• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.245-251
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• 2013

Purpose: This study was conducted to compare in vivo biofilm formation on titanium surface and zirconia surface. Materials and methods: For biofilm formation on titanium and zirconia in oral cavity, after producing oral appliances using acrylic resin and orthodontic wire tailored to 9 subjects, we made titanium and zirconia specimens ($6mm{\times}6mm{\times}2mm$), fixed them on oral appliances and maintained them in oral cavity of test subjects for 24 and 72 hours. Test subjects who have equipped two pairs of specimens maintained oral hygiene not by using toothpaste but only by tooth brushing. After 24 and 72 hours, we removed and observed specimens through scanning electron microscopy (SEM). Results: Biofilm formation showed large deviation depending on individuals. For formation comparison between titanium and zirconia for 24 hours, zirconia showed less biofilm formation than titanium. Biofilm formation showed large deviation depending on individuals. As for formation comparison between zirconia and titanium, the degree of biofilm formation in zirconia was less than it was in titanium after a lapse of 24 hours. The result of biofilm formation in 72 hours trial show that zirconia has an inclination to formate less biofilm than it was in titanium. Conclusion: Based on the above results, we can conclude that early biofilm formation in oral cavity was influenced by difference of abutment materials.

• Journal of Ginseng Culture
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• v.2
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• pp.17-26
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• 2020

Ginseng, also known as Insam, has solidified its status as one of the supreme drugs classified as life time expansion drug since ancient times and was used as a panacea based on its pharmaceutical effectiveness. The demand for ginseng rapidly increased as the demand for ginseng, which targeted only noble class people, expanded to other social class people. Accordingly, the wild ginseng supply reached its limit due to the extinction caused by indiscriminate harvesting and the difficulty of harvesting, and thus the ginseng supply method shifted to the cultivation of high-priced ginseng rather than complicated wild ginseng foraging. Although the timing of ginseng cultivation (also called gasam) in Korea has been studied, the research on the first cultivation area has not been reported yet. In this study, we critically reviewed Korea's first ginseng cultivation site by arranging data related to ginseng cultivation, and the historical data cited here include Joseon Wangjo Sillog (The Annals of Joseon Dynasty), Imwon Gyeongjeji (The Mid-19 Century Encyclopedia Koreana on Rural Living, Edible plants and Herb Volumes), Oju Yeonmun Jangjeon Sango (An Encyclopedic Writing during the Latter Half Period of the Joseon Dynasty), Junggyeongji (The Junggyeong Town Chronicle), Jeungbo Munheon Bigo (The largest encyclopedia of Joseon Dynasty), Insamsa (The Ginseng History) and etc. As a result of data assortment and critical review, the first ginseng plantation in the Joseon Dynasty resulted in the Yeongnam region, and in Yeongnam region, I have no choice but to conclude that it is Punggi-myeon (currently Punggi-eup, Yeongju-si, Gyeongbuk).

• The Journal of Korean Society for School & Community Health Education
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• v.9 no.2
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• pp.105-118
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• 2008

Objectives: This study was performed in order to figure out oral health knowledge level of home room teachers of elementary schools in Daegu area. This study was conducted from March through May 2008. Methodology: A total of three hundred and ten (43 male teachers and 267 female teachers) home room teachers of elementary schools were surveyed. The collected data were analyzed by X2 test and one way ANOVA test by using SPSS 11.0 program. Results: Most oral health knowledge was obtained from dental clinics (45.8%) and mass media and books (40.0%). Many respondents reported that the main purpose of oral hygiene was prevention of periodontal diseases. The highest number of respondents reported that fluoridated tooth paste was the best for fluoride effects on teeth. 56.7% of the respondents said that they visited periodically dental clinics for dental caries prevention. The respondents did not have much knowledge about the importance of fluoride in dental caries. Many respondents did not know that the plaque is the main cause of periodontal diseases. Conclusion: Effective oral health education program should be prepared for the elementary school teachers because their knowledge levels of oral health is not sufficient for students.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.118-128
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• 2001

