IPS Empress 도재관의 파절강도 : 상악 견치에서 절단연 삭제량과 축면 경사도에 따른 영향

신동국,강한중,박용석,박광수,동진근,Shin Dong-Kuk,Kang Han-Joong,Park Yong-Suck,Park Kwang-Soo,Dong Jin-Keun 대한치과보철학회 2005 대한치과보철학회지 Vol.43 No.1

Purpose. The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the incisal reduction (2.0mm, 2.5mm, 3.0mm) and axial inclination ($4^{\circ}$, $8^{\circ}$, $12^{\circ}$) of the upper canine. Material and methods. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and each crown was cemented on each metal die with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and the universal testing machine was used to measure the fracture strength. Results. 1. The fracture strength of the ceramic crown with 3.0mm depth and $12^{\circ}$ inclination was the highest (839N) Crowns of 2.0mm depth and $12^{\circ}$ inclination had the lowest strength (559N). 2. There was no significant difference in the fracture strength by axial inclination in the same incisal reduction group. 3. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the margin irrespective of incisal reduction.

국부적 영역에서의 특징 공간 속성을 이용한 다중 인식기 선택

신동국(Dong-Kuk Shin),송혜정(Hye-Jeong Song),김백섭(BaekSop Kim) 한국정보과학회 2004 정보과학회논문지 : 소프트웨어 및 응용 Vol.31 No.12

본 논문은 시험 표본 주위의 영역에 대한 속성을 이용한 다중 인식기 선택 방법을 제안한다. 기존의 DCS-LA 동적 인식기 선택 방법은 시험 표본 주위의 학습표본들을 사용해서 각 인식기의 국부적정확성을 계산하여 인식기를 동적으로 선택하기 때문에 인식 시간이 오래 걸린다. 본 논문에서는 특징공간에서 국부적인 속성을 계산해서 그 속성값에 적합한 인식기를 미리 선정해서 저장해 놓은 후 시험 표본이 들어오면 그 주변의 속성값에 따라 저장된 인식기에서 선택을 하기 때문에 인식시간을 줄일 수 있다. 국부적인 속성으로는 표본 주위의 작은 영역에 대한 엔트로피와 밀도를 계산하여 사용하였으며 이들을 특징공간속성(Feature Space Attribute)라고 하였다. 이들 두 속성으로 이루어지는 속성 공간을 규칙적인 사각형 셀로 나누어, 학습과정에서 각각의 학습표본에 대해 계산된 속성값이 어떤 셀에 속하는지를 구한다. 또한 각 셀에 속하는 학습표본들에 대해 각 인식기의 국부적 정확도를 구하여 셀에 저장한다. 시험 과정에서 시험표본에 대해 속성값 계산을 통해 그 표본이 속하는 셀을 구한 후 그 셀에서 국부적 정확도가 가장 높은 인식기로 인식한다. Elena 데이타베이스를 사용해서 기존의 방법과 제안된 방법을 비교하였다. 제안된 방법은 기존의 DCS-LA와 거의 같은 인식률을 나타내지만 인식속도는 약 4배 가까이 빨라짐을 실험을 통해 확인할 수 있었다. This paper presents a method for classifier selection that uses distribution information of the training samples in a small region surrounding a sample. The conventional DCS-LA(Dynamic Classifier Selection - Local Accuracy) selects a classifier dynamically by comparing the local accuracy of each classifier at the test time, which inevitably requires long classification time. On the other hand, in the proposed approach, the best classifier in a local region is stored in the FSA(Feature Space Attribute) table during the training time, and the test is done by just referring to the table. Therefore, this approach enables fast classification because classification is not needed during test. Two feature space attributes are used : entropy and density of k training samples around each sample. Each sample in the feature space is mapped into a point in the attribute space made by two attributes. The attribute space is divided into regular rectangular cells in which the local accuracy of each classifier is appended. The cells with associated local accuracy comprise the FSA table. During test, when a test sample is applied, the cell to which the test sample belongs is determined first by calculating the two attributes, and then, the most accurate classifier is chosen from the FSA table. To show the effectiveness of the proposed algorithm, it is compared with the conventional DCS-LA using the Elena database. The experiments show that the accuracy of the proposed algorithm is almost same as DCS-LA, but the classification time is about four times faster than that.

상악 제1소구치의 교두각에 따른 전부도재관의 응력분포에 관한 삼차원유한요소법적 연구

김원규,신동국,송기범,동진근,Kim Won-Kyu,Shin Dong-Kuk,Song Kie-Bum,Dong Jin-Keun 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.1

Statement of problem : Clinically, maxillary first premolar has a high risk of fracture. This is thought to be caused by the susceptible figure which the maxillary first premolar has In other words, sharp cusp angles of the premolar is thought to influence this situation. Purpose : This study was to know stress distribution of all-ceramic crown according to the cusp angle. Material and Method : It was manufactured a three dimensional finite element model simplified maxillary first premolar, and then analyzed stress distribution when cusp angle was each $80^{\circ}$, $90^{\circ}$, $100^{\circ}$, $110^{\circ}$ and $120^{\circ}$. Results and conclusion : 1. The von Misses stress showed that stress decreases as cusp angle increases in the central groove of the occlusal surface. 2. It showed that maximum principal stress was centered at the region of the central groove of the occlusal surface and a region which the force was inflicted. And also it appeared high on the lingual and buccal side of finish line. 3. The X axis of normal stress was focused in the central groove of the occlusal surface. The Y axis normal stress appeared high in the central groove of the occlusal surface, buccal and lingual side. 4. The Stress near the finish line showed a low value compared with stress in the region of the central groove of the occlusal surface. 5. It shows that the most dangerous angle for tooth fracture was on $80^{\circ}$ of the cusp angle and low on $120^{\circ}$ of its.

