• 대한치과교정학회지
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• 제41권5호
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• pp.371-378
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• 2011

Transposition is defined as a dental anomaly manifested by a positional interchange of 2 adjacent teeth within the same quadrant of the dental arch. Maxillary canine-first premolar [Mx4-3] transposition is the most frequent tooth transposition reported in the literature. In this case report, an orthodontic correction of a transposition of the maxillary left canine and first premolar with the help of palatally located mini-implant anchorage is described. Esthetic and occlusal evaluations suggested alignment of the transposed teeth to their correct anatomic positions in the dental arch. The clinical result at the end of the treatment was satisfactory. Alignment was obtained, and intercuspation was adequate. Nevertheless, the maxillary canine showed facial recession, probably because it was initially positioned buccally. Supporting tissue was examined after treatment and no alveolar bone damage was observed.

• International Journal of Precision Engineering and Manufacturing
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• 제2권4호
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• pp.5-11
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• 2001

Vibration and noise of gears is doc to the transmission error and the vibration exciting force caused by the periodically alternating tooth stiffness. Transmission error is the rotation delay between driving and driven gear caused by manufacturing error, alignment error in assembly and so on. Tooth stiffness changes with the proceeding mesh of teeth. The purpose of this study is to develop how to calculate simultaneously the optimum amounts of tooth profile modification. end relief and crowning by minimizing the vibration exciting force of helical gears. We estimate the vibration exciting force by the meshing analysis of gears. Formulated constraints of this problem consist of contact ratio and strengths of gear teeth such as tooth bending strength, surface durability, and scoring. ADS(Automated Design Synthesis) is used as an optimization tool. We also investigate the relation between the aspect ratio and the optimum values of tooth modification. The proposed method can calculate the optimum amount of tooth modification automatically and is expected to be practically useful to resolve the problem of vibration of helical gears.

• 한국정밀공학회지
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• 제17권11호
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• pp.199-205
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• 2000

The vibration and noise of gears is due to the vibration exciting force caused by the tooth stiffness which changes periodically as the mesh of teeth proceeds and by the transmission error, that is, the rotation delay between driving gear and driven gear caused by manufacturing error and alignment error in assembly and so on. The purpose of this study is to develop how to calculate simultaneously the optimum amounts of tooth profile modification, end relief and crowning by minimizing the vibration exciting force of helical gears. We estimate the vibration exciting force by the mesh analysis of gears. The constraints of this problem consist of contact ratio and strengths of gear teeth such as tooth fillet stress, surface durability and scoring. ADS(Automated Design Synthesis) is used as an optimization tool. And, since the aspect ratio is an important parameter of tooth modification, we investigate the relation between it and the optimum values of tooth modification. The proposed method can calculate the optimum amount of tooth modification automatically and is to be utilized to resolve the problem of vibration of helical gears.

• 대한소아치과학회지
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• 제26권1호
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• pp.38-43
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• 1999

치아전위는 비교적 드문 발육장애이다. 적절하게 차단치료된다면 예방이 가능할 뿐 아니라 이후의 교정과 수복과정이 보다 용이할 수 있다. 이를 위한 8-9세 경의 조기 임상검사가 이러한 발육장애의 인지를 위해 추천된다. 일단 전위가 일어난 경우에는, 부정교합을 교정하고 최상의 기능적, 심미적 결과를 얻기 위해 주의깊은 교정적 평가가 요구된다. 이상적인 결과를 얻기 위하여 두 치아를 원래의 위치로 환원시키는 치료가 요구되나, 완전전위되어 두 치아가 맹출되었다면 전위된 상태로 치아를 배열하여도 비교적 양호한 결과를 얻을 수 있었다.

• 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.