This study was performed to evaluate the toothbrush abrasion characteristics of seven commercially available light-cured cervical restorative materials one resin-modified glass-ionomer material(Fuji II LC) three polyacid-modified composites(Compoglass, Dyract, F2000), and three light-cured composites(Heliomolar, Palpique Estelite, UniFil F). All samples were stored in distilled water at $37^{\circ}C$ for 10 days. 2.0N of weight was loaded during the test and the abraded surfaces were examined with profilometer and SEM after 100,000 cycles. The results obtained were summarized as follows; 1. The highest hardness value of 79.7 was observed in the FT group and the lowest value of 20.0 was observed in the HM group. Results of Tukey test showed that an overall significant difference was indicated except the CG and DR groups(p<0.05). 2. The highest surface roughness was observed in the FL group and the lowest was observed in the UF group. Results of Tukey test showed the significant difference between the FL or FT and UF groups(p<0.05). 3. Statistically higher abrasion and surface roughness were observed for the dentifrice of paste type, Perio A+, than for that of gel paste type, Tom & Jerry. 4. The surface roughness values increased on the abraded surfaces because of the protrusion of filler particles due to selective removal of matrix resin.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.52-56
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• 2012

The aim of this study was to evaluate the antimicrobial effect of carvacrol against periodontopathic and cariogenic bacteria and its cytotoxicity in human oral tissue cells. We tested their antibacterial properties against mutans streptococci and five major periodontopathic bacterial species involved in periodontal disease. The antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The cell viability of carvacrol on normal human gingival fibroblast (NHGF) cells was tested by metyl thiazolyl tetrazolium assay. The data showed that carvacrol had remarkable antimicrobial effect on tested bacteria with a MIC and MBC values ranged from 16 to $128{\mu}g/ml$ and from 32 to $128{\mu}g/ml$, respectively. In cell toxicity studies, carvacrol had significantly decreased cell viability when NHGF cells were treated at $128{\mu}g/ml$. These findings suggest that carvacrol has a strong antimicrobial activity against periodontopathic and cariogenic bacteria. However, in order to use it as a component of gargling solution or toothpaste, its concentration should be below $64{\mu}g/ml$ and other compounds having an antimicrobial activity against periodontopathic and cariogenic bacteria should be used together.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.737-749
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• 1999

Recently many researches on plaque removal effect and therapeutic effect of toothpaste containing natural medicines are being studied in early periodontal diseases. The purpose of this study is to examine the clinical and microbiological effect of toothpaste containing natural medicines such as camomile, rhatany, myrrh，sage oil, glycyrrhetinic acid and vitamin E. Sixty three subjects with gingivitis were divided into an experimental group which performed normal oral hygiene procedure with toothpaste containing natural medicines and vitamine E and a control group which also performed normal oral hygiene procedure with Syrinmed? toothpaste without containing herbal extracts and vitamine E. At the baseline, 2 weeks, and 4 weeks, subjects were analyzed for clinical study and microbiological study. After 2 weeks and 4 weeks use of their respective toothpastes, statistically significant decreases of gingival index, plaque index, and bleeding index were shown in both the control and the experimental group. The degree of decrease was more significant in the experimental group than the control group. A statistically significant decrease of pocket depth, and gingival crevicular fluid were shown in both the control and lie experimental group. A statistically significant increase of cocci was shown in both the control and the experimental group, the degree of increase was more significant in the experimental group than control group. A statistically significant decrease ofnon-motile rods, and motile rods were shown in both the control and the experimental group, the degree of decrease was more significant in the experimental group than the control group. Spirochetes increased weakly in both the control and the experimental group but a statistic significance was not shown. A statistically significant decrease of anaerobic bacteria, aerobic bacteria, and black pigmented Bacteroides were shown in both the control and the experimental group. These results indicate that the use of toothpaste containing natural medicines is effective in the prevention and the treatment of periodontal diseases.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.163-176
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• 2005

