a luxation. Further, it is important whether the fracture is intra- or extra-capsular. The primary imaging method should be orthopantomography. As for therapy planning, especially surgery, also evaluation of soft tissue is necessary, computed tomography is the imaging method of choice. For diagnosis of complications or internal derangement of the temporomandibular joint, magnetic resonance imaging is to be recommended.

Humans↗
PubMed2002

Morphologic changes in the TMJ following splint wear.

Intraoral splints are a commonly used dental treatment for a variety of conditions. Because such splints alter the condyle-disc-fossa relationship, they probably change the loading status of the temporomandibular joint (TMJ), including the TMJ disc. Collagen, a major constituent of the disc, acts to resist tensile loading, and it is presumed that the fiber orientations of the individual disc bands reflect their functional loading. Therefore, the purpose of this study was to examine effects of intraoral splint wear on TMJ morphology in general, and collagen orientation of the intra-articular disc in particular. Young adult, female miniature pigs were divided into three groups: open-bite splint, protrusive-bite splint, and unsplinted control. Splints were worn for 2 months, after which the TMJ discs were harvested for histological examination and stereological analysis, and the skulls were cleaned. Although the splints had no effect on skull dimensions, changes were seen in the TMJs. The discs of the protrusively-splinted group showed an increased thickness of the posterior band (P < 0.015) and minor changes in collagen orientation of the anterior band. The most striking change was the presence of a degenerative osseous defect on the medial side of the mandibular condyle in half of the splinted animals. These results indicate that prolonged splint wear can induce remodeling and even injury of TMJ tissues.

Animals↗
PubMed1994

Primary mandibular reconstruction with bridging plates.

25 cases in which the mandible was resected and reconstructed using a reconstruction plate (AO titanium reconstruction system and Leibinger titanium reconstruction system) are presented. 16 patients suffered from oral carcinoma, 7 presented with odontogenic tumours and 2 had chronic osteomyelitis of the mandible. The mean age was 54.2 years, the male to female ratio was 2.6:1. 3 patients had a reconstruction plate for mandibular resection without continuity defect (marginal resection), in all the other patients the reconstruction plate bridged a mandibular resection with a continuity defect: 13 were located in the body, body-angle or ascending ramus with preservation of the mandibular condyle; 4 hemimandibulectomies with disarticulation of the TMJ; and 5 involved the anterior arch, crossing the midline. 12 patients received radiotherapy (3 pre-operatively). Only 3 patients with significant local side effects needed the treatment to be stopped for a period of time. There was no perioperative mortality. Only one plate was removed. Although minor complications were noted in 11 patients, the general improvement in the functional and cosmetic balance of the patients when compared with patients in whom no plate was used, justifies the use of this reconstruction system, in our opinion.

Adolescent↗
PubMed2002

Combined surgical therapy of temporomandibular joint ankylosis and secondary deformity using intraoral distraction.

Temporomandibular joint (TMJ) ankylosis is a pathological process caused by damage of the mandibular condyle. When this event takes place in subjects during the developmental age, it results in an alteration of the entire maxillofacial complex. Therefore, surgical methods able to remove the temporomandibular ankylosis also include necessary operations to correct the secondary maxillofacial deformity. The distraction osteogenesis has induced our center to modify the surgical protocol for the therapy of patients who have developed TMJ ankylosis and secondary maxillomandibular deformity. We have treated four patients with monolateral ankylosis of the TMJ and serious deformities of the maxillomandibular complex secondary to functional limitation. During the same operation, arthroplasty was performed with the removal of the ankylotic block and the interposition of a temporal muscle flap in the new articular space; an intraoral osteodistractor was also positioned to lengthen the mandible. All patients showed recovery of the eurhythmy of the face and good re-establishment of the symmetry. An average 12-month follow-up showed the average opening of the mouth to be at least 35 mm. The combination of TMJ arthroplasty and intraoral osteodistraction provides good functional and aesthetic results in patients affected by ankylosis who have developed secondary maxillofacial deformities.

Adolescent↗
PubMedDate not supplied

Endoscopically assisted repair of subcondylar fractures of the mandible: an evolving technique.

