• 대한방사선기술학회지:방사선기술과학
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• 제19권1호
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• pp.41-49
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• 1996

We have been used super sensitive screen/film system which is thought to be the limit of sensitivity, however, we think this method is not satisfactory. As a general radiographic rule, reduction of exposure is inconsistent with improvement of image quality, but it is necessary to challenge this rule to get better method. We tried air gap method for minimal diffuse lung shadow which is difficult to find out by our routine method. As a result, air gap method with super sensitive screen/film system(SRO 1000/TMH) showed lower exposure dose, 50% of our routine system(SRO 750/SRH with grid), and better image quality for pulmonary pattern in the lower lung field.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.176-181
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• 2017

PURPOSE. The purpose of this study was to evaluate the marginal and internal gaps of Ni-Cr and Co-Cr copings, fabricated using the dental ${\mu}-SLA$ system. MATERIALS AND METHODS. Ten study dies were made using a two-step silicone impression with a dental stone (type IV) from the master die of a tooth. Ni-Cr (NC group) and Co-Cr (CC group) alloy copings were designed using a dental scanner, CAD software, resin coping, and casting process. In addition, 10 Ni-Cr alloy copings were manufactured using the lost-wax technique (LW group). The marginal and internal gaps in the 3 groups were measured using a digital microscope ($160{\times}$) with the silicone replica technique, and the obtained data were analyzed using the non-parametric Kruskal-Wallis H test. Post-hoc comparisons were performed using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The mean (${\pm}$ standard deviation) values of the marginal, chamfer, axial wall, and occlusal gaps in the 3 groups were as follows: $81.5{\pm}73.8$, $98.1{\pm}76.1$, $87.1{\pm}44.8$, and $146.8{\pm}78.7{\mu}m$ in the LW group; $76.8{\pm}48.0$, $141.7{\pm}57.1$, $80.7{\pm}47.5$, and $194.69{\pm}63.8{\mu}m$ in the NC group; and $124.2{\pm}52.0$, $199.5{\pm}71.0$, $67.1{\pm}37.6$, and $244.5{\pm}58.9{\mu}m$ in the CC group. CONCLUSION. The marginal gap in the LW and NC groups were clinically acceptable. Further improvement is needed for CC group to be used clinical practice.

• 치위생과학회지
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• 제15권5호
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• pp.536-541
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• 2015

본 연구에서는 CAD/CAM 시스템을 이용하여 제작한 코발트-크롬 주조 금속 코핑과 코발트-크롬 소결 금속 코핑의 변연 및 내면 적합도를 비교 평가하여 다음과 같은 결론을 도출하였다. 코발트-크롬 금속 코핑의 변연 및 내면 적합도를 비교 평가는 기존의 주조방식인 CCM 그룹보다 소결과정만으로 제작한 CSM 그룹이 전반적으로 모두 우수하였다. 또한 CSM 그룹의 변연 적합도는 임상적으로 허용할 수 범위인 $120{\mu}m$ 이내 존재하였다는 결과를 통해서 그동안 매몰, 소환, 주조인 복잡한 과정을 거치면서 보철물의 오차가 발생 하였으나 소결과정만으로 공정 과정의 오차를 줄임으로써 완성도 높은 코발트-크롬 금속 코핑 제작이 가능하다고 생각된다.

• International Journal of Clinical Preventive Dentistry
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• 제14권4호
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• pp.247-255
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• 2018

Objective: Osseointegration is essential process for successful implants and effects to implant in long term, therefore, passive fitness of good prosthesis is necessary. To make a good prosthesis, at first it should be done a sectioned casting and then joined method of sectioned casting body is recommended. Methods: In this study, to provide the fundamental data on stable connection method for successful implants, the author tested fitness of casting body, and compared difference between gas soldering technique and laser welding technique. Results: In fitness test of 2 abutment (test A, C), gas soldering group's fitness in the opposite part of connection was worse than laser welding group. In fitness test of 3 abutment (test B, D), gap distance was increased both in gas soldering technique and laser welding technique. Gap distance at the connecting part and the opposite part of the abutment in gas soldering technique was worse than laser welding technique and the more additional abutment, the worse gap distance in gas soldering technique. In fitness test of 3 abutment (test B, D), there's little variation in No. 2 abutment when connecting soldering process was done and there's little influence on already soldered connection part when the additional soldering connection was done. Conclusion: On weak loading condition and the part which is needed an accuracy, laser welding technique is more effective and on long-span prosthesis and frequent chewing loading part, laser welding technique is recommended first and applying additional gas soldering technique would be better for making much more successful prosthesis.

