• Title/Summary/Keyword: 재경화

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EFFECT OF CARBON DIOXIDE LASER ON INHIBITION OF DEMINERALIZATION AND REHARDENING OF PRIMARY TEETH (이산화탄소 레이저의 유치 탈회억제 및 재경화 효과)

  • Lee, Kwang-Hee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.30 no.2
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    • pp.320-325
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    • 2003

  • The purpose of study was to investigate the effect of carbon dioxide laser on demineralization inhibition and rehardening of primary tooth enamel according to its power and irradiation time. 2mm diameter circle on the primary enamel surface was irradiated by defocused $10.6{\mu}m$ superpulse carbon dioxide laser at 6 Watt 2 seconds or at 3 Watt 8 seconds, before or after demineralization by Coca-Cola for 24 hours. Enamel surface change was measured by the Diagnodent. The results were analyzed with the former study results of 3 Watt 4 seconds and 6 Watt and 4 seconds. Diagnodent scores increased significantly after demineralization of irradiated enamel at 6W 2s or 3W 8s (P<0.05). Among the four groups, only 6W 4s group showed obvious demineralization inhibition effect. Diagnodent scores reduced significantly after 6W 2s or 3W 8s irradiation of demineralized enamel(P<0.05). Among the four groups, 6W 4s showed nearly complete rehardening effect, and the other groups showed partial effect. Tooth discoloration only occurred at 6W 4s. It seemed that caries inhibition and tooth discoloration depend on laser power more than total irradiation energy.

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Effect of $CO_2$ Laser on Caries Inhibition Evaluated by Laser Fluorescence Measurement (이산화탄소 레이저의 우식 억제 효과에 대한 레이저형광측정 평가)

  • Kim, Seong-Hyeong;Lee, Kwang-Hee;Kim, Dae-Eop;Lee, Ji-Young;Song, In-Kyung
    • Journal of the korean academy of Pediatric Dentistry
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    • v.30 no.1
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    • pp.153-160
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    • 2003

  • The purpose of study was to evaluate the effects of the $CO_2$ laser irradiation on demineralization inhibition and rehardening of human primary tooth enamel by laser fluoresecence measurement. Enamel specimens were made from the human primary teeth. The center spots of the specimens about 2 mm diameter were irradiated by $CO_2$ laser at the conditions of focused continuous or defocused pulsed, 3 or 6 W, for 4 seconds, before or after the demineralization by Coca-Cola for 24 hours at $37^{\circ}C$. The Diagnodent was used to measure the degree of demineralization and rehardening. There was no significant difference between focused continuous and defocused pulsed irradiation. 6W irradiation inhibited the demineralization but 3W did not. 6W irradiation rehardened the demineralized enamel but 3W did partially. The color of enamel was changed to brown to black after 6W irradiation but 3W caused no color change. $CO_2$ laser irradiation showed the effects on demineralization inhibition and rehardening of human priamary tooth enamel, and the laser fluoresecence measurement technique seemed to be a valid evaluation method.

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대규모 벼농사 기계화 작업체계 및 기술 -미국, 러시아, 한국의 예를 중심으로-

  • 박우풍
    • Journal of Biosystems Engineering
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    • v.22 no.1
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    • pp.81-88
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    • 1997

  • 우리나라 벼농사 농작업의 대형기계화 추세에 따라 논 배미의 크기가 소규모에서 1 ㏊이상 대구획으로 재경지정리가 시작되고 있으며 3 ㏊이상의 벼농사 경영규모를 가진 농업인이 점점 증가하고 있는 경향이다. 그러나 우리나라에서는 아직까지 대규모 벼농사 기계화 작업체계와 기술이 확립되어 있지 않은 실정이다.(중략)

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