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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↗
PubMed1999

Neurilemmoma of the mandible.

Intraosseous neurilemmoma is rare, representing less than 1% of benign primary bone tumors. The site most commonly involved is the mandible. We report on a neurilemmoma of the mandible in a 30-year-old woman. A panoramic radiograph of the mandible showed a well-defined unilocular osteolytic lesion with a thin uniform sclerotic margin located in the body of the mandible. The CT scan confirmed a well-defined osteolytic lesion with thinning of the cortex of the body of the left side of the mandible. Histologically, the lesion was a moderately cellular neoplasm with distinct palisading and numerous Verocay bodies. Ultrastructurally, the cytoplasmic membranes were distinct and coated by amorphous bands of basal lamina. Complete excision was achieved by removing the tumor from the inferior alveolar nerve.

Adult↗
PubMed2002

Motor control of the mandible closer muscle in ants.

Despite their simple design, ant mandible movements cover a wide range of forces, velocities and amplitudes. The mandible is controlled by the mandible closer muscle, which is composed of two functionally distinct subpopulations of muscle fiber types: fast fibers (short sarcomeres) and slow ones (long sarcomeres). The entire muscle is controlled by 10-12 motor neurons, 4-5 of which exclusively supply fast muscle fibers. Slow muscle fibers comprise a posterior and an antero-lateral group, each of which is controlled by 1-2 motor neurons. In addition, 3-4 motor neurons control all muscle fibers together. Simultaneous recordings of muscle activity and mandible movement reveal that fast movements require rapid contractions of fast muscle fibers. Slow and subtle movements result from the activation of slow muscle fibers. Forceful movements are generated by simultaneous co-activation of all muscle fiber types. Retrograde tracing shows that most dendritic arborizations of the different sets of motor neurons share the same neuropil in the subesophageal ganglion. In addition, fast motor neurons and neurons supplying the lateral group of slow closer muscle fibers each invade specific parts of the neuropil that is not shared by the other motor neuron groups. Some bilateral overlap between the dendrites of left and right motor neurons exists, particularly in fast motor neurons. The results explain how a single muscle is able to control the different movement parameters required for the proper function of ant mandibles.

Journal Article↗
PubMed2006

[Chondroblastic osteosarcoma of the mandible: a case report with 14 years follow-up].

INTRODUCTION: Osteosarcoma, the second most frequent primary malignant bone tumor, is usually found in long bones: femur, tibia or humerus with only 6 to 7% of cases occurring in the jaws. Patients with osteosarcoma of the mandible usually complain of a swelling, which can be painful or not, accompanied by paresthesia of one of the trigeminal nerve branches in about 20% of cases. OBSERVATION: We report a case of chondroblastic osteosarcoma of the mandible affecting a 33-year-old woman with 14 years follow-up illustrating the difficulties of a rapid diagnosis. DISCUSSION: The prognosis of osteosarcoma of the mandible relies on its histological grade and the amount of time elapsing from diagnosis to treatment onset. The treatment of choice is radical surgery providing a 5-year survival rate up to 80%. The definitive surgical treatment is usually performed only after several interventions because operative-room pathology cannot be obtained due to the necessity of decalcification. In order to avoid multiple resections, an interim bridging with a reconstructive plate with a condylar head can be proposed before definitive graft reconstruction. The prognosis of osteosarcoma of the mandible is better than that of long bones. Chemotherapy or radiotherapy, which are very efficient for osteosarcoma in general, do not change the prognosis of osteosarcoma of the mandible.

Adult↗
PubMed2003

Surgical treatment of gunshot injuries to the mandible.

OBJECTIVES: Our goal was to review and identify risk factors for complications from treatment of mandible fractures due to gunshot wounds. Study design and setting We conducted a retrospective review of treatment outcomes in 90 patients with gunshot wounds to the mandible treated over a 10-year period at 2 tertiary care centers. RESULTS: Our series of 90 patients with mandibular injuries due to gunshot wounds included 68 patients who underwent surgical procedures on the mandible. There were 14 complications in this group. Complications were more common in patients whose mandibles were rigidly fixated; however, these patients' injuries were more severe. Complications were significantly increased in patients who lost a segment of mandible in the injury. CONCLUSIONS: Complications were related to severity of injury and independent of treatment modality. SIGNIFICANCE: The complication rate for patients with gunshot injuries can be very high, particularly if bone is missing. Stabilization of remaining mandibular segments with potentially multiple subsequent reconstructive procedures is often required to restore mandibular continuity in these patients.

Adolescent↗
PubMed2001

Osteoradionecrosis of the mandible. Comparison of the effects of external beam irradiation and brachytherapy.

