• 구강회복응용과학지
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• 제31권1호
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• pp.20-25
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• 2015

목적: 이 실험의 목적은 장석계 도재에 항균성을 부여하기 위해 은을 다양한 농도로 첨가하였을 때, 은 첨가가 장석계 도재의 색조에 영향을 미치는지 알아보기 위함이다. 연구 재료 및 방법: 대조군은 은을 포함하지 않은 일반 장석계 도재를 이용하고, 은이 5%, 10%, 20%, 30%의 농도로 첨가된 장석계 도재를 4개의 실험군으로 하여 총 5개의 그룹을 이용하였고, 각 그룹당 각 5개씩 디스크 형태로 시편을 제작하였다. 각 시편은 색차계를 이용하여 L, a, b값을 2번씩 측정하였다. 각 값은 SPSS를 이용하여 일원분산 통계 분석을 시행하였다. 결과: 은의 함량이 높아짐에 따라 각 그룹간 L값은 거의 비슷하였고, a값은 점차 증가하고, b값은 점점 감소하는 양상을 보여주었다. 은의 함량이 높아짐에 따라 ${\Delta}E$ 값은 유의하게 증가하였다. 5% 은 이온이 함유된 도재와 10%의 은 이온이 함유된 도재는 ${\Delta}E$값이 3.7 이하였다. 결론: 장석계 도재에 은을 첨가하는 것은 도재의 색조에 영향을 준다. 하지만 10% 이하의 이온을 첨가한 장석계 도재는 임상적으로 받아들여질만 하다.

• 대한치과보철학회지
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• 제38권5호
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• pp.606-617
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• 2000

The purpose of this study was to measure the marginal fidelities and the fracture strength of IPS Empress $2^{(R)}\;and\;In-Ceram^{(R)}$ ceramic crowns. After constructed of 12 experimental dies for each group, ceramic crowns were fabricated on the metal master dies prepared on the maxillary right premolar Marginal gaps were measured on the specimen between the margin of each crown and finish-ing line of the metal master die by using stereo-microscope($SZ-ST^{(R)}$ Olympus, Japan) and all specimens were cemented on the metal master die with Bistite $II^{(R)}$ (Tokuyama soda Co, LTD., Japan) resin cement. Finally marginal gaps were measured again. To measure of the fracture strength, buccal incline on the functional cusp of specimens were loaded until the catastrophic failure occurred by using the AGS-1000 $D^{(R)}$(Shimadzu, Japan). The result of marginal fidelities and fracture strength were statistically analyzed with the SPSS version 8.0 programs. The results of this study were as follows : 1. No significant difference was found in the mean marginal fidelities and fracture strength between the IPS Empress $2^{(R)}\;and\;In-Ceram^{(R)}$. 2. In comparison of marginal fidelities between before and after cementation, there was significant difference(P<0.05). The IPS Empress 2 system was shown in this study that had good marginal fidelities and fracture strength compared to In-Ceram ceramics. Although this system was acceptable to clinical applications, the system still has to be considered long-term researches about marginal fidelities and fracture strength due to the lack of data about the clinical researches.

• 에너지공학
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• 제15권3호
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• pp.146-153
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• 2006

중 저준위 방사성폐기물 유리화 공정에서 발생되는 분진을 제거하기 위하여 저온용융로 후단에 금속필터를 장착하여 성능시험 및 필터 적용 평가를 실시하였다. 실험결과 기존의 고온세라믹필터와 유사한 차압특성을 보였으며, 유량 $110Nm^{3}/hr$ 기준으로, 필터 자체에 의한 압력손실은 $25mmH_{2}O$, 분진 잔류층에 의한 압력손실은 $67mmH_{2}O$ 정도였다. 따라서 기저차압은 $92mmH_{2}O$ 정도임을 확인할 수 있었다. 또한 SEM-EDS 분석결과 대부분의 차압은 멤브레인층의 표면에서 발생된 것으로 판단되며, 열화현상에 의한 부식문제등도 발견되지 않았다. 따라서 금속필터의 경우 유리화설비에 적용 가능한지를 분석하고, 장기시험을 통한 충분한 검증이 필요할 것으로 판단된다.

• 대한치과의사협회지
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• 제48권9호
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• pp.680-687
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• 2010

The purpose of this study was to compare post cementation efficacy according to the different adhesive systems and cement delivery methods. A total of 40 extracted human single-rooted premolar teeth were randomly divided in four groups according to the two luting agents of Unicem applicap (3M ESPE, St. Paul, MN, USA) or Variolink II (Ivoclar Vivadent, Liechtenstein) and cement delivery methods of direct cement application or lentulo spiral application. After restoration using glass?fiber posts, the samples were embedded in acrylic resin. Three sections of 2 mm thickness were prepared from each specimen, and the post in each section was subjected to a push-out test. The data were analysed statistically at significant level of 95%. The Unicem had significantly higher push-out bond strength than Variolink and the lentulo spiral application made higher bond strength (p<0.05). Adhesive failure between cement and dentin was predominant in all groups. The Unicem of self-etch system and cement delivery using lentulo spiral showed clinically acceptable and comparable bonding strength for the fiber post.

