• 구강회복응용과학지
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• 제20권1호
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• pp.9-17
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• 2004

In this study, the biomechanical characteristics of Kimplant were compared with that of Branemark implant by using three dimensional finite element analysis. Two finite element models were fabricated by inserting each implant into the bone model. The bone model was designed to have 18mm height, 13mm width and 15mm length. The size of each implant was planned to have 4mm width and 10mm length. A 200N force was applied on the center of abutment top in three directions - vertical, horizontal and oblique. After analyzing the stresses of fixture and surrounding bone, following results were obtained. 1. There was similar stress distribution between the two models. 2. The magnitude of maximum principal stress on the implant was similar between the two models but the location of maximum principal stress on the implant was different. 3. The magnitude and location of maximum principal stress on the surrounding bone was similar between the two models.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집
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• pp.10-11
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• 2008

We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 levels by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage. And then, each experiment was performed to irradiation group and non-irradiation group for bone marrow cells. MIT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of bone marrow cells was verified in irradiation group as compared to non-irradiation group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권3호
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• pp.211-217
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• 2020

In patients with insufficient bone height and width, the successful placement of dental implants is difficult with regards to maintaining an ideal pathway and avoiding important anatomical structures. Vertical and/or horizontal ridge augmentation may be necessary using various bone substitute materials and bone graft procedures. However, effective one-wall reconstruction has been challenging due to its poor blood supply and insufficient graft stability. In this paper, the authors summarize current evidence-based literature based on the author's clinical experience. Regarding bone substitutes, it is advantageous for clinicians to select the types of bone substitutes including autogenous bone. The most important consideration is to minimize complications through principle-based ridge augmentation surgery. Ridge augmentation should be decided with complete consent of the patients due to the possible disadvantages of surgery, complications, and unpredictable prognosis.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.461-471
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• 2006

In order to achieve a satisfactory esthetic result of periodontal surgery or implant in maxillary anterior area, periodontists must be aware of normal alveolar bone anatomy. The purpose of this study was to evaluate the relationship of alveolar bone morphology to tooth shape and form. 78(mean age : 25 yrs) periodontally healthy volunteers participated in this study. Two maxillary central incisor and one lateral incisor were selected to study. With minimal local anesthesia, gutta-percha cone inserted to labial gingival sulcus of selected teeth just after bone sounding with periodontal probe. Metal ball (4mm diameter) attached to palatal fossa of central incisor. Then, periapical radiograph was taken according to long cone paralleling technique. After film scan, labial alveolar bone profile reproduced along interproximal bone and apical ends of gutta-percha cones on computer screen. By utilizing computer program, the distance from height of interproximal bone to the labial bone crest in central incisor-central incisor and central incisor-lateral incisor area was measured and converted to real distance by using vertical length of metal ball on film. After measuring crown length & width of central incisor, the 10 individuals ranked lowest GW/L ratio (crown width/length ratio) and the 10 ranked highest were selected as having a long-narrow(group N), or a short-wide(group W) form of the central incisors. Means of the distance from height of interproximal bone to the labial bone crest of group N, W were calculated and compared by means of independent t-test. The results were as follows: 1. Mean distance from the height of the interproximal bone to the labial bone crest was $3.5{\pm}0.7mm$ between two central incisor, and $2.8{\pm}0.6mm$ between central and lateral incisor. 2. Mean GW/L ratio of group N was 0.57, and group W was 0.8. Mean distance from the height of the interproximal bone to the labial bone crest of group N was higher than group W in both measured area(measurements of group N, W were $3.9{\pm0.2mm$ and $3.5{\pm}0.2mm$ between two central incisor, $3.0{\pm}0.2mm$ and $2.8{\pm}0.2mm$ between central and lateral incisor), but there were no statistically significant differences when the groups were compared. Within the limits of the present study, there was a tendency that subjects with long-narrow teeth have more scalloped alveolar bone profile than subjects with short-wide teeth in upper anterior area, but no statistically significant differences were found.

• Archives of Plastic Surgery
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• 제36권4호
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• pp.445-449
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• 2009

Purpose: A successful surgical treatment for a wide alveolar cleft with bone graft is difficult to achieve due to several factors such as the limitation of gingivoperiosteal flap, the presence of large scar tissues, and the poor blood circulation. To overcome these problems, alveolar distraction osteogenesis using Liou alveolar distraction device was applied. We analyzed the consequences of this surgical treatment. Method: Between 2006 January and 2007 August, we have conducted analysis on the methods and consequences of Liou alveolar distraction osteogenesis for 6 patients. The age of patients was 12 years and 6 months in average. The follow up period was 19 months in average. The Reverse L osteotomy followed by the placement of the Liou alveolar distraction device was performed. After serial distraction, the distractor was removed after 5 months of the process of osteogenesis, and the result was analyzed using the computed tomography and the x-ray films of the alveolar bone and the teeth. Results: The alveolar cleft with 12.5 mm in average width was filled with 8.5 mm of newly formed bone tissue in average width after 5 months of osteogenesis. Among the 6 cases, 5 required the additional bone graft and 1 case only required the gingivoperioplasty. The newly formed bone tissues did not show any signs of bone resorption. However, a considerable degree of teeth displacement was shown. Conclusion: For the alveolar cleft too wide to be reconstructed by a general bone graft, it is strongly recommended to perform the reverse L osteotomy of the cleft side with Liou alveolar distraction device to initiate the alveolar osteogenesis. However, the migrated teeth showed some degree of relapse, thus, the orthodontic treatment is essential following the distraction osteogenesis treatment.

