• 대한치과보철학회지
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• 제36권2호
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• pp.203-244
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• 1998

The human mandible is always under the condition of loading by the various forces extorted by the attached muscles. The loading is an important condition of the stomatognathic system. This condition is composed of the direction and amount of forces of the masticatory muscles, which are controlled by the neuromuscular system, and always influenced by the movement of both opening and closing. Mandible is a strong foundation for the teeth or various prostheses, nevetheless it is a elastic body which accompanies deformation by the external forces on it. The elastic properties of the mandible is influenced by the various procedures such as conventional restorative treatments, osseointegrated implant treatments, reconstructive surgical procedures and so forth. Among the treatments the osseointegrated implant has no periodontal ligaments, which exist around the natural teeth to allow physiologic mobility in the alveolar socket. And so around the osseointegrated implant, there is almost no damping effect during the transmission of occlusal stress and displacements. If the osseointegrated implants are connected by the superstructure for the stabilization and effective distribution of occlusal stresses, the elastic properties of mandible is restricted according to the extent of 'splinting' by the superstructure and implants. To investigate the change of elastic behaviour of the mandible which has osseointegrated implant prosthesis of various numbers of implant installment and span of superstructre, a three dimensional finite element model was developed and analyzed with conditions mentioned above. The conclusions are as follows : 1. The displacements are primarily developed at the area of muscle attachment and distributed all around the mandible according to the various properties of bone. 2. The segmentation in the superstructure has few influence on the distribution of stress and displacement. 3. In the load case of ICP, the concentration of tensional stress was observed at the anterior portion of the ramus($9.22E+6N/m^2$) and at the lingual portion of the symphysis menti($8.36E+6N/m^2$). 4. In the load case of INC, the concentration of tensional stress was observed at the anterior portion of the ramus($9.90E+6N/m^2$) and the concentration of tensional stress was observed at the lingual portion of the symphysis menti($2.38E+6N/m^2$)). 5. In the load case of UTCP, the relatively high concentration of tensional stress($3.66E+7N/m^2$) was observed at the internal surface of the condylar neck.

• 대한치과의사협회지
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• 제23권12호통권199호
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• pp.1027-1030
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• 1985

Student male 16 years old fractures of mandible in symphysis and both condyle head, conservative treated intermaxillary wiring (Rubber bands elastic) 2 weeks, mandible movement fractured healed. Patient has practically normal masticatory function and no complaints after treated 10 months.

• 대한치과의사협회지
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• 제17권10호통권125호
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• pp.769-772
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• 1979

Child female 11 years old fractures of mandible in symphysis and left condyle head, conservative treated intermaxillary wiring (Rubber bands elastic) 8 days after mandible movement fractures healed. Patient has practically normal mastic atory function and no complaints.

• 대한치과교정학회지
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• 제37권4호
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• pp.245-259
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• 2007

성장기 아동의 상악골 전방 견인을 이용한 치료 효과 중 하악골의 후하방 회전은 III급 골격관계를 개선시키지만 하안모의 길이가 길어져 face mask가 장안모 환자에게는 비적응증 이라는 것이 선학들의 일반적 견해였다. 그러나 실제로 하안모의 길이를 분류 기준으로 삼아 이에 따른 치료 효과를 비교한 연구는 부족한 실정이며 경조직 변화에 따른 연조직 변화의 연구 또한 미비하였다. 본 연구에서는 상악골 열성장을 보이는 성장기 골격성 III급 부정교합 환자 44명을 Ricketts의 lower facial height (LFH)기준에 따라 LFH가 정상 수치 이상인 군(1군)과 미만인 군(2군)으로 분류하여, 상악골 전방 견인 시 두 군간의 경조직, 연조직 치료 효과를 비교하고 경조직과 연조직의 상호 관계를 비교 분석하여 다음과 같은 결론을 얻었다. 상악의 경조직, 연조직 전방 이동량은 두 군간에 유의한 차이가 없었다. 하악의 경조직 후방이동량은 두 군간에 유의한 차이가 없었으나 연조직 후방이동량은 2군에서 더 크게 나타났다. 하안면의 경조직 수직 비율 변화는 두 군간에 유의한 차이가 없었으나 연조직 수직 비율 변화는 2군에서 더 크게 나타났다. 상악과 하악의 전후방적 경조직, 연조직 변화는 유의한 상관관계를 갖는 반면 수직적 하안면 비율 변화는 유의한 상관관계를 갖지 않았다. 위의 결과들을 고려해 볼 때 Face mask 사용 결과 상악골의 전방 이동과 하악골의 후하방회전이 일어났으며 하악의 연조직 후방 이동량은 단안모에서 더 크게 나타났다.

