• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.490-497
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• 2007

Odontoma is defined as a benign odontogenic tumor containing enamel, dentin as well as cementum and constitued 22% of all odontogenic tumors. Although the lesions are commonly asymptomatic, they may be discovered routine radiographic examination. Odontomas often cause disturbances in the eruption of teeth such as, impaction or delayed eruption, retention of primary teeth, or abnomalities in the position of the teeth such as tipping or displacement of adjacent teeth. Radiologically, odontomas manifest as a dense radiopaque lesion surrounded by a thin radiotransparent halo. However, in some cases, radiopacity was not quite clear and images of the teeth shadowed very tiny odontomas. And at early development stages of odontoma, calcification remains immature and is difficult to diagnose on radiographs. This suggests that when delayed eruption of the teeth is found, periapical radiographs should be taken to clarify whether any small area of radiopaque material exists. This case report shows tiny odontomas involving an impacted tooth and crowding and we remove the tiny odontoma surgically.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.532-536
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• 2010

Hidden caries is a subtype of the occlusal pit and fissure caries type and is defined as a dentinal caries lesion near the occlusal surface of the tooth seen on a radiograph. In visual examination, the occlusal enamel is seen intact or is minimally perforated. Covert caries, Occlult caries or Fluoride syndrome are used as synonym. The percentage of occlusal dentin lesions that are clinically undetected ranges from 1.4-50%. Little is known about the mechanisms involved in the development of hidden caries. But it is thought that extensive use of topical fluoride or the special bacteriological profile has been a major factor. This case report is about detection and treatment of hidden caries of two children who visited the department of pediatric dentistry, Yonsei University Dental Hospital. The color of caries dentin found in hidden caries lesion is lighter than cavity forming caries, which makes it more difficult to detect caries by visual examination. Therefore diagnosis of hidden caries is often accomplished after clinical sign is recognized by patients. The use of advanced caries detection aids such as Diagnodent.. with periodic radiographic examination is seemed to be helpful for early detection of hidden caries.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.143-152
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• 2023

Although tooth wear is a normal process due to aging, severe tooth wear causes various complications such as increased tooth sensitivity, loss of tooth structure, and pulp complications. In the treatment of patients with excessive tooth wear, the evaluation of loss of vertical occlusal dimension should be prioritized. If it is necessary to increase the vertical dimension to secure the restoration space, it is important to establish a treatment plan with the comprehensive analysis and determine the minimum vertical dimension elevation. In this case, 66-year-old male patient with severe worn dentition wanted to restore masticatory function and improve esthetic restoration. In order to determine the appropriate vertical dimension of the patient, we evaluated oral examination, radiographic examination, and diagnostic cast examination, and performed rehabilitation with minimum vertical dimension elevation. As a result of observation for 8 months, the definitive prosthesis was completed with contact of all teeth in centric occlusion, and proper anterior/posterior guidance. Through the above process, satisfactory aesthetic and functional outcomes were obtained.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.482-489
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• 2020

This study conducted a prototype development and evaluation by performing die-casting mold design, mold manufacturing, and injection condition optimization based on flow and solidification analysis to meet the needs of the coupling parts produced by die casting. Through flow analysis, the injection conditions suitable for 100% filling in the cavity were found to be a molten metal temperature of 670 ℃, injection speed of 1.164 m/s, and filling pressure of 6.324~18.77 MPa. In addition, solidification close to 100 % occurred in all four cavities when the solidification rate was 69.47 %. A defect inspection on the surface and inside the product revealed defects, such as poor molding and pores. In addition, the dimensions of the injected product were within the target tolerance and showed good results. Through the feedback of the results of flow and solidification analysis, it was possible to optimize the mold design, and the injection optimization conditions were confirmed to be a total cycle time of approximately 6.5 seconds. Good quality carrier parts with an average surface hardness of approximately 45 mm from the gate measured at 97.48(Hv) could be produced.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.465-473
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• 2005

The purpose of this study was to evaluate the desensitizing effects of a Nd:YAG laser (Sunlase, SUNRISE Technologies, Inc., USA) irradiation on cervically exposed hypersensitive dentine. 45 patients was irradiated with pulsed Nd:YAG laser (1.5 W, 20 Hz, 75 mJ/pulse, 4 minutes) as the experimental group, 27 patients was mock irradiated as the control group. The degree of sensitivity to the thermal and tactile stimuli were determined qualitatively with an evaporative stimulus defined as two times air blast at a distance of 3 mm from each site to be tested and with a mechanical stimulus as a slightly scratching the cervical site with a dental explorer. A qualitative registration of the degree of discomfort was determined according to a numerical pain scale(NPS) in an 11-point scale in which 0= "no pain" and 10="most excruciating pain imaginable". Recordings were assessed before treatment, immediately after, 1 and 2 weeks after treatment. Pain tolerance threshold and pulp vitality were evaluated with electric pulp tester before and immediately after treatment. 1. Desensitizing of hypersensitive dentine with Nd:YAG laser irradiation was more effective than that with mock irradiation. 2. The placebo effect of mock irradiation was recognized for severe sensitive teeth($NPS\;{\geqq}\;6$), but not for moderate sensitive teeth(NPS < 6). 3. Laser irradiation did not affect the pain tolerance threshold and pulp vitality of the hypersensitive teeth. 4. Desensitizing effect of laser irradiation for the hypersensitive teeth had been continuing at least 2 weeks. It was concluded that desensitizing of hypersensitive dentine with a Nd:YAG laser is effective and the maintenance of the positive result was more prolonged than the placebo effect.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.454-460
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• 2007