• Imaging Science in Dentistry
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• 제50권3호
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• pp.217-226
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• 2020

Purpose: The purpose of this study was to analyze the quantity and quality of the mandibular anterior alveolar bone in terms of alveolar width, density, and total alveolar height (TAH) based on dental status, gender, and age. Additionally, this study aimed to quantitatively evaluate the available alveolar height for graft harvesting (AHGH) and examine its variability based on the aforementioned factors. Materials and Methods: This retrospective cone-beam computed tomographic study included a total of 100 subjects. On the basis of gender, dental status, and age, the scans were divided into 3 primary groups and 8 subgroups. The mandibular alveolar width and density were measured 5 mm mesial to the mental foramen bilaterally and at the midline. The TAH was measured at the midline, and the AHGH was measured as the midline distance between 5 mm apical to the root of the canines and 5 mm superior to the lower border. Results: The mandibular alveolar width was statistically similar between dentulous and edentulous patients (P>0.05). A significantly greater density was observed at the midline in edentulous patients (P<0.05). The TAH was significantly greater in edentulous male patients than in edentulous female patients (P<0.05). Dentulous and male patients had significantly greater AHGH than edentulous and female patients, respectively (P<0.05). Conclusion: Based on the data evaluated in this study, it can be concluded that the mandibular symphyseal area has adequate bone quality and quantity for bone graft harvesting for dental implant therapy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.223-225
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• 2007

Online models predicting roll force and forward slip of roughing mill was developed using nondimensional parameters. Using the effective inlet thickness, roll force model take into account the effect of inlet dog-bone shape of slab which take places after width reduction through edger rolling in roughing mill. The prediction accuracy of the proposed model is examined through comparison with measurements.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권5호
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• pp.390-398
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• 2005

Purpose: The aim of this study was to evaluate the skeletal and dentoalveolar dimensional changes following surgically-assisted rapid maxillary expansion (SARME). Patients & methods: Thirteen adults who had been treated by SARME for transverse maxillary deficiency from May 2000 to December 2003 were evaluated. The SARME procedure was the subtotal Le Fort I osteotomy combined with pterygomaxillary separation and anterior midpalatal osteotomy. Dental study casts and posteroanterior cephalometric radiographs were taken before operation, after removal of expansion device, and follow up period. Nasal cavity width, skeletal and dentoalveolar parameters were measured pre- and post-operatively. Results: 1. Mean nasal cavity width was increased 12%$(0{\sim}21%)$ of total expansion after retention. 2. Mean maxillary interdental width was increased 70%$(47{\sim}99%)$, 95%$(84{\sim}115%)$, and 77%$(57{\sim}94%)$ of total expansion in the canine, the first premolar, and the first molar region, respectively after retention. 3. Mean maxillary alveolar bone width was increased 66%$(42{\sim}84%)$, 74%$(42{\sim}94%)$, and 57%$(31{\sim}78%)$ of total expansion in the canine, the first premolar, and the first molar region, respectively after retention. 4. Mean palatal vault depth was decreased 1.3 mm ($0.5{\sim}2.0$ mm) after retention. 5. Mean interdental and alveolar bone width of the mandibular canine and intermolar width of mandible were slight increased as maxilla was expanded after retention. 6. There were statistical differences between preoperative and postoperative values of nasal cavity, all maxillary interdental and interalveolar widths, palatal vault depth, mandibular interdental and interalveolar width of canine(paired t-test, p<0.05). 7. The maxillary interdental and alveolar bone width were decreased approximately 25% of total expansion by relapse at follow up period. Conclusion: In conclusion, most amounts of maxillary interdental expansions were acquired with the expansion of the maxilla by SARME. For preventing the relapse, approximately 25% of the overexpansion was needed.

• 소성∙가공
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• 제12권7호
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• pp.668-674
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• 2003

Rigid-plastic finite element analyses on the deformation of slabs at various width reductions have been performed. By using commercial finite element code, dog-bone profile, crop profile and the longitudinal width profile after edging and Horizontal rolling have been analysed. The deformation behavior of slab for the heavy edger mill has also been compared with that for the sizing press. From the deformation analyses, it was found that the sizing press-horizontal rolling method is more efficient in width reduction than that of heavy edger mill-horizontal rolling. The results of finite element analyses fer the deformation of slab were well confirmed by the actual operational data. It was found that the amount of width variation after sizing and rolling is about 5∼10mm.

• 암석학회지
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• 제13권4호
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• pp.191-200
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• 2004

경북 군위군 학성리 화북댐 건설예정지 북측 1km지점을 북서-남동방향으로 통과하는 우보단층은 20km 내외의 연장을 가지는 대단층이다. 이 지역에서 우보단층은 소규모의 단층들로 분절되며 인접 지역에 비해 단층의 영향이 적고 낮은 구릉형 지형을 형성하며 화북댐 우안의 분수령을 통과한다. 저수유역내에 2매의 단층이 통과하며 파쇄대의 영향범위는 2m 내외로 관찰된다. 지화학분석을 통해 파쇄대 영향범위를 평가하기 위해 주단층면을 중심으로 남북방향으로 각각 0.5m, 1m, 2m, 4m, 8m, 16m, 32m구간에서 시료를 채취하여 주성분원소와 광물함량비를 분석하였다. 파쇄대에 근접할수록 Fe$_2$O$_3$, MgO, $K_2$O, 석영, 백운모, 녹니석은 증가하는 경향을 보이며, $Na_2$O, CaO, 사장석, 흑운모는 감소하는 경향을 보인다. 화학조성과 광물함량비를 기초로 학성리일대를 통과하는 우보단층의 파쇄대 영향범위는 중심지역이 총 2m의 폭을 보이며 2차 영향대는 총 8m의 폭을 이룬다. 우보단층의 최대 영향범위는 총 16m의 폭을 가지는 것으로 추정하였다.