OBJECTIVE: To review one surgeon's experience with the endoscopic approach to assist with reduction and rigid fixation of subcondylar fractures of the mandible. DESIGN: Chart review of all cases in which endoscopic techniques were used to assist with the reduction and, when possible, repair of these fractures. The numbers of fractures approached, successfully repaired with the use of plates and screws, and not successfully plated with this approach were documented. SETTING: All surgeries were performed in the operating room at a university hospital. PATIENTS: All patients who underwent endoscopic exploration of a single or bilateral subcondylar fractures of the mandible were included. Seventeen explorations were carried out in 12 patients (age range, 16-39 years). Associated mandibular and other facial fractures were noted. INTERVENTIONS: Endoscopic exploration via a transoral approach. A secondary port in the submandibular region was made in 13 of 17 fracture explorations, and this second port was used primarily for the application of downward traction on the angle of the mandible. Plates were introduced transorally, while screws were placed through a transbuccal trochar. MAIN OUTCOME MEASURE: Success was judged by the successful reduction of the fracture and application of a rigid fixation plate by means of the limited, endoscopically assisted approach, a measure of the ability to accomplish the procedure, not an evaluation of functional results. (With these criteria, 9 of 10 successes had normal function at last follow-up, as did the 10th after revision.) RESULTS: Rigid plate fixation was completed endoscopically for 10 fractures, and 2 were plated after conversion to a full open approach. Four were reduced but could not be plated, and in 1 exploration, a bent plate was removed, but a new plate was not applied. Nine of the 10 fractures plated endoscopically resulted in normal occlusion and function. In the 10th case, a persistent malocclusion necessitated reexploration and refixation, resulting in a successful functional outcome with normal occlusion. CONCLUSION: The endoscopically assisted approach for the repair of subcondylar fractures of the mandible is a feasible but challenging technique.

Adolescent↗
PubMed1979

Infratemporal fossa approach to lesions in the temporal bone and base of the skull.

An infratemporal fossa approach for extensive tumors of the temporal bone, clivus, and parasellar and parasphenoid regions features permanent anterior transposition of the facial nerve, resection of the mandibular condyle, and mobilization of the zygoma and lateral orbital rim. Obliteration of the pneumatic spaces of the temporal bone with permanent occlusion of the Eustachian tube and blindsack closure of the external auditory canal avoids the danger of postoperative infection and leads to primary wound healing in the shortest time. Three cases demonstrate selective utilization of the infratemporal fossa approach. Short-term results and complications were observed in 51 patients.

Adult↗
PubMed1991

Mandibular fractures in the pediatric patient.

Seventy-three patients were admitted to the Children's Hospital of Philadelphia (Pa) between January 1979 and June 1989 with a diagnosis of mandibular fracture. Data were obtained through a retrospective review of these cases. The cases were divided into three age groups that reflected the developing structure of the mandible and the maturation of the dentition. A trend toward a greater number of fractures and a predominance of males is shown with increasing age. Child abuse is a relatively frequent cause of fractures throughout all groups. Associated injuries are more common in young children, except in cases where abuse has been documented. The high osteogenic potential of the pediatric mandible allowed conservative management to be successful in 25% of younger patients and was responsible for a low complication rate overall.

Accidents, Traffic↗
PubMed1994

Intraoral monocortical miniplating of mandible fractures.

OBJECTIVE: Intraoral monocortical miniplate fixation of mandibular fractures provides simultaneous visualization of the fracture and occlusal relation, while almost eliminating external incisions and potential compromise of the marginal mandibular nerve. We sought to analyze the outcome of our patients treated with this technique and compare this with literature standards for mandible fracture repair outcome. DESIGN: A retrospective analysis of outcomes for a case series. SETTING: All treatment performed in inner city, level 1 or 2 trauma rated, teaching hospitals. PATIENTS: During a 5-year period, 287 patients with 499 mandible fractures were treated with intraoral miniplates. Follow-up criteria was available for a retrospective analysis of 246 patients with 432 fractures of the mandible. INTERVENTION: Intraoral monocortical plating techniques were used to treat 313 of these 432 mandibular fractures. MAIN OUTCOME MEASURES: All complications of bone union, occlusion, wound infection, and dehiscence were graded and tabulated. RESULTS: On analysis of the miniplated fractures, 1.2% of the patients had delayed union, 0.4% had non-union, 6.5% had postoperative wound infection develop, and 4.1% had varying degrees of malunion. Complication rates are comparable with most reported studies of bicortical and monocortical plating of mandible fractures. CONCLUSIONS: Monocortical miniplate fixation is a reliable method of providing rigid fixation. It offers a reasonable alternative to bicortical plating in most mandible fractures.