• 대한소아치과학회지
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• 제32권3호
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• pp.409-415
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• 2005

영구 전치의 매복은 제 3 대구치나 견치에 비해서 드물게 나타나지만 학령기 아동에서 관찰할 수 있다. 매복치아의 원인은 외상, 공간 부족, 치아의 맹출 경로상에 위치하는 과잉치, 유치의 치근단 감염 등 다양하다. 매복된 치아는 부정교합과 인접치아의 치근 흡수, 낭종 등의 병적 변화를 유발할 수 있으므로 임상적 검사와 방사선학적 검사를 통해 정확한 위치를 확인하고, 적절한 치료계획을 통해 정상 맹출을 유도하여야 한다. 매복된 치아가 병적 변화를 일으킨 경우나 인접치에 손상을 주었을 경우에 발치를 시행하게 된다. 그러나 교정적 견인을 통해 기능과 심미성을 회복시켜 줄 수 있으므로 조기 발견과 발견시의 올바른 진단과 치료 계획을 수립하는 것이 중요하다. 교정적 견인시에는 매복치를 배열할 공간의 확보와 고정원에 대한 고려가 선행되어야 한다. 견인시 적절한 방향의 힘을 통해서 치근의 흡수 등의 부작용이 일어나지 않도록 해야 한다. 본 증례는 매복된 전치들을 forced eruption을 통해서 정상적인 맹출 방향으로 유도한 치험례이다.

• 소성∙가공
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• 제32권6호
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• pp.376-383
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• 2023

The torsion bar, which is a steering torque sensor, is mounted between the steering pinion and the input shaft in the IPA(input pinion assembly). Accurate torque measurement is important to improve the sense of operation, and the straightness of the torsion bar can affect torque measurement. In this study, the amount of bending was measured and the exact shape was analyzed regarding the bending phenomenon in the press-fitting process for torsion bars. The effect of alignment error was analyzed through finite element forming analysis. Process data analysis was conducted for the double-end press fit model. If there is an alignment error of about 10% of the serration tooth height, the indentation load is reduced by about 10%. If there is an alignment error, the torsion bar is rotated.

• 대한치과의사협회지
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• 제54권2호
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• pp.134-141
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• 2016

Use of ready-made orthodontic appliance can lead to inefficiencies in the final stages of the orthodontic treatment. Because patients' teeth have anatomic variations, brackets that have been designed to fit on average tooth surface may result in positional discrepancies when leveling and alignment is completed. As a result, additional steps such as rebonding, wire bending and use of auxiliaries may be needed. Even in patients who have normal tooth anatomy and proper tooth size relationships, precise bracket placement is crucial in order to efficiently control the tooth positions. Digital models can provide advantages in clinical orthodontics as virtual tooth setup could be performed, and clinicians can easily visualize the predicted final occlusion. Through this setup model, customized brackets with individualized prescription and archwires that optimally fit with the patients' dental arches can be produced using CAD/CAM technology. Also, the brackets can be accurately placed with an aid of 3D-printed jigs. The purpose of this article is to introduce the commonly used labial and lingual customized orthodontic appliance systems using digital technology.

• 대한치과의사협회지
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• 제11권3호
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• pp.171-175
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• 1973

A 9-year-old girl, in good health, presented a horizontal impaction of the upper left central incisor. History revealed that the patient had been involved in a trauma of the maxillary anterior portion during her childhood. This impacted tooth crown, which was exposed surgically, was bonded by plastic attachments of direct bonding system, and was carefully tried to induce on the dental arch. On the process of the orthodontic treatment the tooth was completely induced and in normal alignment on the arch. The treatment result was very satisfactory; color, vitality, and mobility were normal, periodontal support was good and the cosmetic result was excellent.

• International Journal of Clinical Preventive Dentistry
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• 제14권4호
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• pp.209-215
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• 2018

In recent years, the numbers of the orthodontic dental patients have been rapidly increased in adolescent or young adult aged generation. It has been well known that it would be very hard to control the oral hygiene cares for orthodontic applied dental patient because of the complexity of the appliance. So the caries prevalence of the orthodontic dental patients would be higher than non-appliance persons, and it might be easy to cause the dental caries especially on the labial or buccal surface of the tooth through equipping the fixed type appliance with a long period, even though the alignment of the teeth would be arranged well. So, the massive preventive program for preventive dentistry should be needed for the dental patients for orthodontic treatment, in order to protect the dental caries and the periodontal disease for them. But, lots of the dentists or dental hygienists sometimes neglect of this point for preventive dental cares orthodontic dental patients, or do not know the importance and how to manage the skill for the preventive dental works in clinical. In this article, it will be introduced the basic theories and skills for preventive cares as tooth-brushing instruction, fluoride topical application and pit and fissure sealant, scaling and professional mechanical tooth cleansing and the diet control, for the dental patients with the fixed type of the orthodontic appliance, in case by case.