Traumatic dental injuries in childhood and adolescent occurred more frequently than in adult. The time between the accident and the treatment is one of the most critical factors to prognosis, and because of the limited time available to examine and treat patients with traumatic dental injuries, if not treat appropriately, the result would be critical for the patient. In the previous studies, the prevalence and incidence of traumatic injuries were the most frequent at the age of 8 to 10 years, the majority of dental injuries involve the anterior teeth, especially the maxillary incisors, and males were more prevalent than females in an approximated proportion of 2:1. As the mean age of complete root formation is 10 years old, the maxillary permanent incisor involved in the most affected age group is usually immature, and the possibility of pulpal healing through excellent revascularization exists, more positive prognosis for pulp vitality would be expected. These are treatment cases of the immature maxillary permanent central incisor involved in the traumatic injury, and reports for progress and results of preserving the pulp vitality through the conservative treatment instead of the conventional endodontic root therapy.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.323-328
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• 2006

Dentinogenesis imperfecta is an inheritable disease of dentinal defect, generally is inherited as a single autosomal dominant trait. It has a prevalence of 1 in 8000 with the trait, and no significant difference between male and female, with involvement of the primary and permanent teeth. Shields proposed three types of Dentinogenesis imperfecta. Affected teeth have various discoloration, separation of enamel rapid destruction of underlying dentin, and severe attrition. Radiographically, the teeth have cervical constriction, bulbous crown, thin root, obliteration of the root canals and pulp chambers, and periapical lesions in a sound tooth. The objective of treatment is rehabilitation of the esthetics, the masticatory function, and the vertical dimension of occlusion. In these cases, two pediatric patients reported to the Kyungpook University Pediatric clinic, with a chief complaint of discolored teeth and severe attrition. As a result of clinical and radiographic exam, it was diagnosed as Dentinogenesis imperfecta. The posterior teeth were restored with Stainless Steel Crown, and the anterior teeth were restored with composite resin veneering.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.3_4
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• pp.390-401
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• 2002

This study was to evaluate the fitness and the suitability of size specification of the ready made jacket for women by analysing pattern size and space between skin and clothing using 3D scanner. The results were as follows: 1. Pattern B had the lowest score and the feeling of wearing was significantly different among the given patterns even though all jacket size specification were the same. 2. Ease amount was different between each brand even though the jacket size specification was the same due to the different pattern grading rules. And increasing grading amounts were bigger in horizontal direction rather than in vertical direction. 3. We could obtain accurate a 3 dimensional figure, using 3D scanner which was very useful and more accurate than 2 dimensional data using photography method. 4. Analyzing the average space between skin and clothing of each pattern, there was no significant difference in the average space between skin and clothing among all patterns except waist part of B88 size. And analyzing the average space between skin and clothing of each measured body parts by each size, there existed a significant difference in the interscye, abdomen and hip parts.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.401-409
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• 2016

This research investigates into overall oral health status of adolescent girl inmates in a juvenile detention facility and ordinary school students in the same age range of 11 to 18 years old and compares the results focusing on the difference between the two groups. The last 5 years dental records for girl inmates in Juvenile detention facility and for students who have visited the Department of Pediatric Dentistry at Ajou University Hospital was colleted and analyzed. The restorative treatments took up the greatest part in their history of treatments. While the percentage of extractions of permanent teeth due to dental caries had been gradually increased, in Juvenile detention facility students, throughout the transition period from middle school to high school, in dental hospital patients, the phenomenon of the same kind has hardly been detected. After that record analysis, oral examination for Juvenile detention facility students and dental hospital patients was conducted. DMFT index for dental hospital patients are 4.15, whereas, the value for Juvenile detention facility students are as twice as high to be 7.53.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.151-151
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• 2017

본 연구는 인력을 이용한 품질검사를 수행하고 있는 현장에서 불량 및 품질에 대한 신뢰성이 떨어지고 있는 현상을 해소하기 위해 자동으로 평면도를 측정하고자 하였다. 설계는 Auto CAD를 이용하였다. 평면도 측정기의 크기는 가로${\times}$세로${\times}$높이를 $1000{\times}600{\times}1800mm$로 하였다. 프레임은 $60{\times}60$ 프로파일을 이용하였고 다른 구성 부품은 SUS304 재질을 이용하였다. 측정대상을 올려놓은 상태에서 녹색 버튼을 누루면 작동되도록 되어 있다. 그림 8은 측정결과를 나타낸 것이다. 측정기는 국내업체인 데바의 모델명 EA-20N의 Air Micrometer을 사용하였으며 측정핀의 위치는 조정이 가능하도록 하였다. 평면도 측정 중 설정치수와 같이 않으면 NG 명령과 함께 부저가 울리도록 프로그램하였다. 불량이 발생하면 그림 8과 같이 나타났다. 불량 측정을 위해 측정부의 결과 값이 나타나며 불량이 발생하면 어느 위치에서 불량이 발생했는지를 알 수 있도록 하였다. 또한 결과 값은 자동으로 저장되도록 하였다. 품질확보를 위해 100EA를 측정한 결과 0.00258, 0.00259, 0.00259, 0.00263, 0.00251, 0.00286, 0.00275의 평균값을 나타냈다. 측정값의 검증은 하이트게이지로 측정한 결과 0.002 이내의 결과를 나타냈다. 따라서 본 평면도 측정기를 이용한다면 생산성 향상이 가능하여 가격경쟁력이 있다고 판단된다.