• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.405-417
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• 2010

Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.420-430
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• 2008

Statement of problem & Purpose: Articulators are very important for education and overall clinical situation in the field of prosthodontics, however preexisting articulators are designed and built based on maxillofacial structures and mean values of mandibular movement of Western people. Purpose of this research is to find out a adequate basis for applicating these articulators, presently used for clinical education, for Korean. Material and methods: 59 Korean adults (41 males, 18 females), aged between 24 to 41, where selected for this study. Two pairs of both maxillary and mandibular models were made for each examinee. These models where attached to both KaVo PROTARevo 7 and Hanau Modular semiadjustable articulators by using facebow transfer, than sagittal condylar inclination, occlusal plane inclination and position of mandibular on the articulator where measured. Result and conclusion: 1. Mean sagittal condylar inclination for KaVo PROTAR semiadjustable articulator was $33.75^{\circ}$(standard deviation $12.46^{\circ}$) meanwhile Hanau Modular semiadjustable articulator showed $40.72^{\circ}$(standard deviation $12.09^{\circ}$) for mean sagittal condylar inclination. 2. Mean occlusal plane inclination for KaVo PROTAR semiadjustable articulator was $-2.76{\circ}$(standard deviation $3.63^{\circ}$) meanwhile Hanau Modular semiadjustable articulator showed $11.87^{\circ}$ (standard deviation $3.63^{\circ}$) for mean occlusal plane inclination. 3. On the average center of the mandibular dentition were in the range of 5 to 7 mm of the central position of the articulator. Both anterior and posterior dentition were positioned at the center of the articulator vernacularly for KaVo PROTAR semiadjustable articulators, meantime for Hanau Modular semiadjustable articulator, anterior dentition was positioned 5 mm downwards and 3mm upwards for posterior dentition from vertically central position of the articulator.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.359-371
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• 2008

Purpose: The purpose of this study was to investigate the stress distribution in mandibular implant overdentures with telescopic crowns compared to bar attachment. Material and methods: Three-dimensional finite element models consisting of the mandibular bone, 4 implants, and primary bar-splinted superstructure or secondary splinted superstructure with telescopic crowns were created. Vertical and oblique loads were directed onto the occlusal areas of the superstructures to simulate the maximal intercuspal contacts and working contacts such as group function occlusion. Maximum stress and stress distribution were analysed in mandibular bone, implant abutments, and superstructures. Results: 1. In comparison of von Mises stress on mandibular bone, telescopic overdenture had a little lower stress values in vertical load and working side load except oblique load. In the mandible, the telescopic overdenture distributed more uniform stress than the bar overdenture. 2. In comparison of von Mises stress on implant abutments, telescopic overdenture had much lower stress values in all load conditions. In implant abutments, the telescopic overdenture distributed stress similar to the bar overdenture. Stress was concentrated on the distal surfaces of the posterior implant abutments in both mandibular overdentures. 3. In comparison of von Mises stress on superstructures, the telescopic overdenture had much more stress values in all load conditions. However, the telescopic overdenture distributed more uniform stress on superstructure than the bar overdenture. In the bar overdenture, stress was concentrated on each cental area of bar structures and connected area between implant abutments and bar structures. Conclusion: In the results of this study, the telescopic overdenture had lower stress values than the bar overdenture in mandibular bone and implant abutments, but more stress values in superstructures. However, if optimal material was selected in making superstructures, the telescopic overdenture was compared to the bar overdenture in stress distribution.

