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[Experimental study on allogeneic mandible transplantation combined with basic fibroblast growth factor]

OBJECTIVE: To study the effect of basic fibroblast growth factor(b-FGF) on revascularization and bone remodeling of allogeneic mandible transplantation in repair of mandible defects in rabbits. METHODS: The mandible defects of 20 adult rabbits were created in both sides. The defects on the left side were implanted with allogeneic bone and local administration of b-FGF; the defects on the right side were only repaired with allogeneic bone as control group. At 1, 3 months after operation, the revascularization and bone remodeling were observed by ink-gelation vascular perfusion-transparency and histological examination. RESULTS: The allogeneic bone and b-FGF group had more marked vascularization and more quick and complete bone formation than control group. CONCLUSION: b-FGF can improve revascularization and bone formation after allogeneic mandible transplantation; allogeneic bone combined with b-FGF is a promising bone substitute in clinical uses.

Journal Article↗

Fractures of the rostral portion of the mandible and maxilla in horses: 89 cases (1979-1997).

OBJECTIVE: To compare fracture locations, repair methods, complications, and outcomes of horses with fractures of the rostral portions of the mandible and maxilla. DESIGN: Retrospective study. ANIMALS: 89 horses with fractures of the rostral portions of the mandible and maxilla. PROCEDURE: Medical records and radiographs were reviewed. Fractures were categorized by fracture location and stability. Postoperative complications and long-term outcome were determined by clinical examination and telephone interviews with horse owners. RESULTS: 4 fracture types were recognized. Fractures involving just the alveolar plate (33%) and those involving the alveolar plate and the body of the bone (32%) were most common and were often repaired by interdental wiring. Unilateral fractures of the mandible (11%) were managed without surgery if stable. Unstable fractures were repaired with wires, a U-shaped bar (U-bar), or a bone plate. Bilateral fractures (24%) were often repaired with orthopedic wires in foals or with a U-bar, acrylic splint, wires, or bone plate in adult horses. In 2 horses, bilateral fractures were managed conservatively. Short-term complications developed in 24 of 89 (27%) horses. Soft tissue infections and wire loosening or failure were the most common short-term and long-term complications. Wire replacement was not required in any horses after release from hospital. Persistent draining tracts were most often associated with bone sequestration. Long-term functional and cosmetic outcomes were favorable for all fracture types and repair methods. CLINICAL IMPLICATIONS: Although complications in horses with fractures of the mandible and maxilla are common, long-term prognoses for functional and cosmetic outcome are favorable.

Animals↗

Effect of recombinant human basic fibroblast growth factor on angiogenesis during mandible fracture healing in rabbits.

OBJECTIVE: To investigate the effect of recombinant human basic fibroblast growth factor (rhbFGF) on angiogenesis during mandible fracture healing in rabbit. METHODS: Fifty adult white rabbits were used for animal model and randomly divided into a control group (25 rabbits) and an experimental group (25 rabbits). The membranous complex of rhbFGF and bovine type I collagen was prepared and implanted into the rabbit mandible fracture site under periosteum. The animals were sacrificed on 7, 14, 28, 56 and 84 days respectively after operation and the whole mandibles were harvested. The expression of factor VIII related antigen (F8-RA) in callus was examined with immunohistochemical staining. RESULTS: The amounts of microvascular formation in calluses in the rhbFGF-treating group on days 7, 14, 28 and 56 were more than those of the control group (P<0.01). CONCLUSIONS: The results indicated that rhbFGF could stimulate microvascular formation during mandible fracture healing in rabbits.

Animals↗

[Effects on the growth and development of mandible with different treatment following condylar neck fracture in rat]

The condylar necks of young rats are fractured on this experiment.Fractures are treated with nonfixation and fixation,The growth and development of mandible can be interrupted in two groups,with a relatively small in condylar head,a relatively thick in condylar neck.A coronoid and a mandible length are relatively short.But the growth and development of mandible almost are completed,bilateral mandibles are almost symmetry except for ramus.The difference are not found in between two groups.The results of this study implied that young condylar neck fracture may be treated by conservation.

