• 한국융합학회논문지
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• 제2권2호
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• pp.27-34
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• 2011

본 연구는 호빙 가공공정 없이 워엄 휠 기어 형상을 만들기 위한 워엄 휠의 개발을 위한 제품을 만드는 것이다. 호빙 가공 공정이 없기 때문에, 증가된 생산성과 등가의 품질을 가지는 플라스틱 워엄 휠이 결국 만들어지게 된다. 그 결과, 이 제품은 현대 모비스, 만도, TRW, KOYO/NSK/Showa(Japan), Delphai(Amercia)에 판매 될 것이다. 핵심 기술 및 전략은 다음과 같다. 워엄 휠의 성형을 위한 기술 보호는 최근 "헬리컬 기어(No. 10-2008-0105908) 성형"이 특허 공정으로 되어 있다. 나아가, "보스 삽입을 위한 위치 결정을 위한 성형 시스템"을 위한 특허 절차가 준비 중이다. 기어 기계가공 절차 없이 호빙 머신에 기어 성형 절차로서, 무엇보다 먼저, 기어를 만드는 코어 개발 기술이 주된 주제이다. 따라서, 코어 및 성형 기초가 초기 순서로 개발되지 않아서, 현재 개발되는 워엄 휠의 경우, 기어는 이차적으로 호빙 M/C로 기계가공 된다. 최종적으로는, 성형 기초 구조체를 위한 특허가 본 연구결과로 만들어질 예정이다.

• 대한기계학회논문집A
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• 제36권4호
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• pp.387-393
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• 2012

본 논문에서는 기존 랙-피니언 시스템의 랙 치형을 핀 또는 롤러로 대체한 롤러 랙 피니언 (RRP) 시스템의 표면피로 향상방안을 고찰하였다. 우선 전위계수(profile shift coefficient)를 고려하여 RRP 시스템의 캠 피니언(cam pinion)에 대한 엄밀 치형설계 방법 및 언더컷 방지 조건을 소개하였고, 이를 바탕으로 설계인자의 변화에 따른 하중 및 하중응력계수(load stress factor)의 변화를 검토하였다. 이를 통해 RRP 시스템의 표면 내구성을 향상시킬 수 있는 방안으로 전위계수의 증가가 효과적임을 알 수 있었다.

• 대한소아치과학회지
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• 제32권4호
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• pp.682-686
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• 2005

색소실조증(Incontinentia pigmenti)은 신생아기에 체간과 사지에 소수포가 발생하여 1세경이 되면 수포는 더 이상 생기지 않고 갈색반점이 나타나는 특징을 보이는 아주 드문 질환이다. Bloch-Sulzberger syndrome이라고 불리는 이 질환은 반성 우성 유전질환으로 대부분 여성에게 나타나며, 외배엽, 중배엽 기원 조직들인 눈, 치아, 피부, 손톱, 가슴, 머리카락, 신경계 등에 이상을 동반한다. 본 증례는 유치의 선천적 결손을 주소로 내원한 환아의 문진 중 색소실조증의 사실을 발견하고 검사한 결과, 다수의 유치와 영구치의 선천적 결손과 치아의 형태이상, 상악의 열성장, 치아의 형태이상과 악골 성장의 부조화 등으로 인한 교합불안정을 보이고 있었다. 전신적으로는 망막이상을 보여 수술을 시행한 상태이며, 피부에는 특징적 인 갈색반점을 보였다. 현재 치아결손부의 공간관리와, 심미적, 심리적인 문제의 해결, 그리고 기능의 회복을 위해 가철식 부분의치를 장착해주었으며, 계속적인 관찰을 하고 있다.

• 동아시아식생활학회지
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• 제15권4호
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• pp.373-385
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• 2005

