• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권3호
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• pp.232-237
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• 2001

The purpose of this study was to find the clinical features of periapical lesions. A total of 130 periapical lesions which were obtained from biopsy and diagnosed histopathologically as periapical cyst, periapical abscess, and periapical granuloma at the Department of Dentistry in Hanyang University Hospital were throughly analysed according to the distribution and incidence of age, sex, location, and so on. The following results were obtained : 1. Out of 130 periapical lesions, 88 cases(67.7%) were periapical cysts, 30 cases(23.1%) were periapical abscesses, and 12 cases(9.2%) were periapical granulomas. 2. The periapical lesions occurred most frequently in the third decade, and followed by the fourth, fifth, sixth, and second decade. The periapical cysts occurred most frequently in the third decade(26.1%), the periapical granulomas in the fourth decade(33.3%) the periapical abscesses in the sixth decade(26.7%). 3. The periapical lesions were more frequent in men than in women with the ratio of men to women of 1.4 : 1. The radio of men to women of periapical cysts was 1.6 : 1, that of periapical granulomas was 0.5 : 1, and that of periapical abscesses was 1.3 : 1. 4. The periapical lesions were more frequent in maxilla than in mandible with the ratio of 1.2 : 1. The ratio of maxilla to mandible of periapical cysts was 1.5 : 1, that of periapical granulomas was 0.5 : 1, that of periapical abscesses was 1 : 1. 5. The most commonly involved location of the periapical lesions was maxillary anterior teeth(40.8%), and followed by mandibular molars, mandibular premolars, and mandibular anterior teeth and maxillary molars. The most frequent location of the periapical cysts was maxillary anterior teeth(48.9%), that of periapical granulomas was mandibular molars(50.0%), that of periapical abscesses was mandibular molars(40.0%).

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권4호
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• pp.647-651
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• 1996

Langerhans cell histiocytosis(LCH) appears to arise from Langerhans cell and comprises a spectrum of clinical disease previously described in the literature by a variety of eponyms including histiocytosis X, eosinophilic granuloma, Hand-Schuller-Christian disease, and Letterer-Siwe syndrome. This rare disorder occurs in all groups, predominently affecting children & young adults. LCH has a wide spectrum of clinical features. The differentiation of several forms of this disease is primarily a clinical and not a histologic one. The radiographic characteristics include the appearance of solitary "intraosseous" lesions, the multiplicity of "alveolar bone" lesions, the bone lesions, periosteal new bone formation, and slight root resorption. Prognosis of a single bone lesion, is known to be excellent. In contrast, disseminated disease has seen associated with a chronic course, a high rate of morbidity and late consequences, and possible mortality. Treatment of LCH remains problematic. Treatment of multisystem disease, where organ function is being compromised has generally been with high-dose systemic corticosteroids or multiple chemotherapy.

• Journal of Mechanical Science and Technology
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• 제20권7호
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• pp.1002-1011
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• 2006

In this study, we describe the conventional hot pressing (CHP) of layered $Al-B_4C$ composites and their characterization. The matrix alloy Al-5 wt.%Cu was prepared from elemental powder mixtures. The metal and B4C powders were mixed to produce either $Al-Cu-10vol.%B_4C$ or $Al-Cu-30vol.%B_4C$ combinations. Then, these powder mixtures were stacked as layers in the hot pressing die to form a two-layered composite. Hot pressing was carried out under nitrogen atmosphere to produce $30\times40\times5mm$ specimens. Microstructural features and age hardening characteristics of composites were determined by specimens cut longitudinally. The flexural strength of both layered composites and their monolithic counterparts were investigated via three point bending tests. In the case of layered specimens of both $10vol.%B_4C$ and $30vol.%B_4C$ containing layers were loaded for three-point test. The results show that a homogeneous distribution of $B_4C$ particles in the matrix alloy which is free of pores, can be obtained by CHP method. The ageing behavior of the composites was found to be influenced by the reinforced materials, i.e. higher hardness values were reached in 8 hrs for the composites than that for the matrix alloy. Flexural strength test showed that two-layered composites exhibited improved damage tolerance depending on layer arrangement. Microstructural investigation of the fracture surfaces of the bending specimens was performed by means of scanning electron microscope (SEM). While layer with lower reinforcement content exhibited large plastic deformation under loading, the other with higher reinforcement content exhibited less plastic deformation.