• 환경영향평가
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• 제21권5호
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• pp.631-648
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• 2012

The integrative ecological approaches of chemical assessments, physical habitat modelling, and multi-metric biological health modelling were applied to Gwanpyeong Stream within Gap-Stream watersheds to evaluate environmental impacts on the constructions of residential and commercial complex. For the analysis, the surveys conducted from 45 sites of reference streams within the Gap-Stream watershed and 3 regular sites during 2009 - 2010. Physical habitat health, based on the habitat model of Qualitative Habitat Evaluation Index(QHEI) declined from the headwaters(good - fair condition) to the downstream(poor condition). Chemical water quality, based turbidity and electric conductivity(EC), was degraded toward to the downstream, and especially showed abrupt increases, compared to the values of control streams(CS). Also, concentrations of chlorophyll-a in the downstreams were greater compared to the control stream(CS), indicating an eutrophication. Biological health conditions, based on the Index of Biological Integrity(IBI) using fish assemblages, averaged 19.3 which is judged as a fair condition by the biological criteria of the Ministry of Environment, Korea. The comparisons of model metric values in sensitive species and riffle-benthic species on the Maximum Species Richness Line(MSRL) of 45 reference streams indicated a massive disturbances in all sampling locations. Also, tolerance guild and trophic guild analyses suggest that dominances of tolerant species and omnivores were evident, indicating a biological degradation by habitat disturbances and organic matter pollutions. There was no distinct longitudinal variations of IBI model values from the headwater to the downstream in spite of slight chemical and habitat health gradients among the sampling sites. Overall, integrative ecological health(IEH) scores, based on the chemical, physical, and biological parameters, were low compared to the 45 reference streams due to physical and chemical disturbances of massive constructions of the residential and commercial complex. This stream, thus showed a tendency of typical urban streams which are disturbed in the chemical water quality, habitat structures, and biological integrity. Effective stream management plans and restoration strategies are required in this urban stream for improving integrative stream health.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 2004년도 제3회 식품안전의 날 기념 학술 세미나
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• pp.259-259
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• 2004

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2004년도 춘계학술대회
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• pp.118-118
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• 2004

• 한국치위생학회지
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• 제8권4호
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• pp.141-151
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• 2008

The purpose of this study was to examine the oral health awareness and oral health care of health-related and health-unrelated majors in an attempt to stress the importance of oral health education and boost the efficiency of oral health care. The subjects in this study were 363 college students. Out of the selected students, 174 were health-related majors, and 189 weren't. After a survey was conducted, the collected data were analyzed for the purpose of comparison, and the following findings were given: 1. Concerning daily mean toothbrushing frequency, the largest number of the male students who accounted for 55.2 percent brushed their teeth once a day on average, and the greatest number of the female students who represented 52.9 percent did that twice a day. As for the influence of their major, the largest group of the health-related majors who numbered 89(51.1%) brushed their teeth twice a day, and the greatest group of the health-unrelated majors who numbered 93(49.2%) did that once a day. The gaps between them were statistically significant(p<0.05). 2. As to the length of toothbrushing time by gender, it took more than two or three minutes for the largest groups of the male and female students that respectively numbered 96(76.8%) and 184(77.3%) to do toothbrushing(p<0.01). The greatest groups of the male and female students that respectively numbered 72(57.6%) and 183(76.9%) brushed their teeth after meals. 3. In regard to oral hygiene supplies, the largest groups of the health-related and health-unrelated majors that respectively numbered 78(44.8%) and 115(60.8%) had chewing gum and candy with them. As to the use of oral hygiene supplies, 99 health-related majors(56.9%) and 133 health-unrelated majors(70.4%) didn't put oral hygiene supplies to use. Thus, the use of oral hygiene supplies was statistically less common among the health-unrelated majors, and the gap between the two was significant(p<0.01). 4. As for health-related concern by gender, the largest group of the male students that numbered 56(44.8%) showed the most interest in preventing dental caries, and the greatest group of the female students that numbered 103(43.3%) were most concerned about tooth whitening. The gap between the male and female students was statistically significant(p<0.05), but the track of their major made no statistically significant difference to that. 5. Regarding the experience and awareness of scaling, the largest number of the students never got their teeth scaled regardless of gender and major, and the greatest group didn't care about scaling irrespective of gender and major, either, though they considered it advisable to do.

