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2 "Rheology"
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Original Articles
Slumping resistance and viscoelasticity of resin composite pastes
Hee Yeon Suh, In Bog Lee
J Korean Acad Conserv Dent 2008;33(3):235-245.   Published online May 31, 2008
DOI: https://doi.org/10.5395/JKACD.2008.33.3.235
AbstractAbstract PDFPubReaderePub

The aim of this study was to develop a method for measuring the slumping resistance of resin composites and to relate it to the rheological characteristics.

Five commercial hybrid composites (Z100, Z250, DenFil, Tetric Ceram, ClearFil) and a nanofill composite (Z350) were used to make disc-shaped specimens of 2 mm thickness. An aluminum mold with square shaped cutting surface was pressed onto the composite discs to make standardized imprints. The imprints were light-cured either immediately (non-slumped) or after waiting for 3 minutes at 25℃ (slumped). White stone replicas were made and then scanned for topography using a laser 3-D profilometer. Slumping resistance index (SRI) was defined as the ratio of the groove depth of the slumped specimen to that of the non-slumped specimen. The pre-cure viscoelasticity of each composite was evaluated by an oscillatory shear test and normal stress was measured by a squeeze test using a rheometer. Flow test was also performed using a flow tester. Correlation analysis was performed to investigate the relationship between the viscoelastic properties and the SRI.

SRI varied between the six materials (Z100 < DenFil < Z250 < ClearFil < Tetric Ceram < Z350). The SRI was strongly correlated with the viscous (loss) shear modulus G' but not with the loss tangent. Also, slumping resistance was more closely related to the resistance to shear flow than to the normal stress.

Slumping tendency could be quantified using the imprint method and SRI. The index may be applicable to evaluate the clinical handling characteristics of composites.

Citations

Citations to this article as recorded by  
  • The change of the initial dynamic visco-elastic modulus of composite resins during light polymerization
    Min-Ho Kim, In-Bog Lee
    Journal of Korean Academy of Conservative Dentistry.2009; 34(5): 450.     CrossRef
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RHEOLOGICAL PROPERTIES OF RESIN COMPOSITES ACCORDING TO THE CHANGE OF MONOMER AND FILLER COMPOSITIONS
In-Bog Lee, Jong-Hyuck Lee, Byung-Hoon Cho, Sang-Tag Lee, Chung-Moon Um
J Korean Acad Conserv Dent 2004;29(6):520-531.   Published online January 14, 2004
DOI: https://doi.org/10.5395/JKACD.2004.29.6.520
AbstractAbstract PDFPubReaderePub
ABSTRACT Objectives.

The aim of this study was to investigate the effect of monomer and filler compositions on the rheological properties related to the handling characteristics of resin composites.

 Methods.

Resin matrices that Bis-GMA as base monomer was blended with TEGDMA as diluent at various ratio were mixed with the Barium glass (0.7 um and 1.0 um), 0.04 um fumed silica and 0.5 um round silica. All used fillers were silane treated. In order to vary the viscosity of experimental composites, the type and content of incorporated fillers were changed.

Using a rheometer, a steady shear test and a dynamic oscillatory shear test were used to evaluate the viscosity (η) of resin matrix, and the storage shear modulus (G′), the loss shear modulus (G″), the loss tangent (tanδ) and the complex viscosity (η *) of the composites as a function of frequency ω = 0.1-100 rad/s. To investigate the effect of temperature on the viscosity of composites, a temperature sweep test was also undertaken.

 Results.

Resin matrices were Newtonian fluid regardless of diluent concentration and all experimental composites exhibited pseudoplastic behavior with increasing shear rate. The viscosity of composites was exponentially increased with increasing filler volume%. In the same filler volume, the smaller the fillers were used, the higher the viscosities were. The effect of filler size on the viscosity was increased with increasing filler content. Increasing filler content reduced tanδby increasing the G′further than the G″ . The viscosity of composites was decreased exponentially with increasing temperature.

Citations

Citations to this article as recorded by  
  • The 3D Printing Behavior of Photocurable Ceramic/Polymer Composite Slurries Prepared with Different Particle Sizes
    Kukhyeon Ryu, Jinho Kim, Junghoon Choi, Ungsoo Kim
    Nanomaterials.2022; 12(15): 2631.     CrossRef
  • Surface roughness of experimental composite resins using confocal laser scanning microscope
    JH Bae, MA Lee, BH Cho
    Journal of Korean Academy of Conservative Dentistry.2008; 33(1): 1.     CrossRef
  • Effect of a new resin monomer on the microleakage of composite resin restorations
    JH Bae, YK Kim, PY Yoon, MA Lee, BH Cho
    Journal of Korean Academy of Conservative Dentistry.2007; 32(5): 469.     CrossRef
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  • 3 Crossref
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