• Restorative Dentistry and Endodontics
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• 제28권6호
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• pp.485-490
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• 2003

Complete understanding of the exterior and interior structure of the tooth would be prerequisite to the successful clinical results, especially in the restorative and endodontic treatment. Although three-dimensional reconstruction method using x-ray microtomography could not be used in clinical cases, it may be the best way to reconstruct the morphologic characteristics of the tooth structure in detail without destructing the tooth itself. This study was done to three dimensionally reconstruct every teeth in the arch in order to increase the understanding about the endodontic treatment and to promote the effective restorative treatment by upgrading the knowledge of the tooth morphology. After placing tooth between the microfocus x-ray tube and the image intensifier to obtain two-dimensional images of each level. scanning was done under the condition of 80 keV, $100{\;}\mu\textrm{m}$, 16.8 magnification with the spot size of $8{\;}\mu\textrm{m}$. Cross-section pixel size of $16.28{\;}\mu\textrm{m}$ and 48.83 cross-section to cross-section distance were also used. From the results of this study, precise three dimensional reconstructed images of every teeth could be obtained. Furthermore, it was possible to see image that showed interested area only, for example. enamel portion only, pulp and dentin area without enamel structure, pulp only, combination image of enamel and pulp, etc. It was also possible to see transparent image without some part of tooth structure. This image might be used as a guide when restoring and preparing the full and partial crown by showing the positional and morphological relationship between the pulp and the outer tooth structure. Another profit may be related with the fact that it would promote the understanding of the interior structure by making observation of the auto-rotating image of AVI file from the various direction possible.

• Restorative Dentistry and Endodontics
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• 제17권1호
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• pp.95-103
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• 1992

The purpose of this study was to evaluate the effect of the dentin pretreatment on the marginal leakage of a glassionomer cement. 1n this study, 60 molars with sound and healthy crown portion were used. The dentin surface of these teeth were exposed and polished with 600 grit silicon carbide paper. Square - shaped cavities were prepared on the flattened dentin surfaces and these were divided into 4 groups according to the dentin pretreatment procedures. Group I : Dentin pretreatment with distilled water as a control group. Group II : Dentin pretreatment with 5% sodium hypochlorite solution. Group III : Dentin pretreatment with Ketac conditioner. Group IV : Dentin pretreatment with 40% polyacrylic acid. The degrees of dye penetration in the cavity walls were assessed using a stereoscope at ${\times}40$ magnification according to the maximum dye penetration. The results were analyzed by using Mann - Whitney U test. The results were as follows : 1. All groups showed varying depth of dye penetration. 2. Distilled water group showed the most severe marginal leakage when compared with the other groups(P<0.05). 3. 40% polyacrylic acid group showed the least amount of marginal leakage compared with the other groups (P<0.05). 4. There were significant differences between Goup I(distilled water) and Group IV (40% polyacrylic acid)(P<0.05), but there were no significant differences among Group I(distilled water), Group II(sodium hypochlorite), Group III(Ketac conditioner) (P>0.05).

• Restorative Dentistry and Endodontics
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• 제42권3호
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• pp.200-205
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• 2017

Objectives: The aim of this in vivo study was to assess the accuracy of 2 third-generation electronic apex locators (EALs), Propex II (Dentsply Maillefer) and Root ZX II (J. Morita), and radiographic technique for locating the major foramen (MF). Materials and Methods: Thirty-two premolars with single canals that required extraction were included. Following anesthesia, access, and initial canal preparation with size 10 and 15 K-flex files and SX and S1 rotary ProTaper files, the canals were irrigated with 2.5% sodium hypochlorite. The length of the root canal was verified 3 times for each tooth using the 2 apex locators and once using the radiographic technique. Teeth were extracted and the actual WL was determined using size 15 K-files under a ${\times}25$ magnification. The Biostat 4.0 program (AnalystSoft Inc.) was used for comparing the direct measurements with those obtained using radiographic technique and the apex locators. Pearson's correlation analysis and analysis of variance (ANOVA) were used for statistical analyses. Results: The measurements obtained using the visual method exhibited the strongest correlation with Root ZX II (r = 0.94), followed by Propex II (r = 0.90) and Ingle's technique (r = 0.81; p < 0.001). Descriptive statistics using ANOVA (Tukey's post hoc test) revealed significant differences between the radiographic measurements and both EALs measurements (p < 0.05). Conclusions: Both EALs presented similar accuracy that was higher than that of the radiographic measurements obtained with Ingle's technique. Our results suggest that the use of these EALs for MF location is more accurate than the use of radiographic measurements.