• Journal of the korean veterinary medical association
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• v.44 no.9
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• pp.803-818
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• 2008

동물의 결핵은 Mycobacterium bovis의 감염에 의한 만성 소모성 질병이며 인수공통전염병이다. 동물로부터 사람으로의 결핵 전염은 생유 섭취하던 시대에 상당히 많이 보고되었다. 우유의 살균처리와 소에서 피내진단에 의한 양성우 살처분 및 보상금 지급 정책을 전개하면서 M. bovis의 사람전염은 급격히 감소하였다. 소 결핵은 우리나라에서 연간 0.15% 내외의 발생을 보이고 있으며, 발생의 주원인으로는 외부입식소, 인근발생농장, 과거발생농장의 사후관리소홀 등이다. 사람 결핵의 주원인균인 M. tuberculosis와 M. bovis는 유전체가 99.9% 유사하며, M. bovis를 M. tuberculosis의 아종으로 분류하기도 한다. 두 세균은 M. tuberculosis complex에 속하며, M. tuberculosis와 M. bovis이외에도 M. africanum, M. canettii, M. microti, M. pinnipedii 등이 있다. M. bovis는 M. tuberculosis complex중에서 가장 넓은 숙주범위를 가진다. M. bovis의 대표적인 숙주는 종이름에도 나타나 있듯이 소이다. 소결핵 전파원으로서는 M. bovis에 감염된 소가 가장 중요하다. 소 이외에도 면양, 산양, 말, 돼지, 사슴, 엘크, 영양 (antelope, kudus, elands, sitatungas, oryxes, addaxes), 개, 고양이, 흰족제비 (ferrets), 낙타, 여우, 밍크, 오소리, 쥐, 영장류, 라마, 맥 (tapirs), 코끼리, 코뿔소 (rhinoceroses), 주머니쥐, 땅다람쥐 (ground squirrels), 수달 (otters), 물개, 산토끼 (hares), 두더쥐 (moles), 너구리 (raccoons), 코요테, 사자, 호랑이, 표범, 살쾡이 (lynx) 등에 감염될 수 있으나, 대부분 종결숙주 (spillover host)로 가축의 결핵방제가 유지되고 있는 국가에서는 야생동물 결핵의 가축 전염이 문제시되고 있다. M. bovis는 주로 호흡기와 소화기를 통하여 감염되며, 결핵결절이 형성되는 부위를 관찰하면 감염경로를 추정할 수 있다. 결핵에 감염되면, 초기에는 뚜렷한 임상증상을 보이지 않으나, 아침, 추운 날씨, 또는 운동 중에 심한 기침을 하며, 호흡곤란을 일으킬 수 있다. 결핵은 감염되어도 대부분 무증상이기 때문에 피내진단, 결핵결절 병리소견, 원인균 분리 등에 의해 진단하여야 한다. 감염된 결핵균은 탐식세포에 탐식되어 특징적인 육아종성 결절 병변으로 진행된다. 현재 결핵은 피내진단과 결핵결절 병리소견 등에 의해 판정하고 있다. 최신 진단법으로는 피내진단을 대체할 수 있는 인터페론 감마 검사법과 우군의 결핵 스크리닝과 말기 결핵 검사에 우수한 항체진단법이 개발되어 있다. 그러나, 소 결핵 근절을 위해서는 일관성있는 진단법과 진단기준을 적용하는 것이 중요한 성공요인중 하나이다. 소결핵 청정국인 호주와 캐나다에서는 피내진단과 도축장 결절검사를 결핵 양성우 색출방법의 근간으로 삼고 있으며, 소결핵 근절의 최종단계에 이르러서는 특이적인 검사법을 적용하였지만, 근절목적상 민감성이 높은 피내진단법을 사용하였다. 이와 더불어, 피내진단 양성우의 부검소견과 원인균 분리를 통해 결핵을 확진하여 출처농장의 역추적 검사를 통하여 결핵 양성소를 제거하였다. 한편, 결핵의 농장간 및 지역간 전파방지를 위해 결핵 청정농장과 결핵 오염농장, 결핵 청정지역과 결핵 오염지역 구분을 통하여 결핵 오염농장과 결핵 오염지역으로부터 결핵 청정농장과 결핵 청정지역으로의 이동전 결핵 검진을 통해 개체 이동에 따른 결핵 전파를 근본적으로 차단하는 시스템을 엄격히 적용한 것이 주요한 성공 요인중 하나였다. 호주 결핵 근절정책 성공요인을 요약하면, 일관성 있는 결핵진단법 적용, 양성우 출처농장의 철저한 역추적 검사, 개체 이동전 결핵 음성증명 확인, 농가단체의 경제적 및 방역상 적극적인 지원 및 협조 결핵의 지속적인 모니터 링과 현장요구에 부응하는 방제신기술의 지속적인 연구개발 등을 들 수 있다. 최근 들어 국내 동물 결핵은 소, 특히, 한우의 결핵발생이 증가하고 있으며, 사슴 결핵발생도 증가하고 있다. 농장간 및 지역간에 결핵 감수성 가축, 특히, 소와 사슴의 거래가 아주 복잡하게 이루어지고 있는 현실을 고려할 때, 결핵전파의 주원인인 결핵감염 소나 사슴의 농장내 반입을 철저히 차단해야 할 것이다. 이때, 개체 검사는 물론이고, 출처농장에 대한 결핵 음성을 확인한 후 입식하여야 할 것이며, 입식 후에도 60일정도 격리사육하면서 피내진단등 결핵검진 후 음성인 경우에만 합사하여야 할 것이다. M. bovis는 사람을 비롯한 거의 모든 온혈동물에서 결핵을 일으킬 수 있기 때문에, 결핵 감염소로 판정된 농장 종사자는 각 시도 보건소의 협조를 받아 결핵검진을 받도록 해야 한다. 농장 가축에 접촉할 수 있는 야생동물의 접촉을 차단하여야 하며, 특히, 농장 사료의 야생동물에 의한 오염을 방지할 수 있는 사료창고관리를 철저히 해야 한다. 결핵 감염소를 다룰 때는 분비물 또는 가검물에 의해 감염될 수 있기 때문에 개인방역장비 - 방역복, 마스크, 비닐장갑, 비닐장화 - 를 착용한 상태에서 다루어야 한다. 특히, 결핵 감염소를 매몰 또는 소각하는 과정에서 결핵 감염소의 배설물 및 분비물 처리를 철저히 하여야 한다. 모든 작업을 마친 후에는 개인방역장비, 매몰 또는 소각에 사용하였던 장비 등을 청소 및 소독하고 필요시 소각 또는 매몰하여야 하며, 개인감염위험과 타인 감염위험을 방지하기 위해 노출부위를 세척하여야 한다.