• Journal of International Society for Simulation Surgery
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• 제4권1호
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• pp.9-12
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• 2017

Purpose Surgery for separating craniopagus twins involves many critical issues owing to complex anatomical features. We demonstrate a 3D printed model and virtual reality (VR) technologies that could provide valuable benefits for surgical planning and simulation, which would improve the visualization and perception during craniopagus surgery. Material & Methods We printed a 3D model extracted from CT images of craniopagus patients using segmentation software developed in-house. Then, we imported the 3D model to create the VR environment using 3D simulation software (Unity, Unity Technologies, CA). We utilized the HTC Vive (HTC & Valve Corp) head-mount-display for the VR simulation. Results We obtained the 3D printed model of craniopagus patients and imported the model to a VR environment. Manipulating the model in VR was possible, and the 3D model in the VR environment enhanced the application of user-friendly 3D modeling in surgery for craniopagus twins. Conclusion The use of the 3D printed model and VR has helped understand complicated anatomical structures of craniopagus patients and has made communicating with other medical surgeons in the field much easier. Further, interacting with the 3D model is possible in VR, which enhances the understanding of the craniopagus surgery as well as the success rate of separation surgery while providing useful information on diagnosing and surgery planning.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권4호
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• pp.383-387
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• 1998

The mucoepidermoid carcinoma is classified as either well, moderately, or poorly differentiated. The criteria used to classify the lesions are discussed, and pathologic features are illustrated. The most important factors in prognosis are : 1. degree of histologic differentiation, and 2. presence or abscence of tumor on the lines of surgical excision. Recurrences rates are correlated with histologic differentiation. Stewart, Foote, and Becker in 1945 coined the term "mucoepidermoid tumor" to discribe an unusual salivary neoplasm containing epidermoid and mucus-secreting cells which was thought to arise in salivsary gland ducts. The treatment of the mucoepidermoid carcinoma is chiefly surgical, although recent data have shown favorable responses to radiation therapy. Currently, surgery followed by radiation treatment is recommended for intermediate-grade and high-grade tumors ; low-grade tumors can be managed by surgery alone. Authors present a case of mucoepidermoid carcinoma managed with wide surgical resection and postoperative irradiation and showing a good clinical result with review of literatures.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권5호
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• pp.415-423
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• 2005

Distraction osteogenesis (DO) is frequently used technique in reconstruction of bony defects resulted from tumor resection, congenital deformity, and trauma in the maxillofacial region. Although the histologic and ultrastructural changes associated with distraction osteogenesis have been extensively described, the exact changing of the surrounding tissues, such as nerve tissues, were still unclear. This study observed the histological changes and the expression of nerve growth factor (NGF) in the inferior alveolar nerve (IAN) after distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in eight mongrel dogs. Two animals were sacrificed at 7, 14, 28 and 56 days after completion of distraction, respectively. The distracted IAN and contralateral control nerve were harvested and processed for histological and innunohistochemical examinations. The signs of acute nerve injuries, such as demyelination and partial discontinuation of nerver fiber, were observed in the distracted IAN on 7 and 14 days after distraction. The initial remyelination and regeneration of distracted IAN were showed at 14 days after completion of distraction. At 56 days later, the histologic features of distracted IAN was similar to those of the normal control IAN. The expression of NGF was significantly increased in most distracted nerve tissues on 7, 14 and 28 days after distraction. On 56 days after distraction, the expression of NGF returned to the normal level. This study suggested that the acute IAN injury caused by mandibular distraction were mostly recovered during consolidation period. The NGF was seemed to be induced from Schwann cell and damaged nerve tissues, and it may have important roles in the initial healing of damaged nerves.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권3호
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• pp.189-194
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• 2013

Osteochondroma is a benign neoplasm, osseous projection surrounded with cartilage, 35.8% of benign osseous tumor, 8.5% of whole osseous tumor and usually arises from the skeletal bone. Osteochondroma is a cartilaginous derivation and relatively uncommon in the craniofacial bone. Osteochondroma of the mandible has slow growth rates which mainly affect women around forty years of age and it can appear through the coronoid process and mandibular condyle, especially in the medial half. Clinical finding associated with osteochondroma of condyle are primarily a palpable, painless temporomandibular area mass with facial asymmetry, malocclusion and midline deviations. Sometimes pain and dysfunction like trismus often accompany the anatomic derangement. Other features include malocclusion with open-bite on the affected side and cross-bite on the contralateral side. In this study, a 45-years old female patient exhibits pain on the left temporo-mandibular joint area and malocclusion due to loss of the molar region with osteochondroma on the top left of her mandibular condyle head. The patient is able to recover gradually from the symptom through treatments on manipulation, stabilization splint, arthroscopic lavage and surgical excision, thus, this is reported as a clinical case.