3개월 동안 사용한 마모된 칫솔의 마모 정도와 양상을 관찰하고, 새 칫솔과 마모된 칫솔의 잇솔질 전 ${\cdot}$ 후 치태제거효율을 single-use design으로 비교 ${\cdot}$ 평가하여 3개월 주기의 칫솔 교체 주기의 근거를 임상적으로 확인 해보고자 하였다. 치주적으로 건강한 치과 대학생 42명을 대상으로 설문지를 통해 잇솔질 습관을 조사하고, 3개월간 동일한 칫솔과 치약을 사용하게 하였다. 3개월 후 피시험자를 무작위로 두 군(I, II)으로 나누고, 치석제거술을 시행한 뒤 2주후에 내원하도록 하였으며 내원 전 48시간동안은 잇솔질을 하지 않도록 지시하였다. 2주후 I군은 새 칫솔을, II군은 마모된 칫솔을 사용하도록 하였으며 잇솔질 전 ${\cdot}$ 후에 각각 구강 내를 erythrosin으로 염색한 후 6개의 Ramfjord 치아의 plaque score를 Patient Hygiene Performance (PHP) index로 측정하였다. 2주간의 washout period 후에 다시 치석제거술을 시행한 뒤, I군이 마모된 칫솔을, II군은 새 칫솔을 사용하게 하여 동일한 방법으로 PHP index를 각각 측정하였다. 마모된 칫솔은 수거하여 brushing surface area의 면적으로 마모도를 평가하였다. 결과는 paired t-test와 Pearson's correlation analysis로 통계처리 하였다. 2명이 탈락하였고 잇솔질 전 ${\cdot}$ 후에 대한 전체 부위, 치간 부위, 변연치은 부위의 plaque score는 두 칫솔 모두 통계학적으로 유의성 있게 감소하였으며 (p<0.0001), 두 칫솔을 비교한 경우에는 새 칫솔이 마모된 칫솔보다 치태 감소량이 통계학적으로 유의성 있게 많았다 (p<0.0001). 칫솔의 마모도는 평균 50.6% 증가하였으며, 마모도 증가에 따른 치태 감소량에는 직선적인 상관관계가 있었으나 통계학적인 유의성은 없었다. (전체 부위 r=-0.58, p=0.72 / 변연치은 부위 r=-0.50, p=0.76). Single-use design에서 3개월 동안 마모된 칫솔은 치태제거 능력에 있어서 새 칫솔보다 덜 효율적이였다. 칫솔의 마모도는 구강 위생 관리에 영향을 미치는 중요한 요인이며, 마모된 칫솔은 정기적인 교체가 요구된다. 또한, 치간 부위를 포함한 변연치은 부위의 치태를 정확하게 평가할 수 있는 치태지수에 대한 연구가 필요하겠다.

• Journal of Korean society of Dental Hygiene
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• v.14 no.1
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• pp.101-108
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• 2014

Objectives : The purpose of this study was to evaluate the tooth whitening effect of 0.74% and 2.80% hydrogen peroxide toothpastes and safety on tooth and gingival tissue. Methods : Toothpastes containing 0.74% and 2.80% hydrogen peroxide were evaluated. In in-vitro test, some additives (sodium metaphosphate, sodium pyrophosphate and titanium dioxide) were added to the toothpastes. Hydroxyapatite specimens (HAPs) were made and stained using modified Stookey's methods. HAPs were treated for 1 hour at shaking incubator and brushed for 1,000 times as 250 gF with each diluted toothpaste. Before and after color was measured by colorimeter. Using double blind method, 99 Korean with natural maxillary anterior teeth were selected and the initial brightness (baseline) was measured by SHADEEYE-EX. Based on this measurement they were crossly distributed into control group (0% hydrogen peroxide), test 1 (0.74% hydrogen peroxide) and test 2 (2.80% hydrogen peroxide). After 2 weeks, people of each group were provided toothpaste and told to use 3 times a day right after every meal for 3 minutes. The brightness of teeth was measured 3 times for every one month. Results : ${\Delta}L$ was statistically significant among three groups in shaking test. ${\Delta}L$ of two test groups was statistically significant compared with control group but not between each test group in brushing test. After using toothpaste for 3 months, test 1 group and test 2 group were 15.89% and 31.23% more whitened compared with control group respectively (p<0.05). Rate of more whitened person of each test group was 24.2% and 40.5% more than control group respectively (p<0.05). There was no difference in the hypersensitivity during 3 months using toothpastes and no side effect on teeth or gums. Conclusions : Toothpastes containing 0.74% and 2.80% hydrogen peroxide showed tooth whitening effect and both were safe enough to use for tooth whitening.

