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황윤찬,강인철,황인남,오원만 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.5
This study was performed to evaluate the sealing ability of various retrograde filing materials by using bacterial penetration and dye penetration test. One hundred and forty extracted human teeth with single, straight canals and mature apices were collected and used for this study. All canals were instrumented using an engine driven Ni-Ti file (ProFile). After removing 3mm from the apex of tooth, a standardized 3mm root end cavity was prepared using an ultrasonic instrument. The 70 teeth were randomly divided into 7 groups : 6 groups for retrograde filling using Super-EBA, ZOE, Chelon-Silver, IRM, ZPC and amalgam. The 7th group was used as a negative control. Nail varnish was applied to all external root surfaces to the level of the resected root ends to prevent lateral microleakages. The specimens were then sterilized in an ethylene oxide sterilizer for 24 hours. 2 mm of the rejected root was immersed in a culture chamber containing a Tripticase Soy Broth with a phenol red indicator. The coronal access of each specimen was inoculated every 72 hours with suspension of Proteus vulgaris. The culture media were observed every 24hours for color change indicating bacterial contamination. The specimens were observed for 4weeks. The remaining 70 teeth were submitted to a dye penetration test. The canals of all teeth were first sealed with AH26 and obturated using an Obtura II system. Root resection, root end preparation and retrograde filling was performed as above. All specimens were suspended in 2% methylene blue dye for 72 hours before being longitudinally split. The degree of dye penetration was then measured using a stereomicroscope at 10 magnification and evaluated. The results were as follows : 1.In the bacterial penetration, the degree of leakage was the lowest in the Super-EBA, followed by, in ascending order, ZOE, Chelon-Silver IRM and ZPC. The amalgam showed highest bacterial leakage of all(p<0.01) . 2.In the dye penetration, the degree of microleakage was the lowest in the Chelon-Silver and Super-EBA, followed by, in ascending order, IRM, ZPC. The ZOE and amalgam showed the highest microleakage of all(p<0.05) . These results suggested that the eugenol based cement, Super-EBA, have excellent sealing ability as a retrograde filling material.
레이저 직접 패터닝에 의한 폴리이미드의 표면 특성 제어
황윤찬,손정민,박재희,남기호 한국염색가공학회 2023 韓國染色加工學會誌 Vol.35 No.2
In this study, a comprehensive investigation was conducted on the morphological and property changes of laser-induced nanocarbon (LINC) as a function of laser process parameters. LINC was formed on the surfaces of polyimide films with different backbone structures under various process conditions, including laser power, scan speed, and resolution. Three different forms of LINC electrodes (i.e., continuous 3D porous graphene, wooly nanocarbon fibers, line cut) were formed depending on the laser power and scan speed. Furthermore, heteroatom doping induced from the chemical structure of the polyimide during laser patterning was found to be effective in modifying the electrical properties of LINC electrodes. The LINC surfaces exhibited different microstructures depending on the laser beam resolution under constant laser power and scan speed, allowing for controllable surface wettability. The correlation between the chemical structure of the polymer substrate, laser process parameters, and carbonized surface properties in this study is expected to be utilized as fundamental understanding for the manufacturing of next-generation carbon-based electronic devices.
황윤찬 대한치과의사협회 2021 대한치과의사협회지 Vol.59 No.6
Root resorption is very rare disease in the dental field. However, when dentist faced root resorption in the clinic without knowledge, it is very difficult situation to solve. Root resorption can be classified into external root resorption and internal root resorption according to developing place of resorption. Also, root resorption is classified into surface resorption, inflammatory resorption, replacement resorption according to developing reason of resorption. In this article, we can understand the cause and reason of root resorption development and can know how to prevent and treat the root resorption
[장려상] 유전 알고리즘을 이용한 스도쿠 퍼즐 생성 및 풀이 방법
황윤찬 (사)한국CDE학회 2015 한국CAD/CAM학회학회지 Vol.21 No.2
A Sudoku puzzle is a kind of magic square puzzle which requires a non-repeated series of numbers from 1 to 9 in each 9 rows and 9 columns. Furthermore it contains total of 9 small three-bythree matrices, which need non-repeated numbers from 1 to 9 as well. Therefore the total number of possible cases of Sudoku puzzle is finite, even though that of creating nine-by-nine square is exponentially great. Accordingly a certain set of way is need not only for solving the puzzle, but also creating a new one. In this study, the method for creating a Sudoku puzzle applying genetic algorithm is suggested and will be demonstrated. Also, it will be shown that a Sudoku puzzle can be solved by genetic algorithm.
ProFile? , ProTaper™ 및 K3™ Ni-Ti파일의 과기구 조작이 치근단공 변위에 미치는 영향
양현,양인석,황윤찬,황인남,윤숙자,김원재,오원만 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.2
ProFile, ProTaperTM 및K3TM Ni-Ti 파일의 과기구 조작이치근단공 변위에 미치는 영향양 현1ㆍ양인석1ㆍ황윤찬1ㆍ황인남1ㆍ윤숙자2ㆍ김원재3ㆍ오원만1*1전남대학교 치의학전문대학원 보존학교실, 2구강악안면방사선학교실, 3