• 한국수산과학회지
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• 제41권5호
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• pp.309-314
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• 2008

The toxicity of five species of puffer fish, Arothron firmamentum (Byeolbok), Lagocephalus gloveri (Heukmilbok), L. wheeleri (Eunmilbok), L. inermis (Minmilbok) and L. lunaris (Milbok), collected from fish markets in Korea, was determined using a mouse bioassay. In A. firmamentum, the proportion of toxic specimens containing >10 MU/g was 87.5% in the ovaries, and 10.0% in the skin; no toxicity was detected in the muscle, fin, liver, intestine and gallbladder using the mouse bioassay. The highest toxin levels were found to be 87 MU/g in the ovaries, and 13 MU/g in the skin. Toxic specimens containing >10 MU/g were not detected from samples taken from any of the organs in L. wheeleri and L. inermis. In L. gloveri, most specimens were found to be non-toxic, but toxin levels of 11-72 MU/g were detected from within the skin, fins, and intestines in one specimen. In L. lunaris, the proportion of toxic specimens was 50.0% in the ovaries, and 7.1% in the gallbladder; no toxicity was detected in the other organs by the mouse bioassay. The highest toxin levels were 75 MU/g in the ovaries, and 14 MU/g in the gallbladder. Therefore, the toxicities of edible muscle and skin in the five species of puffer fish marketed in Korea were found to be within acceptable levels for human consumption.

• 한국지반공학회지:지반
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• 제12권2호
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• pp.9-18
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• 1996

실험실에서 재 성형한 정규압밀점토에 대하여 실시된 일련의 삼축압축시험 거동결과를 등방단일경화구성모델에 의한 예측치와 비교검토한다. 이 모델사용에 필요한 열한개의 계수는 등방압밀공시체에 대한 비배수삼축압축시험 결과로부터 간단히 결정된다. 이렇게 결정된 계수를 활용한 이 모델로 이방압밀공시체를 대상으로 한 비배수삼축압축시험시의 응력-변형률 및 간극 수압의 거동이 예측된다. 또한 등방압밀공시체 및 이방압밀공시체를 대상으로 실시한 배수삼축 압축시의 응력-변형률 및 체적변형률 거동예측에도 이 모델을 적용하였다. 예측치와 시험치의 비교결과 비배수삼축압축시험의 경우는 등방압밀공시체와 이방압밀공시체 모두에 좋은 일치를 보이고 있다. 그러나 배수삼축압축시험의 경우는 초기 체적변형률의 예측치가 시험치보다 약간 작게 나타나다가 파괴점에 근접함에 따라서는 예측치가 시험치보다 커지는 경향을 보이고 있다. 그러나 전반적인 응력 -변형률거동은 좋은 일치를 보이고 있음을 알 수 있다. 따라서, 본 연구결과 이 모델은 정규압밀점토의 거동예측에 적용성이 충분히 있다고 생각된다.

• Journal of Korean Neurosurgical Society
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• 제29권12호
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• pp.1577-1583
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• 2000

Objectives : Among the various types of minimally invasive spine surgeries, thoracoscopic surgery is becoming more widely accepted and increasingly utilized. This report delineates our clinical experience using thoracoscopy to resect herniated thoracic discs in 16 patients who suffered from myelopathy or intolerable radiculopathy. Patients and Methods : Between Mar. 1997 and Sep. 1999, 16 consecutive patients underwent thoracoscopic discectomy for treatment of herniated thoracic discs. There were 12 men and 4 women(mean age 43.5 years ; range 18-61 years). Eleven patients presented with myelopathic signs and symptoms from spinal cord compression and 5 patients had incapacitating thoracic radicular pain without myelopathy. The surgical level was varied between T3 and T12. The pathology of specimen were 11 hard discs and 5 soft discs herniations. Thoracoscopic techniques were performed with long narrow spine instruments and high speed drill through 3 or 4 ports under one lung ventilated general anesthesia. During the operation three patients were converted to open thoracotomy due to intolerable one lung ventilation, excessive bleeding and inadequate operation field. The mean operation time was 264min.(range : 100-420min.), and postoperative mean admission period was 11 days. Results : Clinical and neurological outcomes were good in all patients(mean follow-up period 20 months). Among the eleven myelopathic patients, 8 improved neurologically, and 3 stabilized. Among the five radiculopathic patients, 4 recovered completely and no patient had worsened. Postoperative complications were pleural effusion in one case, intercostal neuralgia in one, delayed hemopneumothorax in one, prolonged air leakage in one and pneumonia in one case. Conclusions : Thoracoscopic discectomy needs a steep learning curve to be familiar to anatomical space and handling of endoscopic instruments. However, it is technically feasible and can be effectively performed with acceptable results.