• Journal of Welding and Joining
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• v.15 no.6
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• pp.24-31
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• 1997

2매의 금속을 맞대어 그 한 쪽에 접촉면과 평행하게 고주파진동을 가하면 단 시간에 접합된다. 이공정을 초음파 용접이라고 하며 그 물리적인 본질은 아직 불분명 하지만, 첫째로는 강한 마찰에 의해 금속 자유면의 산화물층이 제거되기 때문이라는 점과 둘째로는 마찰에 의해 금속 표면이 강하게 가열되어 이에 따른 연화에 의해 접합 이 된다고 하는 점이다. 그러나 이와 같이 가열된다고 하더라도 가열은 표면부에만 국한되고 다른 부분은 가열되지 않는다. 따라서 초음파용접은 냉간접합이라고도 한다. 또 가압력과 진동에 의한 힘이 동시에 작용하기 때문에 용접할 면을 미리 청정하게 할 필요는 없고 용접전의 단계에서 자연적으로 청정화가 이루어진다고 하는 사실이 간접 적으로 증명되고 있다. 초음파 용접(Ultrasonic welding)의 특징을 요약하면 고상용접 의 일종으로서 용접중에 국부적으로 고주파 진동에너지와 압력을 가하여 용접하는 방법이다. 이 때 모재를 용융시키지 않고 건전한 야금학적 결합부가 얻어진다는 데에 큰 특징이 있다. 또한 초음파용접은 다른 용접법에 비해 경제성이 매우 높고, 초음파 용접에 필요한 출력이 전기아크 용접에 필요한 출력의 5 - 10%로 충분한 경우가 많다. 초음파 용접은 통상의 방법으로는 용접하기 어려운 동종 금속이나 이종 금속의 용접에 널리 사용된다. 이 용접법은 반도체, 미세회로, 전기 접점의 형성에 대한 생산기술 로서 사용되고 있는데 소형 모터, 알루미늄 박의 가공, 알루미늄 합금의 조립 등에 이용되고 있다. 한편 최근에는 자동차, 우주항공산업 분야의 구조제 용접용으로도 채용되고 있다.출함이 바람직하다.분비되는 배설-분비 항원의 자극과 깊은 관계가 있음을 알 수 있었다.넌트 명세서를 대한 XML DTD(Document Type Definition)를 정의하고, HTML 기반 검색 방법과 XML 기반 검색 방법에 대한 컴포넌트 검색 성능을 비교한다.따라 NO 생산 및 세포독성이 증가하였고. NO 생산을 저하시키는 약제들은 활성화된 복강 대식세포 및 RAW264.7 세포에 의한 질편모충에 대한 세포독성을 현저히 감소시키는 것으로 보아 NO는 질편모충에 대한 대식세포의 숙주 방어기전에서 중요한 역할을 감당할 것으로 생각된다.nction index) 와 최대개구시 동통의 정도는 시술전과 시술 4주후간에 유의한 차이가 관찰되었다.피부온도는 검사자간에는 특정부위에 따라 다소 차이가 있을 수 있으나 일반적으로 높은 재현성을 보여줌으로서 향후 교근 및 측두근의 임상연구 평가에 피부온도조사는 도움이 되리라 사료된다. lactobacilli의 양은 peroxidase system을 함유하거나(p < 0.01) 함유하지 않은(p < 0.05) 치약을 사용한 군 모두에서 양치전에 비해 유의성있게 감소하였다. 6. 양치후 30분에 채취한 구강건조증 환자의 자극성 전타액내 S. mutans 양은 peroxida system을 함유한 세치제를 사용한 군에서 대조군에 비해 유의성있게 낮았다(p < 0.05). 7. 양치후 30분에 채취한 구강건조증 환자의 자극성 전타액내 lactobacilli양은 peroxidase system을 함유한 세치제를 사용한 군에서 대조군에 비해 상대적으로 낮게 나타났으나(p = 0.067)

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.1
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• pp.31-37
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• 2015

The recent long-term economic recession and business depression are constantly increasing the occurence of the five major crimes(murder, robbery, rape, theft, violence). When looking into the previously-analyzed characteristics of how the five major crimes are committed, this study understands that the crimes mostly occur in these crime-ridden areas of poor public order and security and, in order to decrease the crime rates of the crime-prone areas, any relevant fields have been emphasizing the application of CPTED. In the light of that, referring to CPTED surveillance factors and the current crime rate data, the study presented ways to help the relevant fields draw up a crime-prone area grade map. In particular, the security center among monitoring elements was visualized by dividing it into point patrol and directed patrol and by dividing it into 3 steps monitoring levels with CCTV and street lights. In addition, we checked the crime rate by zoning through crime statistics occurred in the research areas and established a crime status map. We estimated the weight through AHP analysis on the built monitoring elements and the zoning of the occurred areas, as a result of making a map vulnerable to crime by monitoring steps by overlapping each element, we were able to confirm that 60% of theft, 52% of violence and 33% of rape in the 1st grade area were reduced compared to the 1st step in monitoring Step 3.