OBJECTIVE: To compare the difference in location and severity of osteoradionecrosis (ORN) of the mandible following either external beam irradiation alone or combined with brachytherapy in the management of orofacial cancer. METHODS: CT was used to evaluate ORN in relation to the radiation source and field and the site of malignancy in 31 patients with orofacial carcinomas. Twenty-three patients received combined radiotherapy and brachytherapy and eight patients only external radiotherapy. The radiation dose distribution to the mandible was calculated retrospectively. RESULTS: In the combined radiotherapy group all patients had ORN of the lingual cortex, mostly adjacent to the position of previous iridium implants. Lingual defects were also found in the contralateral mandible in 35% of patients. Defects in the buccal cortex were seen in 30%. In the external radiotherapy group, ORN was found in both buccal and lingual cortices and 50% also in the contralateral mandible. When brachytherapy with iridium implants was used the dose to the buccal cortex was about one-third of that to the lingual cortex. There was no dose gradient between the cortices using external beam irradiation alone. CONCLUSIONS: Evidence of ORN was found in both groups of irradiation regimens. Thus, the entire irradiated mandible should be considered as a compromised tissue at risk of ORN.

Adult↗
PubMed2002

Radiotherapy for metastases to the mandible in children.

PURPOSE: We present a retrospective review of all children treated since 1979 at our institution with radiotherapy for symptomatic metastases that involve the mandible. PATIENTS AND METHODS: Nine children were treated with 1 or more courses of radiotherapy for symptomatic metastases that involve the mandible. Six children had a neuroblastoma, 1 had angiosarcoma of the liver, 1 had adenocarcinoma of the rectum, and 1 had peripheral primitive neuroectodermal tumor (Ewing's sarcoma) of the spine. In 3 children, the mandible was the first bone involved by metastases. Seven children were treated with short intensive courses of radiotherapy consisting of 1 to 3 fractions to a total dose of 400 to 1,200 cGy. One child received 2,400 cGy in 6 fractions, and another child received 3,000 cGy in 10 fractions. Three children were treated with second courses of radiotherapy at 1, 2, and 5 months, respectively, from the initial course of radiotherapy. All children had received chemotherapy. RESULTS: All children died of disseminated disease at 5 to 59 months from their initial diagnosis, 5 to 29 months from the detection of metastases to bone, and only 6 days to 17 months (median, 2 months) from the first treatment of metastases to the mandible. CONCLUSIONS: The outlook for children with metastases that involve the mandible is very poor, and we recommend short intensive courses of radiotherapy consisting of 1 to 3 treatments to total doses of 400 to 1,200 cGy for palliation of pain.

Adenocarcinoma↗
PubMed2000

Effect of preservation of the inferior and posterior borders on recurrence of ameloblastomas of the mandible.

OBJECTIVE: The purpose of this study was to evaluate the experience and results of using a rational radical conservative approach in the surgical treatment of mandibular ameloblastomas. STUDY DESIGN: A retrospective analysis of every patient with an ameloblastoma of the mandible treated in the Department of Oral Medicine and Oral Surgery at the Jordan University of Science and Technology between 1989 and 1999 was conducted. All were operated on by the author, who used a uniform surgical protocol in every case. All soft tissues in contact or overlying the lesion and a wide margin of cancellous bone related to the tumor were destroyed. The compact bone comprising the lower border of the mandible and the posterior border of the ascending ramus together with the nutrient periosteum attached to them were preserved, thus maintaining the continuity of the mandible and the facial contours. When teeth, soft tissues, or both were involved, they were destroyed. All patients were reviewed annually for a follow-up period of 3 to 10 years (mean, 6.5 years) by the same clinician. RESULTS: All ameloblastomas were located in the mandible; 21 were in the angle/molar region and the ascending ramus, and 2 cases were in the anterior region. There was no clinical or radiographic evidence of recurrence observed during the follow-up period. CONCLUSION: Ameloblastoma has a high rate of local recurrence if it is not adequately removed. The findings of this study to date suggest that the technique of rational radical conservative resection may have a place in the treatment of ameloblastoma of the mandible and is worthy of further trial.

Adolescent↗
PubMed2001

5196 mandible fractures among 4381 active duty army soldiers, 1980 to 1998.

