• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.27-32
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• 2022

There has always been a demand for orthodontic treatment. Orthodontic treatment allows tooth to be arranged by flexible arch wire fixed with tooth-attached brackets. Arch wire generate constant pressure to tooth brackets which moves the teeth to proper place. When the bracket transmits force, the braced wing of the bracket may deform. Deformed tie wing will lead to lost tension of elastic ligature. Then, lacking grip between tie wing and ligature might delay the tooth movement. Furthermore, tooth brackets used for orthodontic treatment make contact with in direct oral surface and this cause feeling of irritation that comes from height of tooth braces. This study suggests an optimal teethe bracket design to make up for inconvenience by shorten the height of bracket and complement the shape of bracket to reduce strain rate using finite element analysis. As a result, new optimal design of teethe bracket indicates lower strain rate of the bracket wing and takes good effects of shorten body height in terms of convenience.

• 대한소아치과학회지
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• 제38권1호
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• pp.51-55
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• 2011

과잉치는 영구치열 및 유치열에서 발생하는 치아 발육 장애이다. 원인은 명확하게 밝혀지지 않았으나 치판의 과도한 활성으로 인해 발생한다는 이론과 환경적 요인으로 인해 치배가 두 개로 나눠진다는 이론 등이 제시되었다. 과잉치의 발생은 유치열보다는 영구치열에 호발하며 전상악부에 높은 빈도로 발생한다. 과잉치가 발생한 위치나 형태에 따라 분류할 수 있으며 정상적인 형태를 나타날 때 보충치(supplemental tooth)라고 명명하기도 한다. 과잉치 발생시 치아의 맹출 장애, 총생, 정중이개, 인접치의 회전이나 흡수, 낭종 등의 합병증을 야기할 수 있으므로 조기 발견 및 진단이 중요하다. 과잉치의 처치는 형태나 위치, 치열에 미치는 영향 그리고 환아의 심리적 상태 등을 고려하여야 한다. 본 증례에서는 방사선학적 검사와 임상 검사를 통해 상악의 과잉 유구치를 진단하였다. 하지만 어떤 치아가 과잉치인지 진단하기가 어려웠다. 적절한 공간 형성과 과도한 공간 소실을 방지하기 위하여 악궁의 근심에 위치한 치아를 발거하여 양호한 결과를 얻었다.

• Journal of Periodontal and Implant Science
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• 제36권4호
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• pp.817-827
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• 2006

Purpose : This study was designed 1) to compare the perception of dental professionals and lay people with respect to minor variations in maxillary anterior tooth size and alignment and their relation to the surrounding soft tissues, and 2) to evaluate the normal tooth-gingiva topographical relationships in periodontally healthy young subjects, Materials and methods : Maxillary anterior teeth were intentionally diagrammed in varying degree of deviation with respect to one of three common anterior esthetic discrepancies including variations in crown length, shape of gingival margin, and length of interproximal contact, 17 images were generated to be preferentially selected by 2 groups consisting of dental professionals and lay people (total of 740). Smiling photographs of 120 dental students who had healthy periodontium were taken and the photographic images were analyzed to be classified as 17 kinds of altered image groups. Results : The results demonstrated noticeable difference between the varying levels of discrepancy. Both group preferred gingival margin of lateral incisor to be 0.5mm lower than that of central incisor. Lay people preferred the gingival margin shape that has 2/9 horizontal component of the crown width, while dental professionals preferred the gingival margin shape that has 1/9 horizontal component of the crown width. Lay people preferred longer length of the interproximal contact (two thirds of the crown length), whereas dental professionals preferred shorter length of the interproximal contact (half of the crown length). Photographic analysis of normal esthetic gingival topography revealed 2/9 horizontal component and short length of the interproximal contact which was of the hybrid nature of the preferences shared by lay people and dental professionals. Conclusion: The results of this study show that dental professionals and lay people demonstrated significant difference in their preference of dental esthetic components, which may then influence the decision making process by dental professionals with respect to designing the anterior esthetic gingival line.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.220-225
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• 2014

A fiber-reinforced composite (FRC) fixed prosthesis is an innovative alternative to a traditional metal restoration, as it is a conservative treatment method. This case report demonstrates a detailed procedure for restoring a missing anterior tooth with an FRC. A 44-year-old woman visited our department with an avulsed tooth that had fallen out on the previous day and was completely dry. This tooth was replanted, but it failed after one year. A semi-direct technique was used to fabricate a FRC fixed partial prosthesis for its replacement. The FRC framework and the pontic were fabricated using a duplicated cast model and nanofilled composite resin. Later on, interproximal contact, tooth shape, and shade were adjusted at chairside. This technique not only enables the clinician to replace a missing tooth immediately after extraction for minimizing esthetic problems, but it also decreases both tooth reduction and cost.