Bone Plates↗
PubMed1995

Traditional methods vs rigid internal fixation of mandible fractures.

OBJECTIVE: To compare traditional methods (ie, intermaxillary fixation with interosseous wiring or external fixation) with newer techniques (ie, plating, use of lag screws) of open reduction and fixation of mandible fractures. DESIGN: Retrospective analysis of data from medical records. SETTING: Academic urban medical center. PATIENTS: Nonrandomized sample of 356 patients admitted to the hospital for treatment of mandible fractures from 1987 through 1991; 155 patients treated with open reduction and fixation were studied. INTERVENTIONS: Sixty-nine patients were treated with interosseous wire fixation or external fixation, 86 patients with rigid internal fixation. MAIN OUTCOME MEASURES: Presence of infection, nerve impairment, nonunion, malunion, operative time, and follow-up. RESULTS: No significant difference was noted between the two groups for sex, treating service, delay in presentation, antibiotic coverage, mechanism of injury, or type of fracture. The incidence of infection, nerve injury, and unavailability for follow-up were greater in patients treated by the newer techniques. Overall expense and operative time were greater in the group treated with plates and lag screws. CONCLUSIONS: We advocate traditional techniques for patients with mandible fractures requiring open reduction and fixation.

Bone Plates↗
PubMed1996

Influence of antineoplastic therapy on function of the masticatory system, tooth development, and cariogenic status: a case report.

Antineoplastic therapy causes developmental disturbances in the dental enamel and root if children are treated during tooth development. Increased caries activity has also been reported. The effect of anticancer therapy on the function of the masticatory system (i.e. jaws, dentition, masticatory muscles) is not well known. A case report of a 9-year-old girl with right auricular rhabdomyosarcoma is presented. She received irradiation of 50 Gy to the right auricular area and chemotherapy. A year and a half after cessation of cancer therapy, she was disease free and the clinical stomatognathic examination combined with electromyogram (EMG) registration of the masseter and temporal muscles and magnetic resonance imaging (MRI) examination of the temporomandibular joints (TMJ) revealed a strongly restricted mouth opening capacity, painful right TMJ, and flattened head of the right mandibular condyle. Muscle atrophy in the right masseter muscle was clearly visible but EMG activities of the masseter and temporal muscles, however, were higher on the right than on the left. More severe developmental defects, and worse gingival and cariological health were observed on the right side than on the left side. She developed 12 carious lesions and all the lesions were on the right maxilla or mandible or on anterior teeth. The left side was not affected. Intensive prophylactic dental care after cancer treatment is important in order to prevent caries and gingival inflammation. Stomatognathic treatment (i.e. management of occlusal and dysfunctional problems) may improve the mouth opening capacity and relieve pain.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Craniofacial abnormalities in mice carrying a dominant interference mutation in type X collagen.

