• Title/Summary/Keyword: lever

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Effect of prosthetic designs and alveolar bone conditions on stress distribution in fixed partial dentures with pier abutments (중간 지대치가 존재하는 고정성 국소의치에서 보철물 설계 및 치조골 상태가 응력분포에 미치는 영향)

  • Cho, Wook;Kim, Chang-Seop;Jeon, Young-Chan;Jeong, Chang-Mo
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.3
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    • pp.328-334
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    • 2009
  • Statement of problem: Pier abutments act as a Class I fulcrum lever system when the teeth are incorporated in a fixed partial denture with rigid connectors. Therefore non-rigid connector incorporated into the fixed partial denture might reduce the stresses created by the leverage. Purpose: The purpose of this study was to evaluate, by means of finite element method, the effects of non-rigid connectors and supporting alveolar bone level on stress distribution for fixed partial dentures with pier abutments. Material and methods: A 2-dimensional finite element model simulating a 5-unit metal ceramic fixed partial denture with a pier abutment with rigid or non-rigid designs, the connector was located at the distal region of the second premolar, was developed. In the model, the lower canine, second premolar, and second molar served as abutments. Four types of alveolar bone condition were employed. One was normal bone condition and others were supporting bone reduced 20% height at one abutment. Two different loading conditions, each 150 N on 1st premolar and 1st molar and 300N on 1st molar, were used. Results: Two types of FPD were displaced apically. The amount of displacement decreased in an almost linear slope away from the loaded point. Non-rigid design tended to cause the higher stresses in supporting bone of premolar and molar abutments and the lower stresses in that of canine than rigid design. Alveolar bone loss increased the stresses in supporting bone of corresponding abutment. Conclusion: Careful evaluation of the retentive capacity of retainers and the periodontal condition of abutments may be required for the prosthetic design of fixed partial denture with a pier abutment.

The Study of the Diet Style and Relationships among Vitamin and Nutrient Supplement Intakes, Serum Lipid Levels, Blood Sugar and Blood Pressure of Adult Female (채식 성인여성의 식사형태 및 비타민, 영양제 복용과 혈중 지질, 혈당, 혈압과의 관련성에 관한 비교연구)

  • 차복경;최원경
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.2
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    • pp.306-314
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    • 2002
  • The purpose of this study is to examine the relation between vegetarian diet and the risk factors of cardiovascular disease. The subjects of the study were 127 Buddhist nuns (age: 23 ~79 yr) for vegetarians and 235 healthy female adults (age: 23 ~79 yr) for non-vegetarians. This study covers food consumption survey, anthropometric measurement, amount of energy expenditure, physical activity and clinical examination. Average body mass index (BMI) of vegetarians and non-vegetarians were 22.47 and 21.08, waist/hip ratio (WHR) was 0.85 and 0.84, percentage of body fat (%BF) was 28.79 and 26.55, respectively. Average duration of vegetarian diet of the vegetarians was 13.16 years. The triglyceride levee of the vegetarians was significantly lower for those who take nutrient tablet compared to those who either take vitamins or who do not take any nutrient supplement. Taking vitamins or nutrient tablet did not give any significant difference in total-cholesterol and LDL-cholesterol for vegetarians, while significantly high triglyceride was observed for the non-vegetarians taking nutrient tablet than the ether non-vegetarians. Taking vitamins or nutrient tablet did not affect the lever of HDL-cholesterol for either vegetarians or non-vegetarians. Athrogenic index (AI) was lower for the vegetarian group tailing nutrient tablet and for the non-vegetarian group not taking vitamins and nutrient tablet, than the other respective groups. Blood sugar of the vegetarians who take nutrient tablet was significantly lower than those tailing vitamins, while blood sugar of the non-vegetarians not taking any nutrient supplement was significantly lower than those taking nutrient tablet.

Settlement Instrumentation of Greenhouse Foundation in Reclaimed Land (간척지 온실 기초의 침하량 검토)

  • Choi, Man Kwon;Yun, Sung Wook;Yu, In Ho;Lee, Jong-Won;Lee, Si Young;Yoon, Yong Cheol
    • Journal of Bio-Environment Control
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    • v.24 no.2
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    • pp.85-92
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    • 2015
  • This study examined the settlement of a 1-2W type greenhouse using a timber pile, which was recently established on Gyehwa-do reclaimed land, in order to obtain base data for the construction of a greenhouse on reclaimed land. The results of this study are as follows. foundation and timber pile increased over time, irrespective of the interior and exterior of the upon investigation of the ground, it was confirmed that there was no soft rock stratum (bedrock), and that a sedimentary stratum existed under the fill deposit, which is estimated to have been reclaimed during the site renovation. It was also found that a weathered zone was located under the fill deposit and sedimentary stratum, and that the soil texture of the entire ground floor consisted of clay mixed with sand, silty clay, and granite gneiss, in that order, regardless of boreholes. In addition, the underground water level was 0.3m below ground, regardless of boreholes. Despite a slight difference, the settlement of the greenhouse or measurement sites (channels). With regard to the pillar inside the greenhouse, except in the case of CH-2, the data at a site located on the side wall of the greenhouse (wind barrier side) indicated vibrations of relatively larger amplitude. Moreover, the settlement showed a significant increase during a certain period, which was subsequently somewhat reversed. Based on these phenomena, it was verified that the settlement range of each site in the interior and exterior of the greenhouse was between 1.0 and 7.5mm at this time, except in the case of CH-1. The results of the regression analysis indicated good correlation, with the coefficient of determination by site ranging between 0.6362 and 0.9340. Furthermore, the coefficient of determination ranged between 0.6046 and 0.8822 on the exterior of the greenhouse, which is lower than inside the greenhouse, but still indicates significant correlation.