Journal Article↗

Contribution to the radiological study of the eosinophilic granuloma of the mandible (unifocal granuloma due to Langerhans' cell histiocytosis).

PURPOSE: The radiological diagnosis of osteolytic lesions of the mandible still constitutes a challenge in some pathological conditions in which the clinical data and the case history are relatively uniform and the radiological picture is lacking in any characteristics. MATERIALS AND METHODS: We reviewed the conventional radiograms of six cases of Langerhans' cell histiocytosis (LCH) of the mandible examined over the last ten years. The X-ray examinations were performed in the lateral-oblique projection to allow a view of the horizontal portion of the mandible almost completely free of overlapping images of other bone structures. RESULTS: We identified a series of radiological patterns for these reticulo-endotheliopathies capable of causing granuloma formed by polynuclear eosinophils, plasma cells, lymphocytes, and large mononuclear macrophages with granulopexic and phagocytic activity that proliferate in the bone tissue and can be identified as the Langerhans' cells of skin, mucosa, periodontal cavities and bone marrow. The granulomatous tissue penetrates the affected organ elements and, in its spread, it compresses, atrophies, and destroys the damaged tissue, replacing it. The alterations produced by Langerhans' cell histiocytic granuloma are most common in the skeletal system affecting, in order of frequency, the skull, the long bones of the limbs, the foot, the ribs and the spine. The oral mucosa is rarely involved. CONCLUSIONS: The radiological investigation of unifocal Langerhans' cell histiocytic granuloma of the mandible is essential in the study of perimandibular swelling, although diagnosis is based on biopsy alone. In addition to digital or conventional radiography, other useful examinations are bone scintigraphy, Colour Doppler US, MR and CT, which enables a correct localisation necessary for planning the biopsy and treatment.

Adult↗

Primary de novo intraosseous carcinoma of the mandible--report of a case and review of literature.

Primary intraosseous carcinoma (PIOC) is a rare malignant odontogenic neoplasm defined as squamous cell carcinoma arising within thejaws, having no initial connection with the oral mucosa and presumably developing from the residues of the odontogenic eptihelium. A 37yr old male patient reported with the complaint of pain and swelling in the right mandible and inability to open his mouth for the past six months. Examination revealed an expansile mass that involved the right mandible and extended from the 1st premolar region to the right angle of the mandible. The alveolar ridge was markedly expanded and was covered with intact, normal appearing mucosa. Radiographic examination revealed an ill-defined radiolucent area in the right body of the mandible, which extended to the lower border. Histopathologic examination revealed a well differentiated keratinizing squamous cell carcinoma. PIOC has no specific histopathologic features and can be definitively diagnosed only upon fulfillment of various criteria. These criteria were followed in our case and reported here for its rarity.

Adult↗

[Screw-wire combination technique in the reconstruction of anterior mandible fractures].

BACKGROUND: Fractures of the mandible are among frequently seen facial injuries and their reconstruction requires unique procedures. The purpose of this study is to demonstrate the efficacy of screw-wire combination osteosynthesis technique in the treatment of simple and displaced, symphisis and parasymphisis mandible fractures. METHODS: In our clinic 9 simple and displaced, symphysis and parasymphysis fractures of mandible were treated with screw-wire combination osteosynthesis technique. By intraoral approach 4 screws were applied to both sides of the fracture site 5 mm away from either side placed at superior (n = 2) and inferior (n = 2) localizations. Lower and upper wires were placed bicortically, and unicortically respectively . In order to surround them with wire, the screws were not fully tightened. After surrounding the screws, the wires were tightened in a manner that would properly face the fracture sites mutually. Intermaxillary fixation was applied for 7 to 10 days in all patients. RESULTS: During follow up period we did not encounter infection, malunion, nonunion, delayed union and patient discomfort necessitating extirpation of the materials fixed. CONCLUSION: We think that screw-wire combination technique is an easy and effective method with low cost and fast healing especially in reconstruction of anterior mandible fractures.

Bone Screws↗

Nonsurgical and nonextraction treatment of a skeletal class III adult patient with severe prognathic mandible.