Type X collagen is a short, non-fibril forming collagen restricted to hypertrophic cartilage, and has been hypothesized to play a role in endochondral ossification. The purpose of the study was to investigate the consequences resulting from the interference of type X collagen function on the growth and development of the craniofacial skeleton through analysis of transgenic mice with a dominant interference mutation for type X collagen. The craniofacial tissues of 21-day-old transgenic mice were examined by: cephalometric and radiographic densitometry analyses, conventional histology, and immunohistochemistry using antibodies specific for either endogenous mouse type X collagen or the transgene product. Genotypically positive mutant mice showed moderate but statistically significant craniofacial skeletal abnormalities, including the underdevelopment of the chondrocranium and mandible, but no cleft palate. Mean radiographic optical densities of the mutant condylar cartilage and the subchondylar areas were 32% less than the corresponding areas of normal mandibles, while mean radiographic optical density measured at the incisor tooth point remained constant. Histologically, transgene-positive mice revealed compressed hypertrophic cartilage zones and reduced trabeculae in both the mandibular condyle and the synchondroses of the chondrocranium. In the normal condyle, mouse type X collagen was localized by the monospecific antibody against a synthetic rat type X collagen NC1 peptide throughout the hypertrophic cartilage layer; in the mutant condyle, immunoreactivity to endogenous type X collagen was only seen sporadically. The truncated type X collagen transgene product, identified with the monoclonal antibody against an epitope within the chick type X collagen NC2 domain, persisted in the lower hypertrophic cartilage layer and the primary spongiosa, rather than being removed by subsequent endochondral ossification. The data suggested that the expression of the chick type X collagen transgene product was strongly associated with the craniofacial skeletal abnormalities that were distinct from other cartilage-related phenotypes.

Animals↗
PubMed2000

Increased in vivo levels of neurotransmitters to trigeminal motoneurons: effects on craniofacial bone and TMJ.

The results of chronic, in vivo delivery of excitatory and inhibitory neurotransmitter substances upon the craniofacial skeleton are of ongoing interest to clinician and basic scientist alike. Our purpose was to document and compare the effects of biodegradable glycine, glutamate, and thyrotropin-releasing hormone (TRH) microspheres upon the craniofacial skeleton and TMJ of actively growing rats. Glycine, glutamate, TRH, and blank microspheres were stereotactically implanted in proximity to motoneurons within the trigeminal motor nucleus in order to test the following null hypotheses: (1) neurotransmitter microspheres implanted near trigeminal motoneurons of growing rats have no significant effect on the craniofacial skeleton and temporomandibular joints of implanted animals, and (2) there are no significant differences between the relative effects of glutamate, TRH (excitatory to trigeminal motoneurons), and glycine (inhibitory to trigeminal motoneurons) implants upon the craniofacial skeleton and temporomandibular joint. Fifty male Sprague-Dawley rats underwent stereotactic neurosurgery at 35 days; five rats each were killed at 14 and 21 days postoperative for data collection and comparison between glycine-, glutamate-, TRH-, blank-microsphere, and sham-surgery rats. Glycine rats had significantly (P < or = 0.05, 0. 01) smaller implant-side cranial dimensions and mandibular condyles, all glycine rats showed increased gracility of implant-side bones, and deviation of their facial skeleton away from the implant-side; this was in contrast to the generally larger implant-side bony structures in both glutamate and TRH rats. The two null hypotheses were both rejected. Due to their inhibitory and excitatory effects upon trigeminal motoneurons, masticatory muscles, and their neuromuscular generation of biomechanical forces that affect bone, the neurotransmitter substances glycine, glutamate, and TRH appear to play an important role in the growth and development of the mammalian craniofacial skeleton and TMJ.

Animals↗
PubMed1998

Balancing function of the masticatory muscles during incisal biting in two murid rodents, Apodemus speciosus and Clethrionomys rufocanus.

The functional significance of masticatory muscle direction was estimated using a mechanical model in two murid rodents: the Japanese field mouse (Apodemus speciosus) and the gray red-backed vole (Clethrionomys rufocanus). Theoretical analyses of the data suggest that a balancing mechanism among the muscle forces occurs during incisal power stroke. The activation of the large deep masseter in both murids results in marked tensile separation of two hemimandibles at the flexible mandibular symphysis. Activation of the internal pterygoid decreases this large tensile force at the symphysis more efficiently than other muscles. The lines of action of the deep masseter and internal pterygoid are aligned to produce such a balancing function in both species studied here. The resultant force generated by the deep masseter on both sides is opposite in direction to the reaction force at the lower incisor tip. Therefore, the large deep masseter forms an effective mandibular support mechanism when the reaction forces during biting push the mandible downward. Because of the area of insertion and the line of action, the posterior temporalis appears to have an important role in stabilizing the position of the mandibular condyle in the glenoid fossa during incisal biting.

Animals↗