• 대한두개안면성형외과학회지
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• 제13권2호
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• pp.151-155
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• 2012

Purpose: Basal cell adenoma of the salivary gland is an uncommon type of monomorphic adenoma. The most frequent location is parotid gland. It usually appears as a firm, mobile and slow-growing mass. Originally the term "basal cell adenoma" is described as a benign salivary gland tumor comprised of uniform appearing basaloid cells which are arranged in solid, trabecular, tubular, and membranous patterns. But the myxoid and chondroid mesenchymal like component as seen in pleomorphic adenoma is lacking in basal cell adenoma. We report a case of basal cell adenoma of parotid gland with review of the literatures. Methods: The 59-year-old female patient was referred to our department with a painless palpable mass in the left preauricular region for about 1 year. Movable and nontender subcutaneous mass was palpable. There was no evidence of cervical metastasis in computed tomography and ultrasonography. On fine needle aspiration cytology, pleomorphic adenoma was suspected. Under general anesthesia, superficial parotidectomy including tumor was performed. The biopsy result was basal cell adenoma. Results: Long-term follow-up for 54 months showed favorable result without evidence of recurrence except for temporary facial nerve weakness right after the surgery. Conclusion: Basal cell adenoma is the third most frequent benign tumor of the salivary gland, following pleomorphic adenoma and Warthin's tumor, although the incidence is low. The typical clinical feature of the basal cell adenoma is slowly growing, asymptomatic, and freely movable parotid mass. Basal cell adenoma should be also considered as a differential diagnosis of the parotid gland benign tumor.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권5호
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• pp.454-469
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• 2006

Today, there is considerable evidence to support a cause-effect relationship between microbial colonization and the pathogenesis of implant failures. The presence of bacteria on implant surfaces may result in an inflammation of the peri-implant mucosa, and, if left untreated, it may lead to a progressive destruction of alveolar bone supporting the implant, which has been named as peri-impantitis. Several maintenance regimens and treatment strategies for failing implants have been suggested. Recently, in addition to these conventional tools, the use of different laser systems has also been proposed for treatment of peri-implant infections. As lasers can perform excellent tissue ablation with high bactericidal and detoxification effects, they are expected to be one of the most promising new technical modalities for treatment of failing implants. It is introduced that Er,Cr:YSGG laser, operating at 2780nm, ablates tissue by a hydrokinetic process that prevents temperature rise. We studied the change of the titanium implant surface under scanning electron microscopy after using Er,Cr:YSGG laser at various energies, irradiation time. In this study, Er,Cr:YSGG laser irradiation of implant fixture showed different effects according to implant surface. Er,Cr:YSGG laser in TPS surface with RBM not alter the implant surface under power setting of 4 Watt(W) and irradiation time of 30sec. But in TPS surface with $Ca_3P$ coating alter above power setting of 2W and irradiation time of 10sec. TPS surface with RBM showed microfracture in 4W, 30sec and TPS surface with $Ca_3P$ coating showed destruction of fine crystalline structure, melting in excess of 2W, 10sec. We concluded that proper power setting, air, water of each implant surface must be investigated and implant surface must be irradiated under the damaged extent.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권4호
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• pp.414-417
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• 1999

The congenital epulis of newborn is a rare benign tumor that occurs on the gingiva of the anterior alveolar ridge of the jaws, also known as a congenital granular cell tumor. Females are affected 8 - 10 times more often than males. The typical location is the alveolar ridge of the maxilla near the canine but the mandibular region can also be involved. The lesion may be sessile or pedunculated with red or normal color. The size of tumor varies from several millimeters to a few centimeters in diameter. Surgical excision is generally indicated and no recurrences have been noticed. Spontaneous regression is rare. It is histologically similar to the granular cell tumor, although pseudoepitheliomatous hyperplasia does not occur in the former lesion. Thus sheets of large, closely packed cells showing fine, granular, eosinophilic cytoplasm comprise the tumor mass. This is a case report of congenital epulis in the fetus. The lesion was detected in ultrasonogram, its size is 3cm in diameter. The infant showed nursing disturbance and respiratory obstruction after birth, so the tumor was surgically excised under local anesthesia.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제17권3호
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• pp.239-252
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• 1995