• Archives of Plastic Surgery
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• 제34권2호
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• pp.274-277
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• 2007

Purpose: Microsuturing is a difficult job for beginners of microsurgery. It is because they are not familiar with microscopic environment and, it needs much time for them to get used to microanastomosis. Before the real microsurgery, sometimes a surgeon wants rehearsal. But, microsurgical exercise has been performed with surgical glove, silastic drain or rat femoral artery. Rat femoral artery is a very good training material. But, it needs animal laboratory, anesthesia and its keeping facilities. And the surgeon should appoint the time to exercise with the laboratory. Methods: We used chicken wing brachial artery for education material of microsuturing. The artery is 5 cm long and the diameter is about 1 mm. Monofilament 10-0 was used for suture material. Results: Six persons of Seoul National University medical school students and one resident attended in this program. Each of them performed arterial anastomosis ten times. They were satisfied with chicken wing brachial artery for anastomosis training under the magnification environment. Conclusion: We think that chicken wing brachial artery is a very cheap and an effective training material for the beginners of microsurgery.

• Archives of Plastic Surgery
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• 제38권5호
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• pp.642-648
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• 2011

Purpose: The recent advances in microsurgical techniques and their refinement over the past decade have greatly expanded the indications for digital replantations and have enabled us to salvage severed fingers more often. Many studies have reported greater than 80% viability rates in replantation surgery with functional results. However, replantation of multi-level amputations still remain a challenging problem and the decision of whether or not to replant an amputated part is difficult even for an experienced reconstructive surgeon because the ultimate functional result is unpredictable. Methods: Between January of 2002 and May of 2008, we treated 10 multi-level amputated digits of 7 patients. After brachial plexus block, meticulous replantation procedure was performed under microscopic magnification. Postoperatively, hand elevation, heat lamp, drug therapy and hyperbaric oxygen therapy were applied with careful observation of digital circulation. Early rehabilitation protocol was performed for functional improvement. Results: Among the 19 amputated segments of 10 digits, 16 segments survived completely without any complications. Overall survival rate was 84%. Complete necrosis of one finger tip segment and partial necrosis of two distal amputated segments developed and subsequent surgical interventions such as groin flap, local advancement flap and skin graft were performed. The overall result was functionally and aesthetically satisfactory. Conclusion: We experienced successful replantations of multi-level amputated digits. When we encounter a multi-level amputation, the key question is whether or not it is a contraindication to replantation. Despite the demand for skillful microsurgical technique and longer operative time, the authors' results prove it is worth attempting replantations in multi-level amputation because of the superiority in aesthetic and functional results.

• Radiation Oncology Journal
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• 제4권2호
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• pp.179-181
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• 1986

최근 방사선치료영역에 있어 CT의 역할은 매우 중요시되고 있다. 종래의 병기결정 등 진단적가치 이외에도 방사선치료분야에 있어서는 환자신체의 윤곽 종양침습 범위, 인접 정상구조물의 위치, 조직불균질성의 정도 등을 정확하게 파악할 수 있고 입체적영상의 재구성도 가능하여 주위 정상조직의 손상 없이 충분한 종양치료선량을 조사하는데 있어 거의 필수이라고 까지 할 수 있다. 이와 같은 진단용 CT상은 모두 실물크기를 일정 비율로 축소시킨 영상으로 기록 및 보관되고 있는 바 방사선치료계획시 이 축소된 CT상을 치료계획용 콤퓨터에 입력할 경우 같은 CT영상일지라도 치료의사에 따라서 또 입력할 때마다 조금씩 차이가 생길 수 있음으로 이와 같은 오차를 줄이기 위하여는 실물크기의 영상이 필요하게 된다. 저자들은 축소된 CT영상을 실물크기로 확대하기 위하여 overhead projector(3M사제)와 평면거울을 부착시킨 정맥주사용 Pole을 이용하여 값싸고 간단한 장치를 고안하였으며, 이를 사용하여 쉽게 실물크기영상을 치료계획용콤퓨터 (Thenac 2000, NEC제)의 입력판위에 얻을 수 있었기에 보고하는 바이다.