OBJECTIVE: We present the frequencies of various types of mandibular fractures along with associated mechanisms and injuries. METHODS: Retrospective analysis of 5196 mandible fractures in 4381 patients extracted from the Total Army Injury and Health Outcomes Database (TAIHOD), a comprehensive database developed by the U.S. Army Research Institute of Environmental Medicine (USARIEM) that links population data to all hospitalizations among active duty army soldiers. The database is based on the ICD-9 CM coding system. RESULTS: We found the following frequencies for specific mandible fracture locations: angle 35.6%, symphysis 20.1%, subcondylar 14.2%, body 12.7%, condylar process 9.1%, ramus 4.5%, alveolar border 2.7%, and coronoid process 1%. The mechanisms of injury were separated into seven categories. Fighting accounts for 36.2%, automobile accidents for 18.6%, athletics for 13.6%, falls for 9.7%, motorcycle accidents for 3.1%, other land transport accidents for 3%, and miscellaneous causes for 15.8%. A few fracture locations appear to be associated with specific mechanisms. Of 82 alveolar border fractures with known mechanisms, 37% resulted from automobile accidents. Of 1094 angle fractures with known mechanisms, 48.6% resulted from fighting. Our data show that the majority of fractures were isolated to one location. Only one fracture was recorded for 70.6%, 29.2% have two fractures recorded, 0.2% have three or more fractures recorded. Associated injuries were common and include facial lacerations 1236 (28.2%), non-mandible facial bone fractures 733 (16.7%), intracranial injury 403(9.2%), internal injuries 229 (5.2%), fractures of the upper limb 295 (6.7%), fractures of the lower extremity 302 (6.9%), and cervical fractures 34 (0.8%). CONCLUSIONS: The mechanism of injury is important in determining the most likely resultant mandible fracture in the case of angle of mandible and alveolar ridge fractures. The clinician should maintain a high level of suspicion for associated injuries that occur more than one fourth of the time and even more frequently in motor vehicle accident victims. Associated intracranial injury is particularly important to rule out. Associated facial fractures, intracranial injury, internal injuries, and extremity injuries are all more common than cervical fractures.

Adolescent↗
PubMed2002

Distraction osteogenesis of costochondral bone grafts in the mandible.

Costochondral grafting for reconstruction of the Pruzansky type III mandible has given variable results. Lengthening of the rib graft by means of distraction had been advocated when subsequent growth of the grafted mandible is inadequate. This retrospective study reviews a series of patients with mandibular costochondral grafts who underwent subsequent distraction osteogenesis of the graft. A retrospective review identified two patient groups: group 1 consisted of individuals (n = 9) who underwent costochondral rib grafting of the mandible followed by distraction osteogenesis several months later at a rate of 1 mm/day. Group 2 consisted of patients with Pruzansky type II mandibles who had distraction osteogenesis without prior rib grafting (n = 9). The biomechanical parameters, orthodontic treatment regimens, and complications were examined versus patient age and quality of the rib graft. Distraction osteogenesis was successfully performed in six of the rib graft patients (group 1) and in all of the group 2 individuals. On the basis of the Haminishi scale, the computed tomographic scan appearance of the regenerate was classified as "standard or external" in six of the group 1 patients and as either "agenetic" or "pillar" (fibrous union) in the remaining three patients. In group 1, the average device was expanded 23 mm (range, 20 to 30 mm). Group 2 mandibular distraction results were all classified as either standard or external, and there was an average device expansion of 22.4 mm (range, 16 to 30 mm). The length of consolidation averaged 12.6 weeks in group 1, compared with 8.5 weeks in the traditional mandibular distraction patients (group 2). The mean shift of the dental midline to the contralateral side was 2.5 mm in group 1 versus 4.0 mm in group 2. Complex multiplanar and transport distractions were successfully performed on grafts of adequate bony volume. All four patients in group 1 with tracheostomies were successfully decannulated after consolidation. Rib graft distraction complications included pin tract infections in two patients, hardware failure with premature pin pullout in one patient, and evidence of fibrous nonunions in three young patients with single, diminutive rib grafts. In group 2, there were no distraction failures. Distraction osteogenesis can be successfully performed on costochondral rib grafts of the mandible; however, the complication rate is higher than in non-rib-graft patients. Performing the technique on older, more cooperative individuals seems to reduce this risk. In addition, placement of a double rib graft or an iliac bone graft of sufficient volume to create a neomandible with greater bone stock is an absolute requirement to decrease the risk of fibrous nonunion and provide a bone base of sufficient size for retention of the distraction device and manipulation of the regenerate.

Bone Transplantation↗
PubMed2004

Ballistic impact to the forehead, zygoma, and mandible: comparison of human and frangible dummy face biomechanics.