• Applied Microscopy
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• 제41권3호
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• pp.147-154
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• 2011

후방산란전자(BSE)는 입사전자빔이 시료와 충돌하면서 발생한다. BSE 이미징은 시료의 화학적 특성을 구분할 수 있는 조성대비를 제공한다. 집속이온빔장치(FIB)는 전계방사형 주사전자현미경(FESEM)과 결합할 수 있으므로 이중빔 체계(FIB-FESEM)가 구현된다. 갈륨(Ga) 이온빔으로 10~100 nm 두께로 시료를 절삭할 수 있으므로 FIB-FESEM은 플라스틱으로 포매된 블록의 면을 z축 고해상도를 유지하며 연속적으로 이미징할 수 있다. BSE이미지의 대비를 반전시키면 투과전자현미경의 이미지와 유사하다. 연속블록면 이미징의 또 다른 방안으로써 특수한 초박절편기가 FESEM 내부에 장착된 것이 $3View^{(R)}$로 상용화되어 있다. 이로써 플라스틱으로 포매된 시료의 내부 구조를 넓은 면적을 연속적으로 이미징 할 수 있으므로 3차원 재구성도 용이하게 된다. 이러한 FESEM에 기반한 두 가지 방식은 복잡한 생물계의 총체적인 이해를 위하여 세포 및 세포 수준 이하의 구조물 간의 공간적 연관성을 규명하는 데 활용될 수 있다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권4호
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• pp.395-400
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• 1999

Elongation of the styloid process (styloid syndrome, Eagle's Syndrome) is named after Eagle who insisted the styloid process as a cause of pain but distinguishable from the glossopharyngeal neuralgia. Eagle's syndrome is characterized by a dull nagging pharyngeal pain, a palpable hardness in the tonsillar fossa, radiopaque elongation and enlargement of the syloid process. This is to report two cases of Eagle's Syndrome. The clinical and radiological features, development and pathogenesis of the Eagle's Syndrome and pathologic findings of the calcified styloid ligaments were described with review of literatures. The external cervical approach to resect the enlarged calcified processes can be an option due to better visualization and accessbility, less infection at risk than intra-oral approach. The findings and results were as follows ; 1. The calcified styloid ligaments accompanied with throat pain were reseded in size of $5.5{\times}48mm(#1,\;Rt)$, $3.6{\times}5mm(#1,\;Lt)$, $5.2{\times}51mm(#2,\;Rt)$ and $3.1{\times}38mm(#2,\;Lt)$. 2. The submandibular approach to resect the calcified styloid process is of help to get better visibility and accessiblilty avoiding the injury to the deep cervial vital structures. 3. The resected styloid processes were examined histopathologically as the matured cortical bones with marrow structures or cartilagenous cells without any findings of neoplasmic changes. 4. The remained process did not show any noticeable regrowth in 3 years after surgical amputation.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권1호
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• pp.74-80
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• 1999

본 교실에서는 가족력을 가지며, 하악에 다발성으로 재발된 치성각화낭종의 증례가 있어 보고하는 바이다. 환자들은 한 가족의 어머니와 두 자녀였으며 그중 어머니와 딸의 경우 낭종적출후 수차례의 재발을 보여 딸은 앞으로도 수술을 예정하고 있다. 낭종이외의 다른 기저세포모반증후군의 증거는 보이지 않았다. 처치로서 어머니와 딸의 경우 낭종적출술을 시행하였고 아들의 경우 낭종적출후 결손부의 크기가 커서 동종골이식을 시행하였다. 현재 어머니와 아들의 경우 재발은 보이지 않고 있으나 향후 지속적인 구강검사를 통해 관리예정이며 유전학적인 검사도 고려하고 있다.