• 한국방사선학회논문지
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• 제4권1호
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• pp.19-24
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• 2010

콘빔형 소동물용 CT 장치는 바이오-의료분야의 기초 실험에 활발히 응용되고 있다. $10{\mu}m$의 직경을 가진 텅스텐 와이어(wire)와 물 팬텀을 이용하여 비교적 간단한 방법으로 소동물용 CT 장치를 평가할 수 있는 방법을 제시하였다. X선 튜브가 안정적으로 장시간 운전 가능한 조건에서 $1^{\circ}$ 간격으로 360개의 투영영상을 획득하고, 영상재구성을 통하여 슬라이스 영상 및 3차원 영상을 얻었다. 콘빔형 소동물용 CT 장치는 배율 1.07배 위치에서 13.78lp/mm(공간해상도 $36.2{\mu}m$)를 나타내었고, 80kV의 관전압에서 CNR 10.33 및 S/N 5.87을 보였다.

• 한국레이저가공학회지
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• 제6권3호
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• pp.19-28
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• 2003

The manufacturing process for the microfluidic device can include sequential steps such as master fabrication, electroforming, and injection molding. The laser ablation, using masks, has been applied to the fabrication of channels in microfluidic devices. In this research, an excimer laser was used to engrave microscopic channels on the surface of PET (polyethylene terephthalate), which shows a high absorption ratio for an excimer laser beam with a wavelength of 248 m. When 50-${\mu}{\textrm}{m}$-wide rectangular microscopic channels are ablated with a 500 ${\times}$ 500 ${\mu}{\textrm}{m}$ square mask at a magnification ratio of 1/10, ditch-shaped defects were found in both corners. The measurement of laser beam intensity showed that a coherent image in the PET target caused such defects. Analysis based on the Fourier diffraction theory enabled the prediction of the coherent shape at the image surface as well as the diffraction beam shape between the mask and the image surface. It also showed that the diameter of the aperture had a dominant effect. The application of aperture with a diameter of less than 3 mm helped to eliminate such defects in the ablated rectangular microscopic channels on PET without such ditch-shaped defects.

• 패션비즈니스
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• 제6권4호
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• pp.32-45
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• 2002

The purpose of this study is, to renew understanding the aesthetic value of a ruff collar and to expand the border of creation in designing as the source of inspiration being applied to an retro style by inquiring various ruff collars re-illuminated in the present-day fashion trend. The ruff collar investigated through the above historical contemplation became the source of inspirations in the current retro trend and was variously modified in modern fashion. In the 1980s, we can find a dignified and feminine image in graceful and exquisite suits or dresses. Especially, the spanish round ruff of the 2st period appeared on works by a lot of designers. From the application by designers like John Galliano in the latter half of the 80s, we can be well aware that the meaning of decoration was newly altered. In the 1990s, the ruff collar was shown in various fashion style, but it was what was reborn as a factor of modern fashion through a liberal compromise and harmony. Various style was shown from exaggeratedly swelling one to smaller one, which were more diversely applied than that of the 80s. A Medici collar and a Queen Elizabeth collar were also displayed being fitted to a modern sense by Vivienne Westwood and Louis F raud. A ruff in the 2000s was settled as a factor of modern fashion, exposing on works of designers more often than in the 1980s and 90s. The spanish round ruff appeared on garments, while a Medici collar and a Queen Elizabeth collar went out of sight. A new form of the ruff was regenerated by extreme magnification and simplification, and several designers like Issey Miyake and Alexander Mcqueen brought forward a new way in materials and technical skills. According to this research, a ruff collar developed as a fashion factor which characterizes a certain period of time, reflecting the aesthetical sense of Renaissance and turning into various and distinct forms. Afterwards, it exerted influence on modern fashion. This is offering the source of inspiration to contemporary designers.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권9호
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• pp.610-615
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• 2015

카메라 기반의 원격 시선 추적 방식은 기기의 특성상 사용자의 움직임 등의 요인에 의해 시선 추적의 정확성 측면에서 많은 영향을 받는다. 하지만 턱받침을 사용하여 사용자의 움직임을 제약하는 실험 환경은 시선 추적의 정확성을 높이는 대신 비침습적인 시선 추적 방식의 이점을 사라지게 한다. 이 논문에서는 비침습적인 추적 방식에서 나타날 수 있는 정확도의 저하를 극복하기 위하여 높은 정확도가 요구되는 관심 영역을 화면상에서 확대함으로써 해상력을 높이는 방안을 제시한다. 관심 영역의 확대는 두 종류의 조건(상시, 조건부)에 의해 이루어 졌으며, 이를 기존 시선 추적 방식과 비교했다. 또한 이렇게 비교한 결과를 바탕으로 적응형 확대 기법의 장점과 한계를 정리했다.