BACKGROUND: Currently, there is a greater use of nonlethal force in law enforcement and military operations. Because facial injuries have been observed, there is a need to understand the human response to ballistic impacts involving various regions of the face. This study aimed to establish blunt ballistic response corridors for high-speed, low-mass facial impacts to the forehead, zygoma, and mandible, and to determine how these responses compare with those of the frangible Hybrid III headform. Correlation of the human and dummy responses allows injury risk assessment for munitions used in the field. METHODS: Facial impacts to the forehead, zygoma, and mandible of six cadavers at 42 +/- 10 m/sec were conducted using a 25- to 35-g projectile 37 mm in diameter that was instrumented with an accelerometer to determine impact force. High-speed video analysis determined penetration of the projectile, and autopsy determined the facial fractures. Force and deflection were normalized for the 50% tile response, and corridors were determined for blunt ballistic impacts. Similar tests were conducted on the frangible face of the Hybrid III dummy. RESULTS: Peak normalized force of 3.5 +/- 0.9 kN on the forehead and 3.0 +/- 1.0 kN on the mandible did not result in fractures, whereas an impact force of 2.3 +/- 0.5 kN on the zygoma caused anterior maxilla fractures. The frangible Hybrid III face developed similar force levels, but with less penetration of the projectile. Its stiffness was 43% greater than that of the cadaver. CONCLUSIONS: Higher impact force can be tolerated on the forehead and mandible than on the zygoma. Normalized force-deflection and force-time corridors were established for the human response. The frangible Hybrid III face is an effective surrogate for assessing ballistic injury risks, but greater compliance would make it more biofidelic. Initial human tolerance levels of 6.0 kN for the forehead, 1.6 kN for the zygoma, and 1.9 kN for the mandible have been established for ballistic impacts to the face.

Aged↗
PubMed2006

A pilot study of quantitative assessment of mandible advancement using pressure-flow relationship during midazolam sedation.

It has been proposed that a titration of the mandibular positioner would be a promising method for predicting the outcome of nasal continuous positive airway pressure (CPAP) therapy. This study was carried out to test the hypothesis that mandible advancement could be evaluated by analysis of inspiratory flow limitation using a titration procedure. To explore its effect, we examined upper airway pressure-flow relationships using a titrated mandible positioner during midazolam sedation. Non-flow limited inspiration occurred when the mandible was advanced 7.1 +/- 1.2 mm from centric occlusion position. In the centric occlusion position (0 mm advancement), Pcrit was -1.9 +/- 2.9 cmH2O and Rua was 23.3 +/- 4.5 cmH2O L(-1) s(-1). In the eMAP position, Pcrit was -7.3 +/- 1.9 cmH2O and Rua was 27.8 +/- 3.3 cmH2O L(-1) s(-1). Essentially no CPAP was required to overcome flow limitation in eMAP position, whereas 3.7 +/- 2.2 cmH2O CPAP was required in centric occlusion position. We conclude that assessing inspiratory flow limitation using a titrated mandible positioner was effective for estimating individual-matched mandible positions.

Adult↗
PubMed1999

Optimizing force and velocity: mandible muscle fibre attachments in ants

To be able to perform swift and powerful movements, ant mandible closer muscles are composed of two subpopulations of muscle fibres: fast fibres for rapid actions and slow fibres for forceful biting. All these fibres attach to a sturdy and complex apodeme which conveys force into the mandible base. Fast muscle fibres attach directly to the apodeme. Slow fibres may attach directly or insert at individual thin filament processes of the apodeme which vary in length. Comparisons of different ant species suggest two basic principles underlying the design of mandible muscles. (1) Ants specialized for fast mandible movements generally feature long heads which contain long fast muscle fibres that attach to the apodeme at small angles. Their muscles comprise only a few filament-attached fibres and they maximize speed of action at the expense of force output. (2) Ants performing particularly forceful mandible movements, such as seed cracking, rely on many short parallel muscle fibres contained within a broad head capsule. Their slower muscles incorporate a large proportion of filament-attached fibres. Two simple models explain how the attachment angles are optimized with respect to force and velocity output and how filament-attached fibres help to generate the largest power output from the available head capsule volume.

Journal Article↗
PubMed1978

Morbid changes of the mandible in familial polyposis of the colon.

The study was made to ascertain whether the radiographs of the mandible of patients with familial polyposis of the colon show osteomas. Orthopantomography of the mandible was taken in 10 cases of familial polyposis of the colon and 6 cases of the unaffected family members. And radiographic and histological studies were performed in another autopsied case. As a result, radiographic studies revealed sclerotic masses of the mandible in 10 of the 11 cases. In some cases, the changes were also found in the maxilla. The number of sclerotic masses ranged from 2 to 11, and they were associated with odontomas in 2 cases and impacted teeth in one case. Two of the 6 unaffected family members were found to have one or two sclerotic masses. At autopsy of a case died of cancer of the sigmoid colon, a radiographic study of the excised mandible revealed 11 sclerotic masses measuring 5 mm in diameter each, as well as one impacted tooth. A bucco-lingual cross action through the mandible in the canine area revealed central osteomas. Histological examination showed the osteomas were composed primarily of mature, lamellar bony tissue.