The present study was aimed to evaluate the effect of demineralized freeze-dried bone (DFDB) and resorbable hydroxyapatite (RHA) on bone formation in the extracted socket. The lower left and right 2nd and 3rd premolar were extracted in adult dogs. The one group was grafted with DFDB into the extracted socket, and the other group grafted with RHA. The extracted socket was sutured without any graft materials as control. The animals were killed on the 1st, 2nd, 4th, and 8th week after the graft for macroscopic and microscopic examination. Results obtained were as follows : 1. Macroscopically, nor infection of the graft site and dislodgement of the grafted material were noted in any animals used. 2. Young trabeculae of osteoid were formed in the socket wall in control group at 2 weeks after the graft. Osteoid tissue was formed in DFDB group at 1 week after graft, and a fine osteoid tissue was grown through the RHA particles in RHA group at 2 weeks graft. 3. The grafted groups showed more rapid bone formation than the control. Between the grafted groups, DFDB group showed more rapid formation than RHA group, DFDB group showed osteoinductive bone formation and RHA group showed osteoconductive bone formation. These results suggest that DFDB and RHA are useful to preserve the alveolar bone and to improve new bone formation by immediate grafting into the extraction sockets.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.30.1-30.7
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• 2017

Background: The positions of the mandibular lingula and foramen have been set as indexes for inferior alveolar nerve (IAN) block and ramus osteotomies in orthognathic surgery. This study aimed to evaluate the anatomical structures of mandibular ramus, especially the mandibular lingula and foramen, by analyzing the cone-beam computed tomography (CBCT) data of young adults. Methods: We evaluated 121 sides of hemi-mandibular CBCT model of 106 patients (51 male and 55 female patients; 18 to 36 years old). All the measurements were performed using the 2- and 3-dimensional rulers of $OnDemand3D^{(R)}$ software. Results: Statistical analysis of the data revealed that there was no significant difference in the mandibular angle between the genders. The mandibular lingula was found to be located at the center of ramus in males, but a little posterior in relation to the center in females. The mandibular lingula was rarely located below the occlusal plane; however, the position of the mandibular foramen was more variable (84.3% below, 12.4% above, and 3.3% at the level of the occlusal plane). Conclusions: The results of this study provide a valuable guideline for IAN block anesthesia and orthognathic surgery. CBCT can be considered effective and accurate in evaluating the fine structures of the mandible.

• International Journal of Precision Engineering and Manufacturing
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• 제8권2호
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• pp.38-43
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• 2007

This paper describes ultrasonically assisted grinding used to obtain a glossy surface quickly and precisely. High-quality surfaces are required for plastic injection molding dies used in the production of plastic parts such as dials for cellular phones. Traditionally, in order to finish the dies, manual polishing by a skilled worker has been required after the machining processes, such as electro discharge machining (EDM), which leaves an affected layer, and milling, which leaves tooling marks. However, manual polishing causes detrimental geometrical deviations of the die and consumes several days to finish a die surface. Therefore, a machining process for finishing dies without manual polishing to improve the surface roughness and form accuracy would be extremely valuable. In this study, a 3D positioning machine equipped with an ultrasonic spindle was used to conduct grinding experiments. An electroplated diamond tool was used for these experiments. Generally, diamond tools cannot grind steel because of excessive wear as a result of carbon atoms diffusing into bulk steel and chips. However, ultrasonically assisted grinding can achieve a fine surface (roughness Rz of $0.4{\mu}m$) on die steel without severe tool wear. The final aim of this study is to realize mirror surface grinding for injection molding dies without manual polishing. To do this, it is necessary to fabricate an electroplated diamond tool with high form accuracy and low run-out. This paper describes a tool-making method for high precision grinding and the grinding performance of a self-electroplated tool. The ground surface textures, tool performance and tool life were investigated A ground surface roughness Rz of 0.14 um was achieved Our results show that the spindle speed, feed rate and cross feed affected the surface texture. One tool could finish $5000mm^2$ of die steel surface without any deterioration of the ground surface roughness.