This study was carried out to investigate the lactation and weaning practice of infants and their mothers' attitude on infant nutrition. We interviewed 152 mothers in three pediatric clinics located in Sokcho city. From this survey, $76.3\%$ of infants was fed colostrum milk during first one week of life. During the first 4 months, $31.6\%$ of infants was fed breast-milk, while $42.8\%$ of them was fed bottled-milk. More housewives fed their babies with breast milk than the working mothers. Infants ate first weaning food at 5.73$\pm$1.86 months of life. Highly educated mothers showed positive response to the questionnaire : Breast-feeding is good for baby but it requires mother's sacrifice, and Breast-feeding may ruin the good shape of mothers. Highly income mothers responded negatively to the statement : Breast-feeding is not a must for infants since bottled-milk is a good substitution for breast-milk. Comparing with the mothers whose income was about 1 -2 million won per month, with ones who got paid less than 1 million won per month the former responded positively to : Breast-feeding is good for baby but it requires mother's sacrifice. Mothers recognized the importance of weaning in the following order : Supply of nutrition, Enforcement of digestion and absorption capability, Variety of taste, Disease prevention, Development of self-reliance, and Development of baby tooth. To improve the infants' nutritional status, education program on infant nutrition should be organized and run for the pregnant and lactating women in obstetrician and pediatric clinics and through the mass media as well.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.519-535
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• 1997

The responses of human pulp fibroblastic cells to Ga-As Semi-Conductor-Dens-Bio Laser (Frequency: 5 Hz~10,000 Hz Model: SD-101A RCA, U.SA)) were examined in vitro using pulp fibroblastic cells obtained from the pulp tissue of human tooth. The mitogenic effect of soft laser was assessed by measuring the MTT assay. The morphologic effect for soft laser showed under the scanning and transmission electron microscopy. The results as follows; 1. The mitogenic response of the soft laser was not observed until 4th time of radiation, while the mitogenic response at 4th time increased mitogenic effect by as much as 1.7 fold compared to the control value. 2. The mitogenic response of the soft laser on pulp fibroblast differ from the mitogenic response on other fibroblasts. 3. In scanning electron microscopic study, The microvilli of cell surface increased gradually with width and length after laser radiation, it demonstrate that development of microvilli have close connection with differentiation of cells. 4. Under the transmission electron microscope, The laser-treated cells maintained their elongated shape and a high degree of cellular polarization. The large cell body containing a well developed Golgi complex, a large number of profiles of rough endoplasmic reticulum, and great numbers of mitochondria. 5. The laser-treated cells maintained the long straight bundles of closely apposed microfilaments or individual filaments forming a cross-linked network. These findings suggest that the laser may have important roles in promotion of pulp healing and consequently may be useful for clinical application in pulp regenerative procedures.

• Journal of Periodontal and Implant Science
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• 제34권3호
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• pp.647-657
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• 2004

A non-carious cervical lesion(NCCL) is the loss of tooth structure at the cementoenamel junction level that is unrelated to dental caries. This study was to evaluate the occlusal and periodontal status of teeth with non-carious cervical lesions. We evaluated 105 teeth with non-carious cervical lesions in 35 subjects aged 38-75 years and characterized them based on the shape and dimension, plaque retention, bleeding on probing(BOP), probing pocket depth(PPD), occlusal status, brushing type, hypersensitivity and wear facet. The results of this study were as follows 1. No significant association was observed between cervical lesions and occlusal contact in lateral excursions. 2. No significant difference occurred in plaque retention, PPD, BOP between teeth with and without cervical lesions. 3. Test teeth had a significantly higher percentage of hypersensitivity and occlusal wear facet than teeth without cervical lesions. 4. Wedge shaped lesions had a significantly higher percentage of plaque than saucer shaped lesions. 5. Teeth with plaque were found to have significantly deeper PPD than teeth without plaque retention in cervical regions. 6. Teeth with occlusal contacts were found to have significantly deeper PPD than teeth without occlusal contacts. 7. No significant association was observed between cervical lesions and PPD independent of plaque retention and occlusal contacts Although more knowledge is necessary, our results suggest that occlusal contact and bacterial plaque may influence on periodontal tissue, but NCCL is not directly associated with periodontal health

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.431-436
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• 2015

PURPOSE. The aim of this study was to evaluate occlusal contacts generated by 3 different biogeneric design modes (individual (BI), copy (BC), reference (BR)) of CEREC software and to assess the designs subjectively. MATERIALS AND METHODS. Ten pairs of maxillary and mandibular casts were obtained from full dentate individuals. Gypsum cast contacts were quantified with articulating paper and digital impressions were taken. Then, all ceramic crown preparation was performed on the left first molar teeth and digital impressions of prepared teeth were made. BI, BC, and BR crowns were designed. Occlusal images of designs including occlusal contacts were superimposed on the gypsum cast images and corresponding contacts were determined. Three designs were evaluated by the students. RESULTS. The results of the study revealed that there was significant difference among the number of contacts of gypsum cast and digital models (P<.05). The comparison of the percentage of virtual contacts of three crown designs which were identical to the contacts of original gypsum cast revealed that BI and BR designs showed significantly higher percentages of identical contacts compared with BC design (P<.05). Subjective assessment revealed that students generally found BI designs and BR designs natural regarding naturalness of fissure morphology and cusp shape and cusp tip position. For general occlusal morphology, student groups generally found BI design "too strong" or "perfect", BC design "too weak", and BR design "perfect". CONCLUSION. On a prepared tooth, three different biogeneric design modes of a CAD/CAM software reveals different crown designs regarding occlusal contacts and morphology.