• 대한치과교정학회지
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• 제14권1호
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• pp.75-92
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• 1984

This study attempted to analyze the distribution of stress, to examine the bending effect in the mandible according to the pulling directions and determine on which pulling directions are adequate when an orthopedic force was applied to the mandible. An orthopedic force, 500gm, was applied to the gnathion, one point of the chin area, in three directions. The three directions were ; high puli' from gnathion to the center of condyle head, and vertical pull, from gnathion to a parallel line with the posterior border of the ramus, and medium pull, from the gnathion to a parallel line with the lower border of mandible. The distribution of principal stress, bending moment and amount of displacement within the mandible was analyzed by a 3-dimensional finite element method and that of the various portions of mandible were computed and compared according to the pulling directions. The results were as follows : 1. The bending moment of each part of a mandible has been found to be markedly larger in case of vertical pull than in case of either high pull or medium pull. In vertical pull the bending moment turned out to largest at the condyle head and neck portion, the gonial angle portion, the coronoid portion and the ascending ramus portion, respectively, while comparatively large at the cuspid and bicuspid portion and the first molar portion. In case of high pull it was largest at the gonial angle portion and becoming smaller at the coronoid portion, the ascending ramus portion, the condyle head and neck portion, and the cuspid and bicuspid portion, in that order. In case of medium pull, however, the bending moment was largest at the condyle head and neck portion, becoming smaller at the first molar portion, the ascending ramus portion, the coronoid portion, the cuspid and bicuspid portion, and gonial angle portion, in that order. 2. As for the bending effect it was calculated to be mostly oriented downward at the mandibular body and backward at the mandibular ramus in both high pull and vertical pull. In case of medium pull it was oriented upward at the mandibular body and forward at the mandibular ramus. 3. The bending effect also turned out to be mostly oriented outward in case of high pull and medium pull, and inward in vertical pull. 4. At the mandibular body and ramus, the bending effect in the upward-downward direction and that in the forward-backward direction were found to be larger than in the inward-outward direction. 5. If and when we expect any correcting effect on the mandibular protrusion by means of the chin cup appliance, we can say sure as conclusion that high pull and vertical pull are more effective than medium pull.

• 치과방사선
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• 제29권2호
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• pp.549-559
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• 1999

Leiomyosarcoma is extremely rare in the oral cavity and especially in the mandible. At first. the case of this report was diagnosed as odontogenic fibroma but after approximately 3.5 years. it was diagnosed as leiomyosarcoma. Conventional radiograph of the first time showed an ill-defined radiolucent lesion in the mandible. After local recurrence. CT images showed a large irregular soft tissue mass with some necrotic areas. These findings were not specific for leiomyosarcoma, but they suggested that this lesion was a recurrent soft tissue sarcoma. Histopathological examinations using H & E staining, immunohistochemical staining and Masson's trichrome staining confirmed this case as leiomyosarcoma. Deciding its malignancy or benignancy, defining the tumor extent and its relationship to the surrounding anatomic structures, and evaluating the distant metastasis are more important roles of radiographic examination than finding out the name of disease.