AIM: A patient with a skeletal Class III malocclusion, prognathic mandible, anterior open bite, large tongue, and temporomandibular disorders is presented. Treatment objectives included establishing a stable occlusion with normal respiration, eliminating temporomandibular disorder symptoms, and improving facial esthetics through nonextraction and nonsurgical treatment by creating a favorable perioral environment, restoring the harmony to the tongue and perioral environment, improving masticatory muscle function, and creating adequate tongue space for establishment of normal respiration. SUBJECT AND METHODS: The patient was a Japanese adult male, who had previously been advised to have orthognathic surgery, with tongue-size reduction. An expansion plate was used to expand the maxillary dentoalveolar arch. Distalization of the mandibular arch was achieved by reduced excessive posterior vertical dimension, through uprighting and intruding the mandibular posterior teeth and rotating the mandible slightly counter-clockwise. The height of the maxillary alveolar process and the vertical height of symphysis were increased slightly. The functional occlusal plane was reconstructed by uprighting and intruding the posterior teeth with a full-bracket appliance, combined with a maxillary expansion plate, with short Class III and vertical elastics in the anterior area. Myofunctional therapy involved sugarless chewing gum exercises. RESULTS: The excessive posterior vertical occlusal dimension was reduced slightly, creating a small clearance between the posterior maxilla and mandible. At the same time, the interferences in the posterior area were eliminated by the expansion of the maxillary dentoalveolar arch. As a result, the laterally displaced mandible moved to a more favorable jaw relationship, with distalization of the mandibular arch. The functional occlusal plane was reconstructed and an almost-normal overjet and overbite were created. Adequate tongue space for normal respiration was established during the early stage of treatment, by 7 months. A stable occlusion, with adequate posterior support and anterior guidance, was established and maintained at more than 4 years posttreatment.

Adolescent↗

Implant prosthodontic rehabilitation of fibula free-flap reconstructed mandibles: a Memorial Sloan-Kettering Cancer Center review of prognostic factors and implant outcomes.

PURPOSE: This study aimed to estimate the cumulative survival rates (CSRs) of implants placed in reconstructed mandibles and to identify prognostic factors that may influence implant survival. MATERIALS AND METHODS: The charts of 24 patients (10 male, 14 female) who had undergone mandibular resection and reconstruction with fibula free-flaps treated with implant-supported prostheses from April 1986 through December 2001 were reviewed. Information on demographics, surgical characteristics, treatment modalities, dentition, implant parameters, prostheses, and hyperbaric oxygen therapy (HBO) was gathered. Kaplan-Meier survival estimates were generated for the 100 implants that satisfied the inclusion criteria. Multivariate Cox proportional hazards regression models accounting for correlated implants within subjects were developed to identify prognostic factors for implant survival. RESULTS: Ninteen implants had been placed in native mandible (3 in irradiated bone) and 81 in fibula bone flap. Six implants failed during the follow-up period (mean 51.7 months). The overall 5- and 10-year CSRs were 97.0% and 79.9%, respectively. In the univariate analysis, variables associated with implant survival were age, gender, chemotherapy, radiation therapy, HBO, irradiated bone, implant diameter, xerostomia, trismus, opposing dentition, and type of prosthesis. At 5 years, the CSR of implants in patients with HBO was 86.7%; HBO was statistically associated with an increased risk for implant failure (P = .005, hazard ratio = 19.79, 95% CI: 2.42 to 161.71). DISCUSSION: The CSR was lower when implants were placed in a previously irradiated mandible. There is still a lack of reliable clinical evidence to support the effectiveness of HBO in these patients. CONCLUSIONS: A high survival rate was demonstrated for implants placed in fibula free-flap reconstructed mandibles. The finding that HBO was a risk factor can probably be attributed to the small sample size; further study is needed in this patient population.

Adolescent↗

Reticulum cell sarcoma of the mandible: report of case.