• 치위생과학회지
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• 제14권2호
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• pp.207-213
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• 2014

본 연구는 국민건강영양조사 5기(2010~2012년) 원시자료를 이용하여 사회경제적 수준에 따른 주관적 구강건강 상태의 차이와 관련성을 분석하기 위하여 실시되었다. 주관적 구강건강 수준을 '좋다'와 '나쁘다'로 분류하여 사회경제적 수준이 건강불평등에 미치는 요인을 분해하여 다음과 같은 결과를 얻었다. 주관적 구강건강 상태는 남자에 비해 여자가 구강건강을 좋지 않다고 인식하는 것으로 나타났으며, 연령 증가 시 본인의 구강건강을 나쁘게 인식하는 것으로 분석되었다. 또한 교육수준이 낮을수록, 가구소득이 낮을수록 주관적 구강건강상태를 나쁘다고 자가 평가하는 경향을 보였다. 로지스틱회귀분석을 활용하여 주관적 구강건강 상태에 대한 영향 요인을 분석한 결과 사회계층에 따른 건강상의 차이는 남자에 비해서 여자에서 자신의 구강건강수준을 더 건강하게 인지할 확률이 높아지고 있으며 교육수준이 높을수록 건강하게 인지할 가능성이 높았다. 소득수준에 따른 주관적 건강수준에 대한 인식의 격차는 소득증가에 따라 더 심화되는 것으로 나타났다. 이상의 연구결과를 살펴보면 구강건강에 사회계층별 불평등은 존재하는 것으로 나타났다. 전체 국민의 구강건강을 증진하는 사업은 물론 사회 양극화에 따른 사회계층별 구강건강의 격차를 해소하기 위해 상대적으로 격차가 큰 취약계층에 적절한 정책적 지원이 고려되어야 할 것으로 사료된다.

• 디지털융복합연구
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• 제14권1호
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• pp.321-326
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• 2016

치주질환은 치아주위 조직에 발현된 염증성 질환이다. 전염증성 사이토카인인 $TNF-{\alpha}$는 국소적인 염증이나 전반적인 염증과 관련이 있는 것으로 알려져 있다. 본 연구의 목적은 한국인에서 TNF 유전자 다형성과 전반적 급진성 치주염 간의 관계를 알아보고자 하였다. 연구대상은 실험군이 60명, 대조군이 81명 이었다. 협측에서 DNA를 채취하여 각 제한효소를 이용한 PCR-RFLP에 의해 $TNF-{\alpha}-308$과 -238을 측정하였다. 급진성 치주염 환자에서 $TNF-{\alpha}-308$ 유전자형은 A/A 3.2%, A/G 38.7% 그리고 G/G 82.35%가 나타났으며 대조군에서는 각 9.1%, 45.5%, 45.5%로 유의한 차이를 보이는 결과이다. $TNF-{\alpha}-238$의 대립유전자 2의 빈도는 실험군에서 67.6%, 대조군에서 72.2%로 유의한 차이를 보였다. 이러한 결과에 따르면 $TNF-{\alpha}-308$과 -238의 유전자다변성은 한국인의 급진성치주염과 연관이 있을 것으로 생각된다.