• 한국토양비료학회지
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• 제34권2호
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• pp.92-97
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• 2001

염류가 집적된 시설재배지의 강서 미사질 양토에서 1999년부터 2년간 무처리, 심토반전, 심토파쇄, 폭기식 심토파쉐 및 암거배수 등 5개 처리를 하여 토양의 물리적 성질과 작물 생산성을 비교시험하였다. 1. 심토의 물리성 개선효과는 심토반전 > 암거배수 > 심토파쇄 > 무처리 순으로 높았고 2년차까지 잔효가 인정되었으며 토양물리성 개선처리는 통기성을 높이고 근권을 확대시켰다. 2. 심토의 토양수분함량은 심토반전 > 암거배수 > 심토파쇄 > 무처리 순으로 높았으나 큰 차이는 없었다. 또한 토양물리성 개선처리는 무처리구에 비하여 토층내 시기별 토양수분함량 변동폭을 크게 하였다. 3. 토양물리성 개선처리에 의한 토층내 염농도 저하효과는 적었으며 토양물리성 개선구의 수량증대는 염농도 저하나 토층내 양수분 분포개선 보다는 물리성 개선효과가 더 높은 것으로 판단되었다. 4. 토양물리성 개선처리에 의한 평균수량 증대효과는 10~20%정도 이었다.

• 한국지반공학회논문집
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• 제39권2호
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• pp.5-17
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• 2023

본 연구에서는 국내 국지성 호우의 증가로 인한 피해의 보호효과가 탁월한 지반개량제를 표층개량공법에 활용하기 위해 붕괴된 15개소의 현장토를 대상으로 흙의 분류 및 일축압축시험을 진행하여 토질별 최적배합비를 제안하는 연구를 진행하였다. 현장토에 대해 Casagrande법과 원추관입시험법을 실시하여 액·소성한계값의 비교, 흙의 분류 및 서로의 상관관계에 대한 관계식을 유도하였다. 각각의 흙의 분류에 대해 일축압축강도를 이용하여 지반개량제의 최적 배합비를 도출한 결과, Casagrande법으로 분류한 경우 실험자의 숙련도 차이와 시험의 오차에 의해 세립토의 분류가 명확하지 않았지만, 원추관입시험법으로 분류하였을 때 명확한 최적 배합비를 제안할 수 있었다.

• Archives of Plastic Surgery
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• 제50권3호
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• pp.248-253
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• 2023

Metal fixation systems for cranial bone flaps cut by a drill are convenient devices for cranioplasty, but cause several complications. We use modified craniotomy using a fine diamond-coated threadwire saw (diamond T-saw) to reduce the bone defect, and osteoplasty calcium phosphate cement without metal fixation. We report our outcomes and tips of this method. A total of 78 consecutive patients underwent elective frontotemporal craniotomy for clipping of unruptured intracranial aneurysms between 2015 and 2019. The follow-up periods ranged from 13 to 66 months. The bone fixation state was evaluated by bone computed tomography (CT) and three-dimensional CT (3D-CT). The diamond T-saw could minimize the bone defect. Only one wound infection occurred within 1 week postoperatively, and no late infection. No pain, palpable/cosmetically noticeable displacement of the bone flap, fluid accumulations, or other complications were observed. The condition of bone fixation and the cosmetic efficacy were thoroughly satisfactory for all patients, and bone CT and 3D-CT demonstrated that good bone fusion. No complication typical of metal fixation occurred. Our method is technically easy and safety, and achieved good mid-term bone flap fixation in the mid-term course, so has potential for bone fixation without the use of metal plates.

• 한국구조물진단유지관리공학회 논문집
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• 제28권2호
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• pp.69-76
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• 2024

굳지 않은 콘크리트의 유변특성은 콘크리트의 제조 및 성능에 중요한 영향을 미치지만, 새롭게 개발되는 배합과 제조 공법의 다양화로 인하여 기존의 경험적 방법으로는 유변특성의 정확한 예측에 어려움이 있다. 본 연구에서는 시멘트 입자와 같은 나노 수준에서의 입자간 상호작용부터 잔골재와 같은 마이크로 수준에서의 유변학적 성질을 정량적으로 예측하기 위하여 멀티스케일 기법을 적용한 유변특성 예측 모델을 제안하였으며, 시멘트 페이스트의 항복응력, 모르타르의 항복응력 및 소성점도를 예측하기 위하여 YODEL(Yield stress mODEL), Chateau-Ovarlez-Trung 방정식 및 Krieger-Dougherty 방정식을 적용하였다. 일차적으로 시멘트 페이스트의 물-시멘트비(W/C)를 기준으로 하여 페이스트 스케일의 유변특성을 예측하였으며, 예측 결과를 토대로 동일한 W/C에 시멘트-잔골재 부피비(C/S)를 추가한 모르타르 스케일의 유변특성의 예측을 진행하였다. 시멘트 모르타르에 대한 유변특성 실험을 통하여 예측 결과와 실험 결과의 비교를 진행함으로써 예측 모델의 적용 가능성을 평가하였다.