A case of reticulum cell sarcoma of the mandible in a 77-year-old woman has been presented. The patient said that she experienced pain and numbness of the affected area (mandible and lip) for two months and then a small swelling appeared. The tumor was first seen in the soft tissues of the right side of the mandible, but radiographic findings in the bone allowed us to conclude that the tumor originated in the mandible, and spread to soft tissue.

Aged↗

Solitary intraosseous neurofibroma of the mandible: report of a case.

A case of solitary intraosseous neurofibroma of the mandible is reported. The tumor was located in the body of the right mandible. Segmental mandibulectomy including the surrounding tissue was performed and the mandible was reconstructed with the free scapular osteocutaneous flap. From histological examination of the resected mandible, typical findings of a tumor invading the adjacent bone along the mandibular nerve were observed. Immunohistochemical examination of the tumor showed positive staining of the tumor cells for anti-S100 protein antibodies. Numerous nerve-like fibers were also noted by Bodian stain.

Adult↗

Replacement of tumor-involved mandible by cryosurgically devitalized autograft: human experience.

In management of a malignant floor-of-mouth tumor invading the mandible, the mandible is the main focus of reconstruction and the most likely site of rehabilitative failure. Creation of a functional and cosmetically appealing replacement is a major therapeutic goal. In canines, neoosteogenesis does occur in mandibular autografts exposed to two consecutive freeze-thaw cycles prior to reimplantation. Also postoperative radiotherapy in canines does not elicit a higher incidence of complications or promote failure of the mandibular autograft to reconstitute itself. This technique was used in a 52-year-old man with a large lesion in the anterior floor of the mouth extending into the inner cortex of the mandible. The theoretical advantages of nonantigenicity and excellence of mandibular configuration are obvious. That there are important pitfalls that may lead to reconstructive failure is equally obvious.

Cryosurgery↗

Mandible reconstruction with microvascular surgery.

Microvascular surgery has become the preferred method for mandible reconstruction. Whenever possible, immediate reconstruction at the time of segmental mandible resection will provide the best aesthetic and functional result. Four donor sites (fibula, iliac crest, radial forearm, and scapula) have become the primary sources of vascularized bone and soft tissue for the reconstruction. The fibula has multiple advantages, including bone length and thickness, donor site location permitting flap harvest simultaneously with tumor resection, and minimal donor site morbidity. The fibula donor site should be the first choice for most defects, particularly those with anterior or large bony defects requiring multiple osteotomies. Use of an alternative donor site is best reserved for cases with large soft tissue and minimal bone requirements. Dental rehabilitation through the use of prostheses and osseointegrated dental implants is an important part of the reconstructive process to optimize aesthetics and function. An algorithm for mandible reconstruction with microvascular osseous flaps is presented. Semin. Surg. Oncol. 19:226-234, 2000.

Bone Transplantation↗

Dysmorphogenesis of the mandible, zygoma, and middle ear ossicles in hemifacial microsomia and mandibulofacial dysostosis.

A review of the anatomical changes in patients with various "first arch" syndromes shows that some anomalies (e.g., micrognathia, ear defects) generally appear together. This study tested the hypothesis that the mandible, zygomatic arch, and middle ear ossicles are a developmental field (i.e., when any of these structures is anomalous, the other two will be also). The hypothesis was tested using data from 25 patients with mandibulofacial dysostosis (MFD) and 40 patients with hemifacial microsomia (HFM). Analysis of the pooled data showed that the hypothesis of character association was generally supported. However, the medians suggested that different factors probably played a role in determining how these three anatomical structures were associated in MFD and HFM. Errors in chondrogenesis may have been primarily responsible for the HFM phenotype. Alterations in Meckel and palatoquadrate cartilages would account for the size and shape changes observed in the ossicles and mandible, while changes in cranial base cartilages may explain the changes noted in the zygomatic arch. Since all three structures were equally affected in MFD, it is problematic to use an interference with chondrogenesis as an explanation for the phenotype. We conclude that although the mandible, zygomatic arch, and middle ear ossicles appear to form a "developmental field," the association between structures varies for HFM and MFD. The relatively lesser involvement of the zygomatic arch in HFM than in MFD suggests different pathogeneses for the two diagnostic groups and maybe a useful criterion for judging animal models of HFM.