• Journal of the Korean earth science society
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• v.34 no.4
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• pp.356-367
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• 2013

We study on the concept and reason of seasonal change that 164 university students have. Subsequently the concept types on the seasonal change are classified according to the characteristics and conceptual change after teaching on astronomy. All of the students were simply checked by the questionnaire of multiple choice and essay method before learning on the subjects. And then they answered to questionnaires of similar type after one semester. By the analyzed results, we classify it to three steps of hierarchical concept structure. The first step is the cosmic perspective that is related to the Earth's condition and motion. The second step is the influence of the Earth that is directly affected by the first step. The third step is observer's perspective on the Earth depending on the second step. Among the answers, the first step is prominent and second step is rare. The answers on the reason of seasonal change show some kinds of type which are 1st, 1-2nd, 1-3rd, and 1-2-3rd step. By the result, it is arranged in sequence like as 1-3rd>1st>1-2nd>1-2-3rd type. The lowest number of students was 2nd step of the Sun's altitude and duration of daytime in pre-test. However the students of 2nd step obtained more correct scientific concept on the seasonal change after learning on the subjects, and got the higher score in the post-test than in the pre-test. We found how much important the hierarchical structure on the reason of seasonal change is. As the results, second step on the learning of the Sun's altitude and duration of daytime essentially have to teach after first step. And then third step have to teach. At last, it is sure that the students can obtain the concept of seasonal change.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.241-247
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• 2012

