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Original Article The amounts and speed of polymerization shrinkage and microhardness in LED cured composites
Sung-Ho Park, Su-Sun Kim, Yong-Sik Cho, Soon-Young Lee, Do-Hyun Kim#, Yong-Joo Jang#, Hyun-Sung Mun#, Jung-Won Seo#, Byung-Duk Noh
2003;28(4):-359.
DOI: https://doi.org/10.5395/JKACD.2003.28.4.354
Published online: July 31, 2003

Department of Conservative Dentistry, Yonsei University, Korea.

#College of Dentistry, Yonsei University, Korea.

Corresponding author (sunghopark@yumc.yonsei.ac.kr)

Copyright © 2003 Korean Academy of Conservative Dentistry

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  • This study evaluated the effectiveness of the light emitting diode(LED) units for composite curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing unit, the microhardness of 2mm composite, Z250, which had been light cured by the LEDs (Ultralume LED2, FreeLight, Developing product D1) or QTH (XL 3000) were compared on the upper and lower surface. One way ANOVA with Tukey and Paired t-test was used at 95% levels of confidence. In addition, the amount of linear polymerization shrinkage was compared between composites which were light cured by QTH or LEDs using a custom-made linometer in 10s and 60s of light curing, and the amount of linear polymerization shrinkage was compared by one way ANOVA with Tukey.
    The amount of polymerization shrinkage at 10s was
    XL3000 > Ultralume 2, 40, 60> FreeLight, D1 (P<0.05)
    The amount of polymerization shrinkage at 60s was
    XL3000 > Ultralume 2, 60> Ultralume 2,40> FreeLight, D1 (P<0.05)
    The microhardness on the upper and lower surface was as follows;
    It was concluded that the LEDs produced lower polymerization shrinkage in 10s and 60s compared with QTH unit. In addition, the microhardness of samples which had been cured with LEDs was lower on the lower surfaces than the upper surfaces whereas there was no difference in QTH cured samples.
  • Keywords: LED; Microhardenss; Polymerization shrinkage; Composites; QTH
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Fig. 1
Schematic diagram of custome made linometer with sample in place.
jkacd-28-354-g001.jpg
Fig. 2
Change in the amount of linear polymerization shrinkage versus time in Z250 that was light cured with LEDs or QTH
jkacd-28-354-g002.jpg
Table 1
Curing light used in the present study
jkacd-28-354-i001.jpg
Table 2
Amount of linear polymerization shrinkage at 10s and 60s of light curing (um)
jkacd-28-354-i002.jpg
Table 3
Microhardnesses of upper & lower surfaces of samples

*indicates different microhardness between upper and lower surface in the paired- t test at 95% levels of confidence Different letters indicate different microhardness on the upper or lower surface at the 95% levels of confidence

jkacd-28-354-i003.jpg

Tables & Figures

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    Citations

    Citations to this article as recorded by  
    • The polymerization rate and the degree of conversion of composite resins by different light sources
      Joo-Hee Ryoo, In-Bog Lee, Hyun-Mee Yoo, Mi-Ja Kim, Chang-In Seok, Hyuk-Choon Kwon
      Journal of Korean Academy of Conservative Dentistry.2004; 29(4): 386.     CrossRef
    • Measurements of shrinkage stress and reduction of inter-cuspal distance in maxillary premolars resulting from polymerization of composites and compomers
      Soon-Young Lee, Sung-Ho Park
      Journal of Korean Academy of Conservative Dentistry.2004; 29(4): 346.     CrossRef

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      The amounts and speed of polymerization shrinkage and microhardness in LED cured composites
      J Korean Acad Conserv Dent. 2003;28(4):354-359.   Published online July 31, 2003
      DOI: https://doi.org/10.5395/JKACD.2003.28.4.354
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    The amounts and speed of polymerization shrinkage and microhardness in LED cured composites
    Image Image
    Fig. 1 Schematic diagram of custome made linometer with sample in place.
    Fig. 2 Change in the amount of linear polymerization shrinkage versus time in Z250 that was light cured with LEDs or QTH

    Fig. 1

    Fig. 2

    The amounts and speed of polymerization shrinkage and microhardness in LED cured composites

    Curing light used in the present study

    Amount of linear polymerization shrinkage at 10s and 60s of light curing (um)

    Microhardnesses of upper & lower surfaces of samples

    *indicates different microhardness between upper and lower surface in the paired- t test at 95% levels of confidence Different letters indicate different microhardness on the upper or lower surface at the 95% levels of confidence
    Table 1 Curing light used in the present study

    Table 2 Amount of linear polymerization shrinkage at 10s and 60s of light curing (um)

    Table 3 Microhardnesses of upper & lower surfaces of samples

    *indicates different microhardness between upper and lower surface in the paired- t test at 95% levels of confidence Different letters indicate different microhardness on the upper or lower surface at the 95% levels of confidence

    Table 1

    Table 2

    Table 3

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