• Title/Summary/Keyword: Amalgam

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A STUDY ON THE STATE OF TREATMENT IN PEDODONTICS (소아치과(小兒齒科) 치료현황(治療現況)에 관(關)한 연구(硏究))

  • Cha, Moon-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.7 no.1
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    • pp.7-11
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    • 1980
  • 6877 children who visited to pedodontic department from 1976 to 1979, were surveyed on the state of dental caries, therapic inclination a year and yearly tendency of treatment. The results were as follows ; 1. The prevalence of dental caries tended to show the increase in general year by year. 2. Girls had higher d.e.f. T. & S. index and D.M.F. T. & S. index than boys generally. 3. Distribution of therapy a year. (1979) Amalgam Filling 4464 Pulpotomy 952 S.P.-Crown 1538 Gold Inlay 250 Space Maintainer 341 Extraction 1313 Orthodontic Appliance 206 4. Tendency of treatment in 1979 (compared with 1976) No. of new patients 87.5% increased Amalgam Filling 50.0% increased Extraction 31.4% increased Orthodontic Appliance 267.9% increased S.P.-Crown 225.8% increased Gold Inlay 27.8% decreased Space Maintainer 2.3% decreased Pulpotomy 20.5% decreased.

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Dependence of Round Type Electrodeless Lamp according to Ferrite Core and Cold Spot Temperature (둥근형 무전극 램프의 페라이트 코어와 냉점의 온도 의존성)

  • Jang, Hyeok-Jin;Yang, Jong-Kyung;Kim, Nam-Goon;Jung, Young-Il;Park, Dae-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.12
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    • pp.1078-1083
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    • 2009
  • Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of elecrodeless lamp are related to ferrite core and cold spot temperature.

ON THE DIMENSION OF AMALGAMATED ORDERED SETS

  • Lee, Jeh-Gwon
    • Bulletin of the Korean Mathematical Society
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    • v.29 no.1
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    • pp.117-123
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    • 1992
  • The dimension problem has been one of central themes in the theory of ordered sets. In this paper we focus on amalgamated ordered sets. Although some results can be obviously applied to infinite cases, we assume throughout that all ordered set are finite. If A and B are ordered sets whose orders agree on A.cap.B, then the amalgam of A and B is defined to the the set A.cup.B in which the order is the transitive closure of the union of the two orders, i.e., the smallest order containing the two orders, and is denoted by A .or. B .leq. dim A + dim B for any ordered sets A and B. But it is quite surprising that the dimension of the amalgam of certain 2-dimensional ordered sets can be arbitrarily large.

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아말감 충전후 증발수은의 치아주의조직내침수에 관한 연구

  • Kim, Soo-Chul
    • The Journal of the Korean dental association
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    • v.12 no.6
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    • pp.373-375
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    • 1974
  • This is to determine the possibility of penetration of evaporated mercury to periodontal tissue after amalgam filling. Class 5 cavities on upper canine, total 40 teeth from 10 dogs, were prepared and amalgam alloy which contain about 10 Ci of radioactive mercury were inserted. The animals were sacrificed after the experiment. The teeth were routinely decalcified, sectioned, autoradiographed by means of emulsion and stained by H & E. 1. Blackened grains were found along collagen fiber space underneath gingival sulcus floor. 2. Mercury particle deposited more at cervical portion of periodontium than apical portion. 3. Blackened grains were found along the Sharpey's fiber. Crest bone side was more evident than cement side. 4. Mercury penetration to periodontium of non-experimented tooth showed almost same findings as experimented one.

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SURFACE DEGRADATION OF GALLIUM-ALLOYS DURING TOOTH BRUSHING IN VITRO

  • Lee, Seok-Hyung
    • Journal of Dental Rehabilitation and Applied Science
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    • v.19 no.4
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    • pp.309-315
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    • 2003
  • When the exposure surface of restoration is brushed with various toothpaste in the mouth, wear or undesirable surface deposit of restoration can occur. Surface change of gallium alloys according to brushing and toothpaste may directly affect oral hygiene. The aim of this study was to evaluate the surface alterations of Gallium alloys during tooth brushing with different prophylactic agents. Two gallium-alloys and an amalgam as a control were investigated. Without and with brushing were applied with three kinds of prophylactic agents on the sample for 0, 1, 5, 10, 60 and 360 minutes. At each time interval, surface roughness was recorded by a profilometer and some pictures were taken by a SEM. All results were analyzed by the one-way ANOVA, followed by Tukey multiple comparisons and the simple linear regression analysis. The results indicate that gallium alloys are more susceptible to surface degradation during tooth brushing than amalgam with respect to the specific prophylactic agent used.