Purpose: This study was conducted to assess the association of metabolic syndrome and its components with glaucoma. Methods: We investigated the associations of metabolic syndrome and its components (abdominal obesity, impaired fasting glucose, high blood pressure, and dyslipidemia) with glaucoma using data from 19,162 adults aged 40 or above among the Korean National Health and Nutrition Examination Survey III (2005), IV (2007-9), V (2010). The logistic regression analysis was used for assessing those associations after adjusting demographic, lifestyle, and social economic status and for assessing the association of metabolic medication intakes with glaucoma risks. Results: After adjusting for age and sex, the risk of glaucoma was significantly higher in the subjects with impaired fasting glucose(Odds Ratio (95% confidence interval): 1.78 (1.25, 2.53)) and metabolic syndrome (1.45 (1.01, 2.08)) than subjects without those. These associations increased when additional adjusting for smoking, alcohol use, regular physical activity, income, education status(impaired fasting glucose: 1.89 (1.29, 2.77), metabolic syndrome: 1.52 (1.03, 2.25)). Glaucoma prevalence was borderline significantly increased according to the number of metabolic abnormalities(age and sex adjusted p for trend = 0.055). Use of antihypertensive medication was significantly associated with the risk of glaucoma. Conclusions: Metabolic syndrome and impaired fasting glucose were significantly associated with the increased glaucoma risk. Use of antihypertensive medication was also significantly associated with the increased glaucoma risk.

• Parasites, Hosts and Diseases
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• v.26 no.3
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• pp.175-178
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• 1988

In an attempt to analyze the clonorchicidal activity of linoleic acid and ethyl linoleate in vitro, the wormicidal effects on Clonorchis sinensis were chronologically monitored in dose titration experiments. Encysted metacercariae were killed within a period of 31, $0{\pm}4.0$ min, 149.3k4. 1 min and $207.0{\pm}13.5$ min with 100.0 mg, 0.1 mg and 0.001 mg linoleic acid, respectively. The time required for the linoleic acid to kill adult worms was 167, $0{\pm}0.8$ min with 100.0mg, $253.0{\pm}0.8$ min with 0.1mg, and $277.0{\pm}0.8$ min at 0.001mg titration. Clonorchicidal activity of ethyl linoleate was relatively delayed as death was observed within $263.3{\pm}2.9$ min, $286.0{\pm}0.5$ min, and $318.0{\pm}0.8$ min for 100.0 mg/ml, 0.1 mg/ml and 0.001 mg/ml concentrations, respectively. The wormicidal effects observed with these pure anti-clonorchal substances were found to be similar to the biological activity of native products derived from the mucus of the fresh water fish.

• The Korean Journal of Mycology
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• v.13 no.3
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• pp.169-177
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• 1985

The studies were carried out to obtain the basic data for maximizing the protoplast yields from the mycelia of P. ostreatus and P. sajor-caju. Some factors affecting the regeneration of the protoplast of both species and the productivity of their reversion were also examined. The maximum yields of protoplasts were obtained from four days cultured mycelia of both species on cellophan membrane placed on the surface of PSA or MCM media in a petri dish. The optimal concentration of lytic enzyme Novozym 234 for protoplast releasing was 5 mg per ml of 0.5 M phosphate buffer solution with 0.6 M sucrose or 0.6 M $MgSO_4$ at pH 6.0. The greatest number of protoplasts was released 3 hours after incubation of the mycelia of P. ostreatus and after 4 hours for the P. sajor-caju in the lytic enzyme solution. Among the osmotic stabilizer solutions tested 0.6 M sucrose and 0.6 M KCl showed the best regeneration rates of the protoplasts of both species. When 0.75 % agar solution was over-layed on the regeneration media immediately after inoculation of the protoplast the regeneration rates were greatly enhanced. The ampicillin added to the agar solution prevented bacteria from infection. The reverted isolates produced the sporophores and basidial spores just like their parents without any mutations when they were cultivated in a broad mouth bottle with sawdust substrates.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.4
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• pp.235-249
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• 2002