• 대한치과의사협회지
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• 제56권6호
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• pp.314-322
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• 2018

Among developmental anomalies of tooth shape, fusion and gemination are comparatively common. Developed with different etiologies, both fusion and gemination show similar clinical features. Therefore, many clinicians have difficulty diagnosing those morpho-anatomic anomalies. The purpose of this study is to report malformed right maxillary first molar in a 20-year-old female. With the aid of computed tomography (CT), the tooth was diagnosed as fusion with supernumerary tooth and dental caries lesion was detected. After performing direct pulp capping, the tooth was permanently restored with microhybrid composite resin using direct method to alter union groove into smooth surface for improving oral hygiene management. Until 6 months of follow-up visits, patient's chief complaint was resolved and tooth is still vital. In conclusion, identifying exact anatomy, conservative treatment and improving oral hygiene are essential in managing unusual morphologic anomalies of tooth.

• 대한치과교정학회지
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• 제47권6호
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• pp.384-393
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• 2017

Fusion of teeth is a developmental anomaly. It occurs at the stage of tooth formation, which determines the shape and size of the tooth crown, when one or more teeth fuse at the dentin level during the morphodifferentiation of the dental germs. Such teeth show macrodontia and may cause crowding, as well as esthetic and endodontic problems. In this article, we report a rare case of a maxillary central incisor fused to a supernumerary tooth showing labial and palatal talon cusps, which was orthodontically moved across the midpalatal suture. A 13-year-old Caucasian boy sought treatment for the unesthetic appearance of his maxillary central incisor and anterior crowding. He was rehabilitated successfully via a multidisciplinary approach involving orthodontic, nonsurgical endodontic, periodontal, and prosthodontic treatments. After a 26-month treatment period, the patient's macroesthetics and microesthetics were improved. The overall improvement of this macrodontic tooth and its surrounding tissues through multidisciplinary treatment was documented using cone-beam computed tomography.

• 대한전자공학회논문지SP
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• 제41권3호
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• pp.163-174
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• 2004

치과 분야에서는 치아교정이나 수술 시뮬레이션을 위해서 각 치아를 개별적으로 조작할 수 있는 3차원 치아모델이 필요하다. 치아 CT 영상으로부터 이러한 치아모델의 재구성을 위해서는 각 치아를 이웃한 치아나 치조골로부터 정확하게 분리할 수 있어야 한다. 본 연구에서는 치아 영역을 효과적으로 분리하기 위한 영상정규화 방안과 최적임계화방안을 제안한다. 제안된 방법은 연속적인 CT 영상 슬라이스들에서 치아영역의 형태와 밝기는 점진적으로 변한다는 사실을 근거로 이전 슬라이스에서 추정된 임계치를 이용하여 현 슬라이스의 임시치아경계를 결정하고 이것을 바탕으로 보다 정확한 임계치를 계산한다.

• Applied Microscopy
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• 제38권4호
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• pp.375-382
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• 2008

삼차신경주감각핵에서 치수유래 일차들신경섬유의 종말과 그에 연접하는 연접이전신경종말에 함유된 연접소포들을 형태학적으로 비교하기 위하여 신경추적자(WGA-HRP)를 흰쥐 앞니의 치수강에 주입하여 치수 유래 일차들신경종말을 표식한 후, 투과형 전자현미경을 통한 미세구조적 정량 분석을 실시하였다. 표식된 치수유래 일차들신경종말은 직경이 $45{\sim}55\;nm$인 구형의 소포를 함유하고 있었으며, 일부 직경이 $80{\sim}120\;nm$ 큰 치밀소포가 관찰되기도 하였다. 또한 표식된 신경종말은 다형성 연접소포를 함유하고 있는 연접이전신경종말과 대칭연접을 이루고 있었다. 일차들신경종말의 연접소포들은 긴 지름에 대한 짧은 지름의 비율(form factor)이 $0.6{\sim}0.99$의 분포를 보인 반면, 연접이 전신경종말의 연접소포들은 $0.25{\sim}0.99$까지 다양하게 나타났다. 또한 대부분의 연접이전신경종말은 GABA에 대한 면역양성반응을 보였다. 이상의 결과는 표식된 신경종말과 그에 연접하는 연접이전신경종말의 연접소포는 서로 다른 형태를 보이고 있으며, 또한 그 연접이전신경종말이 억제성 신경전달물질인 GABA를 함유하고 있음을 나타낸다.

• 한국정밀공학회지
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• 제23권6호
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• pp.44-51
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• 2006

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product for the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.769-772
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• 2005

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product fur the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.