• 대한치과보철학회지
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• 제42권5호
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• pp.544-555
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• 2004

Statement of problem: Shade selection has traditionally been accomplished by visual examination, which is particularly relevant to the shade selection of anterior teeth, but the subjective nature of visual analysis can lead to errors in shade matching. Recently shade selection systems have been developed to provide a more objective and scientific approach to understanding and clarifying shade selection. Purpose : The purpose of this study was analysis of various shade analyzing equipment with the goal of providing a more objective shade selection. Materials and method: Visual shade matching system selection(Vita Lumin Vacuum shade guide, Vitapan 3D Master shade guide) and mechanical shade matching method($ShadeEye^{(R)}$-EX Chroma Meter, $Shadescan^{TM}$ System) used for this study. The shade guide tap specimens for 10 extracted maxillary anterior teeth were produced by selecting shades using each shade matching system. The accuracy of the selection of shades for the teeth and fabricated specimens were evaluated by analyzing the calculated shade difference(${\Delta}E^*$), using a spectrophotometer and calculating the output of value $L^*,\;a^*,\;b^*$. Results and conclusion: The results show that the average ${\{Delta}E^*$ value (difference of shade) of the shade tap specimens to the actual specimen decreased in the following order: Vita Lumin Vacuum Shade Guide(VL), $ShadeEye^{(R)}$-EX Chroma Meter(SE) Vitapan 3D Master Shade guide(V3), and $Shadescan^{TM}$ System(55) : and that there are significant statistical differences between the VL and SS (p<0.05). In the analysis of the ${\Delta}E^*$ (difference of shade) value,40% of the VL group was found to be less than 3.3 (limit value of shade tap specimens clinically acceptable), 60% in the V3 group, 50% in the SE group, and 80% in the SS group.

• 대한치과보철학회지
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• 제44권3호
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• pp.275-283
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• 2006

Statement of problem. There have been many studies about marginal discrepancy of single restorations made by various systems and materials. However most of the statistical inferences are not definite because of sample size, measurement number, measuring instruments, etc, and there have been few studies about the marginal fit of the Digident CAD/ CAM zirconia ceramic crowns. Purpose. The purpose of this study was to compare the marginal fit of the anterior single restorations made by using the Digident CAD / CAM zirconia ceramic crowns with metal-ceramic restorations and to obtain more accurate information by using a large enough sample size and by making sufficient measurements per specimen. Material and Methods. The crowns were made from one extracted maxillary central incisor pre-pared with a 1mm shoulder margin and $6^{\circ}$ taper walls by milling machine. The in vitro marginal discrepancies of the digident CAD / CAM zirconia ceramic crowns and control groups(metal ceramic crowns) were evaluated and compared. Twenty crowns per each system were fabricated. Measurements of a crown were recorded at 50 points that were randomly selected for marginal gap evaluation. Parametric statistical analysis was performed for the results. Conclusion. Within the limitations of this in vitro study, the following conclusions were drawn: 1. Mean gap dimensions and standard deviations at the marginal opening for maxillary incisal crowns were $88{\pm}10{\mu}m$ for the control (metal-ceramic crowns), $92{\pm}4{\mu}m$ for Digident CAD / CAM zirconia ceramic crowns. 2. Marginal gap between Digident CAD / CAM zirconia ceramic crowns and metal ceramic crowns did not show significant difference (P>.05). 3. The Digident CAD/ CAM zirconia ceramic crowns and metal ceramic crowns showed clinically acceptable marginal discrepancy.

• 대한치과보철학회지
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• 제34권4호
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• pp.657-664
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• 1996

The purpose of this study was to compare the dimensional stability, compression resistance, elastic recovery and surface hardness of elastomeric interocclusal recording materials. Five commonly used elastomeric interocclusal recording materials(Ramitec, Regisil, Blue-Mousse, Stat-Br, Coltoflax) were selected for this study. According to ADA specification No. 19, two types of specimen were fabricated. Cylinder type specimens were used to test compression resistance and elastic recovery and plate type specimens were used to evaluate dimensional stability and surface hardness. Paired t-test was applied to detect significance among the occlusal registration materials. The obtained results were as follows: 1. There were statistical difference in dimensional stability between the elastic interocclusal recording materials. The dimensional stability of silicone was higher than that of polyether tested(p<0.05). 2. Coltoflax was significantly less resistance to compression than the other elastic interocclusal recording materials(p<0.001). 3. The elastic recovery capacity of Blu-Mousse and Stat-Br is better than that of Coltoflax (p<0.01). 4. The surface hardness of Coltoflax was lower than that of Blu-Mousse and Stat-Br(p<0.05). 5. The percentage dimensional change of alll materials was acceptable according to the limid of 0.5% suggeted by ADA specificatin No. 19.