• 한국기계가공학회지
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• 제12권6호
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• pp.77-83
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• 2013

Orthodontics is a branch of dentistry that is concerned with the study and treatment of malocclusion, which may result from tooth irregularities, disproportionate jaw relationships, or both. Orthodontic devices consist of brackets, archwire connected to each bracket, and bends and hooks for auxiliary functions. Basically, orthodontics involves the interaction of brackets and archwire. It should be noted that uncontrolled tipping can occur due to unwanted movement of the teeth. The bending of an archwire can control the angle of an archwire and the rotation of a tooth. In this study, we predict the relationship between the bending angle of an archwire and the rotation of a tooth using the Kriging interpolation method. Also, we calculate the angle of an archwire that occurs at the minimum value of tooth rotation.

• Geomechanics and Engineering
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• 제10권6호
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• pp.775-791
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• 2016

The indirect tensile strengths (ITSs) of different cemented paste backfill mixes with different curing times were determined by considering crack initiation and fracture toughness concepts under different loading conditions of steel loading arcs with various contact angles, flat platens and the standard Brazilian test jaw. Because contact area of the ITS test discs developes rapidly and varies in accordance with the deformability, ITSs of curing materials were not found convenient to determine under the loading apparatus with indefinite contact angle. ITS values increasing with an increase in contact angle can be measured to be excessively high because of the high contact angles resulted from the deformable characteristics of the soft paste backfill materials. As a result of the change of deformation characteristics with the change of curing time, discs have different contact conditions causing an important disadvantage to reflect the strength change due to the curing reactions. In addition to the experimental study, finite element analyses were performed on several types of disc models under various loading conditions. As a result, a comparison between all loading conditions was made to determine the best ITSs of the cemented paste backfill materials. Both experimental and numerical analyses concluded that loading arcs with definite contact angles gives better results than those obtained with the other loading apparatus without a definite contact angle. Loading arcs with the contact angle of $15^{\circ}$ was found the most convenient loading apparatus for the typical cemented paste backfill materials, although it should be used carefully considering the failure cracks for a valid test.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.294-297
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• 2006

The rail clamp is the device to prevent the crane slips along a rail from the wind blast as well as to locate a container crane in the set position during an operating mode. In this study we conduct the research for determining the proper position of supporter to prevent the overload applied to the rail clamp with respect to the wedge angle in the wedge type rail clamp. The friction force between the jaw pad and the rail to prevent that the crane slips along a rail, when the wind blows, is generated fly the rail-directional wind load. Accordingly the proper position of the supporter to prevent the overload is determined fly analyzing the forces applied to the rail clamp in the wedge working stage. In order to analyze the effect of the wedge angle on the position of supporter, 5-kinds of wedge angles, such as 2, 4, 6, 8, $10^{\circ}$, were adapted as the design parameter, and the wind speed of 40m/s was adapted as the design wind speed criteria.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권4호
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• pp.229-239
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• 2009

The purpose of this study is to evaluate the change in condylar position, width, and angle before and after orthognathic surgery using 3-dimensional computed tomograph. Pre and posterative 3-D CT was taken on 38 patients and through axial, frontal, sagittal measurements and by 3-dimensional reconstruction, the changes in condylar postion, mandibular width and angle were analyzed and others such as the difference in gender, operation and fixation method, setback length and in relation with temporomandibular disorders were done together too. The results were as follows: The inward rotation of condyle in axial condylar angle, the forward movement of right condyle in sagittal anterior-posterior distance, the superior movement of both condyles in sagittal superior-inferior distance, the decrease in gonial angle, the increase in mandibular width, the decrease in distance between the axial coronoid process distance and the increase in the frontal intercondylar distance were statistically significant. There were no statistically significant changes in gender difference, however in the difference in operation method, change in the gonial angle was observed and there was more change in bilateral sagittal split osteotomy group compared to two-jaw surgery group. In the difference in fixation method, the decrease in axial coronoid process distance and the change in sagittal anterior-posterior distance were statistically significant. In the difference in setback, the increase in setback didn't relate directly with the increased change in condyle position. In the relation with temporomandibular disorder, changes in left axial condylar angle and axial coronoid process distance were statistically significant. Changes in condylar position could be observed after the orthognathic surgery but it doesn't seem to have much of a clinical importance. The orthognathic surgery is effective in decreasing the mandibular angle, and it is not related with the temporomandibular disorder.