Ear Ossicles↗

In vivo bone strain in the mandible of Galago crassicaudatus.

Single element foil strain gages were bonded to mandibular cortical bone in eight specimens of Galago crassicaudatus. The gage was bonded below the Pm4 or M2 adjacent to the lower border of the mandible. The bonded strain gage was connected to form one arm of a Wheatstone bridge. Following recovery from the general anesthetic, the restrained Galago bit either a piece of wood, a food object, or a bite force transducer. During these biting episodes, mandibular bone strain deformed the strain gage and the resulting change in electrical resistance of the gage caused voltage changes across the Wheatstone bridge. These changes, directly proportional to the amount of bone strain along the gage site, were recovered by a strip chart recorder. Bone strain was measured on both the working and balancing sides of the jaws. Maximum values of bone strain and bite force were 435 microstrain (compression) and 8.2 kilograms respectively. During bending of the mandible, the correlation between bone strain (tension or compression) and bite force ranged from -0.893 (tension) to 0.997 (compression). The experiments reported here demonstrate that only a small percentage of the Galago bite force is due to balancing side muscle force during isometric unilateral molar biting. In addition, these experiments demonstrate that the Galago mandible is bent in a predictable manner during biting. The amount of apparent mandibular bone strain is dependent on (1) the magnitude of the bite force and (2) the position of the bite point.

Animals↗

The human mandible: lever, link, or both?

Hylander ('78) recently published important new data on bite force in humans, and showed that the human mandible cannot function purely as a link during incisal biting. He concluded instead that the mandible acts as a lever. Reexamination of Hylander's data suggests that the mandible cannot function purely as a lever either, and in fact it probably functions simultaneously as both lever and link during incisal biting.

Biomechanical Phenomena↗

The relationship between split-line orientation and in vivo bone strain in galago (G crassicaudatus) and macaque (Macaca mulatta and M. fascicularis) mandibles.

There is still disagreement concerning the functional significance of split-line patterns in bone. This study was undertaken to reexamine the mechanical forces hypothesis for split-line formation by comparing split-line patterns with in vivo mandibular bone strain patterns. The relationship between split-line orientation and in vivo stress and strain patterns on macaque and galago mandibles was examined during jaw opening and the power stroke of mastication and incision. An attempt was made to relate split-line orientation to the direction of tensile stress and strain along the primate mandible. In addition, we also investigated the alternative possibility that split-line orientation is related to the direction of low stresses (and strains) on the primate mandible. The results of this study showed that there was no consistent relationship between split-line orientation and the principal strains or stresses. Thus, split-lines did not run consistently in the direction of high or low stress and strain. Therefore, we have concluded that split-line orientation provides little useful information for inferring patterns of stress and strain in bone.

Animals↗

Tooth loss and tooth retention in a multitribal group of Bantu-speaking South African blacks: a study on 500 dry mandibles.

Tooth loss and tooth retention in adult South African Bantu-speaking Negroes were studied from data derived from 500 dry mandibles. The tribe, sex, and stated age of the specimens were available. Mandibles were equally distributed over the third to seventh decade of life. The presence of dental units was recorded and analysed within and between decade age groups. The mandibles carried a total of 5,459 dental units. Between the third and fourth decades of life and between the sixth and seventh decades, the reduction of the frequency of dental units was mild and statistically not significant. It was, however, severe and significant between the fourth and fifth, and the fifth and sixth decades. In the third-decade group, most teeth were found in the anterior region with a tendency to diminish in number posteriorly. After the third decade there was a definite persistence of first premolars and canines with significant tendency toward loss of teeth anterior and posterior to them. Only the incisors and third molars showed significant reduction in number from the third to the fourth decade. The reduction of all teeth was statistically significant later, until the sixth decade of life. Although there was loss of teeth from the sixth to the seventh decade, it was not significant for any of the homologous dental units. There is a possibility that some dietary differences existed between the older subjects (50-70 years old) and the younger ones (20-49 years old) which may have had some influence on the results.

Adult↗