• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.4
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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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• v.20 no.7
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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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• v.4 no.1
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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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• v.20 no.4
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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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• v.27 no.5
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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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• v.35 no.3
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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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• v.41 no.3
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• pp.147-154
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• 2011

Backscattered electrons (BSE) are generated at the impact of the primary electron beam on the specimen. BSE imaging provides the compositional contrast to resolve chemical features of sectioned block-face. A focused ion beam (FIB) column can be combined with a field emission scanning electron microscope (FESEM) to ensure a dual (or cross)-beam system (FIB-FESEM). Due to the milling of the specimen material by 10 to 100 nm with the gallium ion beam, FIB-FESEM allows the serial block-face (SBF) imaging of plastic-embedded specimens with high z-axis resolution. After contrast inversion, BSE images are similar to transmitted electron images by transmission electron microscopy. As another means of SBF imaging, a specialized ultramirotome has been incorporated into the specimen chamber of FESEM ($3View^{(R)}$). Internal structures of plastic-embedded specimens can be serially revealed and analyzed by $3View^{(R)}$ with a large field of view to facilitate three-dimensional reconstruction. These two SBF approaches by FESEM can be employed to unravel spatial association of (sub)cellular entities for a comprehensive understanding of complex biological systems.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.4
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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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• v.21 no.1
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• pp.74-80
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• 1999

A family is presented in which multiple odontogenic keratocysts have been expressed. 3 members of the two generations of family with features of multiple keratocysts, suspected basal cell nevus syndrome have been investigated. The proband, 19-year-old woman and her mother, and her brother suffered from these cysts and two female patients' disease have been recurred multiply though careful treatments. Close attention to the family and routine follow up will alert the clinician to its recurrences and genetic counseling and serial screening for the development of other symptoms, that is malignant skin carcinoma etc.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.1_2
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• pp.160-168
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• 1992

Ameloblastoma is an aggressive but benign epithelial neoplasm of odontogenic origin, and the occurrence of odontogenic epithelium in the wall of a dentigerous cyst is well-known entity. The presence of ameloblastic proliferation in the walls of odontogenic cysts has been reported for many years. Cahn in 1933 described a case in which he considered an ameloblastoma to have originated in a dentigerous cyst, and numerous other cases of ameloblastomatous proliferation have since been reported. In 1977, Robinson and Martinez described a distinct variant of ameloblastoma in which the response to curettage was found to be favorable with a recurrence rate of 25%. The gross and microscopic features indicated that this variant vas associated with a large cystic cavity with either luminal or mural proliferation of ameloblastic tumor cells, and they referred to this variant as unicystic ameloblastoma. Unicystic ameloblastoma occurs most commonly in the second and third decades of life, which is considerably younger than the average age of discovery for the classical ameloblastoma. For the accurate histopathological diagnosis of the unicystic ameloblastoma, the specimen obtained the excisional biopsy, complete enucleation or incisional biopsy from the multiple site of the lesion. This article provides histopathologic evidence of multilocular unicystic ameloblastoma in which ameloblastic tissue was associated with a dentigerous cyst that was found in a 31-year-old female, and complete radiographic, photographic, and microscopic documentation is presented.