• 대한치과교정학회지
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• 제28권2호
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• pp.237-253
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• 1998

골격성 제 III급 부정교합 환자에서 성장조절이나 절충치료로 해결하기 어려운 경우 악교정 수술을 시행하게 되며, 이러한 환자의 대부분이 최대의 효과를 얻기 위해 상하악 동시 수술이 필요하다. 이러한 양악 수술에서, 교합평면의 설정은 진단 및 치료에 매우 중요한 기준이 되어지며, 바람직한 기능 및 심미적인 결과와 술후 안정성을 얻을수 있도록 계획되어져야 한다. 본 연구에서는 양악 수술을 시행받은 골격성 제 III급 부정교합 환자 48명 (남자25명 여자23명, 평균 연령 21.5세)을 대상으로 하여 교합평면의 설정에 사용되어지는 몇가지 진단 기준중, 많이 사용되어지고 있는 Delaire의 구조적, 구성적 분석에 의한 각 개인의 이상적인 교합평면의 술후 안정성에 대해서 평가하고자 이상적인 교합평면에 부합되게 수술이 시행된 군(A군-24명)과 이 평면에서 벗어난 군(B군-24명)으로 나누어, 수술 직전($T_1$)과 수술 직후($T_2$-평균 4.3일), 수술 8개월 이상 경과 후($T_3$-평균 1년 3개월)에 두군의 측모 두부 방사선 사진을 비교하여 다음과 같은 결론을 내렸다. 1. 양악 수술 후 $T_2와\;T_3$시기의 유의차를 보인 값은 교합평면과 하악평면이 이루는 각 이었으며 그외의 교합평면의 경사도에선 유의성 있는 차이를 보이지 않았다. 즉 교합평면의 술후 재발량은 SN평면과, FH평면에 대해서 각각 $0.24^{\circ}{\pm}2.43{\circ},\;0.15{\circ}{\pm}2.16{\circ}$로 양악 수술 후 교합평면의 안정성은 유지되었다. 2. A군과 B군사이에서 교합평면의 안정성에는 유의성 있는 차이가 없었다. 3. A군및 B군내에서 교합평면의 안정성은 술자 및 수술방법에 따라 유의성 있는 차이를 보이지 않았다. 4.술후 교합평면의 변화($T_3-T_2$)는 술후의 치아에 의한 변화 보다는 악골의 변화($T_3-T_2$)와 높은 순상관관계를 보였으며 특히 하악골의 변화와 높은 순상관관계를 보였다. 5. 술후 교합평면의 변화($T_3-T_2$)는 수술에 의한 상악골의 impaction양, 하악골의 후퇴량($T_2-T_1$)과는 상관관계를 보이지 않았다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1605-1608
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• 2006

The contrast ratio, brightness, and uniformity of S-IPS panel, whose alignment process was employed by ion-beam-alignment (IBA) technology, were improved significantly compared with the convention rubbing's panel, because the light leakage has been reduced in dark state effectively. The IBA technology could generate a panel whose pretilt angle was stable and low after post-treatment process.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제41권3호
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• pp.145-148
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• 2015

In 1942 Stafne reported 35 asymptomatic, radiolucent cavities that were unilaterally located in the posterior region of the mandible between the mandibular angle and the third molar, and below the mandibular canal. The term Stafne bone cavity (SBC) is now used for such asymptomatic lingual bone depressions of the lower jaw. Since then there have been many reports of SBCs but very fews tudies have used cone-beam computed tomography (CBCT) for their diagnosis. The aim of this paper is to describe the clinical and radiological characteristics of two cases of SBCs and the importance of limited CBCT in confirming the diagnosis.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1-6
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• 2003

In this paper, we design a wedge type rail clamp which can protect container crane from wind with constant clamping force regardless of the operating period. When we design wedge type rail clamp. it is important to determine the angle of wedge and analyze a contact condition of roller and wedge so that we might develop a rail clamp with variable capacity. Therefore, this paper suggest a process to decide wedge angles within feasible range which could be obtained using load analysis and FEA of wedge type rail clamp.

• Imaging Science in Dentistry
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• 제38권2호
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• pp.109-115
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• 2008

The basal cell nevus syndrome (BCNS) is an autosomal dominant disorder, characterized by basal cell carcinomas, odontogenic keratocysts and skeletal abnormalities. We experienced two cases that represented several characteristics of BCNS. Case 1: a thirty three year-old man visited CSU hospital. His radiographs showed four cystic lesions at both maxillary sinus and both mandibular angle, with bifid rib and ectopic calcification of falx cerebri. After marsupialization and enucleation, recurrent and newly developing tendency were found on his follow-up radiographs. Case 2: a seventeen year-old man had four large cystic lesions which were diagnosed as odontogenic keratocysts. He had craniofacial anomalies which included ectopic calcification and frontal bossing.

• 대한두경부종양학회지
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• 제34권1호
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• pp.29-32
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• 2018

The parathyroid glands are usually located in the posterolateral area of the thyroid gland. Due to their embryologic origin, they are sometimes found in an ectopic position from the angle of the jaw to the mediastinum. However, their incidental detection in the hypopharyngeal wall is rare. Herein, we report a case of an ectopic parathyroid gland found in the hypopharyngeal wall of a 39-year old woman with no known endocrine abnormality.