| Initial dynamic viscoelasticity change of composites during light curing. | |
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MedLine Citation:
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PMID: 20170947 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVES: The aim of this study was to measure the initial dynamic viscoelastic modulus change of dental composites during light curing using a custom made oscillation rheometer. METHODS: Six commercial universal hybrid resin composites: Z100 (Z1), Z250 (Z2), Z350 (Z3), DenFil (DF), Tetric Ceram (TC), and Clearfil AP-X (CF) were examined. A custom designed oscillation rheometer was made, which consisted of three parts: (1) an oscillatory shear strain induction unit, (2) a measuring unit of parallel plates made of glass rods, and (3) a stress measurement unit. For the measurement of the initial viscoelastic modulus change of composites during light curing as a function of time, a dynamic oscillatory shear test was undertaken at a frequency of 6Hz and strain amplitude of 0.00579rad for 10s. From the strain-stress curves, the complex shear modulus (G*), storage shear modulus (G'), loss shear modulus (G'') and loss tangent (tandelta), and the time to reach a G* of 10MPa were determined. The data were analyzed with one-way ANOVA and Tukey's post hoc test (alpha=0.05). RESULTS: There were great differences in the development of viscoelasticity among materials. At 10s, the complex modulus G* of Z1 was the highest (563.7MPa), followed by CF, Z2, Z3, TC, and finally DF being the lowest (150.3MPa). The time to reach the G* of 10MPa ranged from 2.55s (Z1) to 4.06s (DF). The tandelta of the composites decreased with time as the polymerization reaction proceeded. SIGNIFICANCE: The initial modulus development of composites during curing plays a very important role in determining the polymerization shrinkage stress. The custom made oscillation rheometer was able to measure the very initial dynamic viscoelasticity change of several commercial composites during light curing; therefore, the instrument can be used to study the initial curing kinetics of newly developed composites. |
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Authors:
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Min-Ho Kim; Sun-Hong Min; Jack Ferracane; In-bog Lee |
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Publication Detail:
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Type: Journal Article Date: 2010-02-18 |
Journal Detail:
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Title: Dental materials : official publication of the Academy of Dental Materials Volume: 26 ISSN: 1879-0097 ISO Abbreviation: Dent Mater Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-03-24 Completed Date: 2010-06-15 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8508040 Medline TA: Dent Mater Country: England |
Other Details:
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Languages: eng Pagination: 463-70 Citation Subset: D |
Copyright Information:
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2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. |
Affiliation:
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Department of Conservative Dentistry and Dental Research Institute, Seoul National University, Yeongeon-Dong, Jongro-Gu, South Korea. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Analysis of Variance Composite Resins / chemistry*, radiation effects* Dental Bonding, Light-Cured* Dental Stress Analysis Elasticity Materials Testing Oscillometry Rheology / instrumentation Shear Strength Statistics, Nonparametric Viscosity |
| Chemical | |
Reg. No./Substance:
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0/Composite Resins |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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