• Imaging Science in Dentistry
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• 제37권4호
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• pp.217-220
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• 2007

Purpose: The purpose of this study was to compare the location of the mandibular canal in Class III malocclusion to its location in normal occlusion for adults. Materials and Methods: For this study 32 skeletal Class III patients and 26 normal patients were observed. Four measurements were taken on cross sectional tomography between the first and second molars: the distance from the mandibular canal to the inner surface of both the buccal and lingual cortices, the distance from the mandibular canal to the inferior border of the mandible, and the buccolingual width of the mandible. The buccolingual location of the canals was classified as lingual, central, or buccal. Each measurement was analyzed with an independent t test to compare Class III malocclusion to normal occlusion. Results: Compared to the control group, the prognathic group had a shorter distance from the canal to the inner surface of the lingual cortex and to the base of the mandible. A higher percentage of the canals were located lingually in the prognathic group. Conclusion: This study showed that the mandibular canal was located more lingually and inferiorly in prognathic patients than in patients with normal occlusion. These results could help surgeons to reduce injuries to the inferior alveolar nerve.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제17권2호
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• pp.180-185
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• 1995

TMJ ankylosis is classified with true and false type. A true ankylosis is defined as any condition that produces fibrous or bony adhesions between the articular surfaces of the temporomandibular joint. The main causes of true ankylosis are trauma or infection. A false ankylosis results from pathologic conditions outside the joint that limit mobility of the mandible such as myogenic disorders, coronoid impingement or rare direct bony fusion between maxilla and mandible. The treatment of choice of TMJ ankylosis is surgical intervention. We experienced the male patient with complete mouth opening limitation since 45 years before. This patient has true TMJ ankylosis and rare bony synostosis between maxilla and mandible in the right posterior region. We performed surgical intervention and had a favorable result.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권6호
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• pp.649-652
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• 2008

Osteoblastoma is a relatively rare benign bone tumor representing less than 1% of all bone tumors. The tumor usually involves the spine and sacrum of young individuals, less than 10% being localized to the skull, and nearly half of these affect the mandible, especially the posterior segments. In clinical finding, osteoblastoma present mainly with pain, swelling, and expansion of bone cortex. Radiographic appearances are variable, but frequently a well-delineated radiolucent lesion containing varying amounts of mineral deposits is seen. Histologically, ostoeblastoma is consists of irregular trabeculeae of osteoid and immature bone present within highly vascular connective tissue matrix. Osteoblastoma must be differentiated from a number of bone-producing lesions, including osteoid osteoma, fibrous dysplasia, ossifying fibroma, fibrous dysplasia, and osteosarcoma. If diagnosis may be mistaken for osteosarcoma, there are risks of more aggressive and irreversible treatment. Differential diagnosis of osteoblastoma is important. The preferred treatment of osteoblastoma is conservative approach and surgical excision. Recurrence following surgical intervention is rare. We treated osteoblastoma located in premolar area of mandible by excision with preservation of vital structure, such as nerves and teeth. So we report our clinical treatment with literature review

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권5호
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• pp.471-477
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• 2001

Failure to use effective methods of reduction, fixation, and immobilization may lead to nonunion with osteomyelitis, owing to the compound nature of most fractures of the mandible. Nonunion results in fibrous pseudoarthrosis at the fracture site with instability that, once formed, does not improve spontaneously. Once the nonunion with osteomyelitis secondary to fractures has become established, intermaxillary fixation and drainage of infected tissue should be instituted as early as possible, because the fixation & drainage enhances the patient comfort and hinders ingress of microorganisms & debris by movement of bone fragments. The authors treated three cases of nonunion with osteomyelitis by intermaxillary fixation, incision & persistent drainage on the previous fistula site and endodontic drainage of infected teeth in the fracture site of mandible. The localization & sequestration of the infected bone around the fracture was better performed persistently by natural homeostatic mechanism in $8{\sim}10$ weeks and the bony union was then attained without bone grafting.