• 구강회복응용과학지
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• 제31권2호
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• pp.143-149
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• 2015

전치부는 심미적인 관점에서 치열 및 연조직과의 조화가 매우 중요하다. 상악 전치부의 심미적인 치료는 술 전 정확한 진단과 치료계획이 필수적인데 술자는 특히 치관부 크기의 적절한 비율과 치은 형태의 대칭에 대해 충분히 고려해야 한다. 만약 치은의 형태가 비심적이고 부자연스러운 경우에는 치은 절제술, 골삭제를 동반한 치관 연장술, 교정적 정출술 등을 시행할 수 있다. 치관의 형태 및 위치가 부적절한 경우에는 술 전 진단 모형 및 왁스 업을 통해 교정 치료나 완전도재관, 라미네이트 베니어 등의 심미적 보철치료를 계획할 수 있다. 본 증례들에서는 치아의 위치 이상과 연,경조직의 부조화를 가진 전치부를 교정 치료 및 치은 성형과 심미적 보철 치료를 시행함으로써 만족할만한 결과를 얻었기에 이를 보고하고자 한다.

• 대한치과기공학회지
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• 제42권1호
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• pp.17-25
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• 2020

Purpose: The purpose of this study was to evaluate and compare the accuracy of definitive casts that are fabricated from digital intraoral impression and conventional impression technique. Methods: A master model(ANNA-4, Frasaco GmbH, Tettnang, Germany) with the prepared upper full arch tooth was used. Conventional impression and then stone model(n=10) were produced from this master model, and on the other hands, digital impressions were made with the CS-3600 intraoral scanner(n=10). Six linear measurements were recorded between landmarks, directly on each of the stone models on two occasions by a single examiner. Measurements were made with a digital caliper to the nearest 0.01mm from manual models and with the software(Delcam PowerSHAPE) from the virtual models. The t-student test for paired samples and intraclass correlation coefficient(ICC) were used for statistical analysis. Results: The measurement of two methods showed good reliability. The ICC of the two models were 0.88~0.91(stone model) and 0.94~0.99(digital model). The mean differences to master model for stone model and digital model were 0.10~0.14mm, and 0.14~0.20mm, respectively. Conclusion: The definitive casts obtained with digital intraoral technique model had significantly larger dimensions as compared to those of the stone model. However, the differences to the master model detected appear to provide enough accuracy and reliability for clinical application.

• 대한치과보철학회지
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• 제44권1호
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• pp.10-19
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• 2006

Statement of problem : The various kinds of properties of post and core may affect the stress distribution to the root of endodontically treated teeth Purpose: To evaluate the influence of various kinds of properties of post and core to the stress distribution to the root of endodontically treated teeth. Material and methods: Mandibular first premolar, prepared by general shape of post and core with gold crown, was used to two dimensional axisymmetric modeling for finite element analysis. Then property values of 8 different kinds of post and core was substituted for each. Finally, stress distribution shown areas around the root of post and core was analysed after applying 50N of vortical and oblique load. Results: 1. Stress value of oblique load was much higher than the maximum stress value of vertical load. 2. Under oblique load, very concentrated stress was located on post periapical area and variations in stress were very severe. Contrary to this, stress distribution was relatively uniform in vertical load. 3. Post materials with higher elastic modulus showed relatively more apically focused stress, and post materials with lower elastic modulus showed stress focused on cervical area on the axial wall of post. 4. Stress change according to the properties of core was shown only in the cervical area of post and below core as the higher elastic modulus, then increased in stress. 5. Post and core with medium value of elastic modulus showed relatively uniform stress distribution. Conclusions: Post materials with higher elastic modulus showed relatively more apically focused stress, and post materials with lower elastic modulus showed stress focused on cervical area on the axial wall of post. Stress change according to the properties of core was shown only in the cervical area of post and below core.