Adolescent↗
PubMed1998

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst: delineation of surgical margins and reconstruction with bilateral rectus abdominis myocutaneous free flaps.

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst is reported. A 38-year-old man was admitted to the Tokai University Hospital due to postoperative infection of a recurrent odontogenic keratocyst of the left mandible. He had had a cystectomy for an odontogenic keratocyst 4 years ago. The lesion revealed bony destruction of the mandible with worm-eating shaped margins with extension to the facial skin. A biopsy specimen revealed squamous cell carcinoma. The mandible was resected with facial skin and the sublingual space was dissected to preserve the lingual nerve. The oral and the facial resections were reconstructed with a titanium plate and bilateral rectus abdominis myocutaneous free flaps. The plate was removed due to infection around the margins and readjustment of the flaps was conducted 5 months after the surgery. He has not had a local relapse, metastasis, or incisional hernia for 8 months following surgery. Good occlusion has been attained by the residual mandible, and he is able to eat without any problems.

Adult↗
PubMed1998

Stress distribution in the mandible with unilateral condylar fracture.

OBJECTIVE: The purpose of this study was to investigate the influence of unilateral condylar neck fracture upon the stress distribution in the mandible and the temporomandibular joint (TMJ) to realize primarily the biomechanical mechanism of the temporomandibular joint disorders (TMD) caused by TMJ injury. METHODS: The character of stress distribution in the mandible of a normal human and a patient with TMD induced by unilateral condylar neck fracture followed by malpositioned healing was analyzed quantitatively and compared during centric occlusion by combining spiral computed tomography scanning technology with the three-dimensional finite element method. RESULTS: The patient with unilateral condylar neck fracture followed by malpositioned healing had unbalanced stress distribution in the mandible, such as differing nature and value of stress. The stress in the fractured side was higher than in the nonfractured side, in which the condyle was more evident. The maximum principal stress and minimum principal stress of each region in the fractured mandible were much higher than those in a normal mandible. Stress quality also differed. CONCLUSIONS: The abnormal stress changes after unilateral condylar neck fracture with malpositioned healing may be related to the effect of condylar shape change on masticatory muscle function and occlusion. TMJ injury not only damaged the condylar structure, but also compromised its biomechanic environment. It is preliminarily thought that unbalanced stress distribution, evidently increased stress, and varied stress character are biomechanic mechanisms of TMD. Condylar dislocated fracture should be treated promptly and properly to maintain the proper prognostic stress distribution.

Adult↗
PubMedDate not supplied

[The phantom mandible].

The authors report a case of "phanton mandible" (phantom bone, disappearing bone, massive osteolysis affecting the mandible), describing the clinical colrse and radiological appearance of the condition. From a diagnosis of non-specific osteitis of the premolar region, they observed their patient until there was virtually total disappearance of the osseous structure of the mandible. Studying the world literature, they have collected 11 cases of the disorder involving the mandible, and, in some cases, the facial skeleton. They distinguish this condition from senile atrophy of the mandible and, after histological study, feel that it is not possible to classify this case in the context of Gorham's disease: in fact, haemangiomatosis was proved histologically in only three of the eleven cases described in the facial area.

Bone Diseases↗
PubMed1999

[Diagnosis and treatment of central hemangioma of mandible].

OBJECTIVE: To investigate methods of diagnosis and treatment of hemangiomas of the mandible. METHODS: Nineteen cases of central hemangioma of the mandible treated in our department from 1971 to 1997 were studied retrospectively. Fourteen patients received surgical treatment in which ten patients had received complete curettage of the lesion and the other four had received part resection of the mandible. RESULTS: The most common signs and symptoms of this lesion were hypermobility of teeth and episodes of spontaneous hemorrhage from the surrounding gingival sulcus. Selective angiography was significant in the diagnosis of this lesion. Fourteen patients received surgical treatment and thirteen lesions were removed completely, except that one died of massive bleeding at the operation and DIC on the next day. CONCLUSION: Selective angiography is useful to diagnosis the central hemangioma of mandible, and the complete curettage of the hemangiomas in the body of mandible is the most appropriate operation for children. At the same time, ligature of the inferior alveolar artery can reduce the risk of bleeding during operation.

Adolescent↗