초음파 영상의 빠른 모자이크를 위한 국소 움직임 추출

신성철(Seong Chul Shin),신동국(Dong Kuk Shin),정우철(Woo Cheol Jeong),김종대(Jong-Dae Kim),김백섭(Baek-Sop Kim),이기종(Ki-Jong Lee),배무호(Moo-Ho Bae) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.2004 No.1

IPS Empress 도재관의 파절강도

정영찬(Young-Chan Jung),신동국(Dong-Kuk Shin),박은주(Eun-Ju Park),김민정(Min-Jeong Kim),동진근(Jin-Keun Dong) 대한턱관절교합학회 2004 구강회복응용과학지 Vol.20 No.1

유지형태에 따른 치과 인상용 트레이의 유지력에 관한 연구

최민호(Min-Ho Choi),신동국(Dong-kuk, Shin),김민정(Min-Jeong Kim),오상천(Sang-Chun Oh),동진근(Jin-Keun Dong) 대한턱관절교합학회 2004 구강회복응용과학지 Vol.20 No.1

시멘트 두께에 따른 IPS Empress 도재의 전단결합강도에 관한 연구

신동국,송병권,동진근 원광대학교 치의학연구소 1999 圓光齒醫學 Vol.9 No.1

The purpose of this study was to compare the shear bond strength of IPS Empress ceramic according to resin cement thickness. To evaluate the shear bond strength between IPS Empress and dentin, the 48 IPS Empress ceramic specimens(diameter 5㎜, length 6㎜) were cemented with Variolink Ⅱ cement (Vivadent, Liechtenstein) to human molars which had a uniform area of exposed dentin. Resin cement thicknesses were 10μm, 30μm, 50μm, and 100μm, which were made by a modified micrometer. The specimens were thermocycled 1000 times at temperature of 5℃ and 55℃. The shear bond strength of the cemented specimens was measured with a universal testing machine(Zwick 1456 41,Zwick Co., Germany) with a crosshead speed of 0.5㎜/min. The obtained results were as follows: 1. The shear bond strength of the 10μm thickness group was the highest of all. The mean shear bond strength was 12.19㎫ in the 10 pm thickness group, 9.30㎫ in the 30μm thickness group, 8.79㎫ in the 50μm thickness group, and 7.40㎫ in the 100μm thickness group. The shear bond strength of the 10μm thickness group was statistically different from the 50μm thickness group and the 100μm thickness group. (p<0.05) 2. The fracture pattern of IPS Empress ceramics occurred between the teeth and the resin cements in all specimens.

상악 제1소구치의 교두각에 따른 전부도재관의 응력분포에 관한 연구

김원규,신동국,송기범,동진근 원광대학교 치의학연구소 2003 圓光齒醫學 Vol.12 No.3

The purpose of this study was to know stress distribution of ceramic crown according to the cusp angle. For the study, it was manufactured a three dimensional finite element model simplified maxillary first premolar, and then analyzed stress distribution when cusp angle was each 80°, 90°, l00°, 110° and 120°. The results obtained were as follows; 1. The von Mises stress showed that stress decreases as cusp angle increases in the central groove of the occlusal surface. 2. It showed that maximum principal stress was centered at the region of the central groove of the occlusal surface and a region which the force was inflicted. And also it appeared high on the lingual and buccal side of finish line. 3. The X axis of normal stress was focused in the central groove of the occlusal surface. The Y axis of normal stress appeared high in the central groove of the occlusal surface, b u d and lingual side. 4. The stress near the finish line showed a low value compared with stress in the region of the central groove of the occlusal surface. 5. It showed that the most dangerous angle for tooth fracture was on 80° of the cusp angle and low on 120° of its.

숯 처리에 의한 녹차 추출액 중 질산태질소 제거 효과

김진우,고영옥,신동국,이 협,전현식,이종옥 진주산업대학교 산업과학기술연구소 2005 산업과학기술연구소보 Vol.- No.12

This experiment was carried out to measure the elimination effect of nitrate nitrogen from green tea extracts through the column system filled with charcoal activated and bamboo charcoal powder compare to that of an nitrate nitrogen standard solution prepared with KNO3 chemicals. The change patterns of pH, and the amount of removed nitrate nitrogen from green tea and nitrate nitrogen standard solution were analyzed according to time course and the amount of charcoal treatments. The results were summarized as follow: 1. pH The pH of Green tea extractions treated with charcoal was high up to 8.17(after 30min treated with 0.4% charcoal) and 8.36(after 60min with 0.4% charcoal) which pH of non-treated green tea (control) was 5.8 The results indicated that the pH values were variable to the treated amount of charcoal and the teated time course. 2. Nitrate nitrogen From the nitrate nitrogen standard solution, the least rate 69.1% and the highest rate 74.5% of nitrate nitrogen were observed to be absorbed through the column treatment (60 min), which with green tea extract solution 21.3% (the least) and 43.8% (the highest) were detected to be absorbed through column treatment (after 60min with 0.4% charcoal). In the case of bamboo treatments with nitrate nitrogen solution samples were showed the least rate 62.8% (30min with 0.1% bamboo) and the highest rate 68.9% (60min with 0.4% bamboo), and with green tea extract solution were observed the least 13.6 (30min with 0.1% bamboo) the highest rate 29.4% (60min with 0.4% bamboo). In general, the elimination activity of nitrate nitrogen was higher by the charcoal activated powder treatment than bamboo charcoal.