This study was accompolished to analyze and compare the number and area of the occlusal contact points in healthy volunteers and athletes with normal occlusion. Before the study, 89 athletes(sports career:8.6 years, average age 20) at Kyung Hee University were selected, and survey was accomplished for athlete's recognition about sports dentistry. For this study, 15 athletes(13 amles and 2 females with average age 20) and 21 healthy volunteers(14 mles and 7 females with average age 20.09) at Kyung Hee University were selected. The visual display acquired by scanning of occlusal record in maximal intercuspation was converted into 16 gray value image. Then, using computer program(J & Lee Occlusal Analyser), the pixel which was in definite range of the gray value was recognized, and the numbers of recognized pixel were calculated to area. The results were as follows : (1) On the survey about sports dentistry, 28% of 89 athletes didn't agree that human occlusion may be important, and 30% didn't have any idea of the influence of human occlusion during their sports activities. (2) The average numbers of total occlusal contact points were 31.05 in control group, and 34.67 in athlete group. The average area of total occlusal contacts was $100.25mm^2$ in control group, and $127.78mm^2$ in athlete group. (3) In control group, the average numbers of occlusal contact points were revealed in order as follows; the first molar(8.48), the second molar(8.24), the second premolar(4.71), the lateral incisor(2.90), the first premor(2.43), the central incisor(2.19), and the canine(2.1). The least average in canine(2.1) was similar to the average(2.19) in central incisor and (2.09) in lateral incisor. In athlete group, the average numbers of occlusal contact points were revealed in order as follows; the first molar(8.87), the second molar(8.47), the second premolar(5.60), the canine(3.80), the lateral incisor(3.33), the first premolar(2.67), and the central incisor(1.93). (4) In control group, the average areas of occlusal contact surface were revealed in order as follows; the first molar($39.47mm^3$), the second molar($37.54mm^3$), the second premolar($9.54mm^3$) the first premolar($6.18mm^3$), canine($3.49mm^3$), the central incisor($2.76mm^3$), and the lateral incisor($1.28mm^3$). In athlete group, the average areas of occlusal contact surface were revealed in order as follows; the first molar($44.11mm^3$), the second molar($40.69mm^3$), the second premolar($16.50mm^3$), the first premolar($9.39mm^3$), the canine($5.08mm^3$), the lateral incisor($3.7mm^3$), and the central incisor($2.25mm^3$). (5). With aging in both control and athlete group, there was a decreasing tendancy in average number of occlusal contact point, and was an increasing tendancy in average area of occlusal contact surface. In comparison at each age, both the numbers and area of occlusal contact were greater in athlete group than in control group. It was not significant in the numbers of occlusal contact points beween athlete and control group(p>0.1), but significant in the area of occlusal contact surface(p<0.05). (6) In comparision as to the kind of sports(Gymnastics:2, Rugby:3, Soccor:5, Ice hocky:5), the numbers of occlusal contact points were the most in ice hocky, and the area of occlusal contact surface was the greatest in gymnastics. With increasing a career in athlete group, there was a decreasing tendancy in average numbers of occlusal contact points, and was an increasing tendancy in average area of occlusal contact surface.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.1
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• pp.7-12
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• 2014

Purpose:The effectiveness of transdermal buprenorphine patch on the patients with frozen state of frozen shoulder was evaluated. Materials and Methods: Between March and September in 2013, 127 patients with pain and limited range of motion in shoulder joint over 6 months were included. Every patient was confirmed the diagnosis through MRI or ultrasonogram and each patient received intra-articular injection of steroid once. After 2~4 weeks, every patient was interviewed via telephone survey and finally 105 patients were included, 54 patients received only oral NSAIDs (NP group) while 51 patients received additional transdermal buprenorphine patch (BP group). Pain and functional visual analog scale (PVAS, FVAS), American Shoulder Elbow Society (ASES) score was checked. Results: Generally, every outcome variables showed improvements in both groups (p<0.001). PVAS score after treatment showed superior result in NP group but it was not significant (p=0.088). In ASES score, NP group had superior result than BP group and it had significant difference. Similarly in FVAS, NP group showed superior result but the data before treatment was significantly different (p=0.028) Conclusion: Transdermal buprenorphine patch didn't show superior treatment result in the patient with frozen state of frozen shoulder which was applied with oral NSAIDs after single intra-articular glenohumeral steroid injection in short-term follow-up.