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HOME > Restor Dent Endod > Volume 28(6); 2003 > Article
Original Article The effect of viscosity, specimen geometry and adhesion on the linear polymerization shrinkage measurement of light cured composites
In-Bog Lee, Ho-Hyun Son, Hyuk-Chun Kwon, Chung-Moon Um, Byeong-Hoon Cho
2003;28(6):-466.
DOI: https://doi.org/10.5395/JKACD.2003.28.6.457
Published online: November 30, 2003

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Corresponding author (chobh@plaza.snu.ac.kr)

Copyright © 2003 Korean Academy of Conservative Dentistry

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  • Objectives
    The aim of study was to investigate the effect of flow, specimen geometry and adhesion on the measurement of linear polymerization shrinkage of light cured composite resins using linear shrinkage measuring device.
  • Methods
    Four commercially available composites - an anterior posterior hybrid composite Z100, a posterior packable composite P60 and two flowable composites, Filtek flow and Tetric flow - were studied. The linear polymerization shrinkage of composites was determined using 'bonded disc method' and 'non-bonded' free shrinkage method at varying C-factor in the range of 1~8 by changing specimen geometry. These measured linear shrinkage values were compared with free volumetric shrinkage values.
    The viscosity and flow of composites were determined and compared by measuring the dropping speed of metal rod under constant load.
  • Results
    In non-bonded method, the linear shrinkage approximated one third of true volumetric shrinkage by isotropic contraction. However, in bonded disc method, as the bonded surface increased the linear shrinkage increased up to volumetric shrinkage value by anisotropic contraction. The linear shrinkage value increased with increasing C-factor and approximated true volumetric shrinkage and reached plateau at about C-factor 5~6. The more flow the composite was, reduced linear shrinkage was measured by compensation radial flow.
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  • 2. Sakaguchi RL, Sasik CT, Bunczak MA, Douglas WH. Strain gauge method for measuring polymerization contraction of composite restoratives. J Dent. 1991;19: 312-316.ArticlePubMed
  • 3. Penn RW. A recording dilatometer for measuring polymerization shrinkage. Dent Mater. 1986;2: 78-79.ArticlePubMed
  • 4. Rees JS, Jacobsen PH. The polymerization shrinkage of composite resins. Dent Mater. 1989;5: 41-44.ArticlePubMed
  • 5. Sakaguchi RL, Berghe HX. Reduced light energy density decreases post gel contraction while maintaining degree of conversion in composites. J Dent. 1998;26: 695-700.ArticlePubMed
  • 6. Suh BI, Feng L, Wang Y, Cripe C, Cincione F, de Rjik W. The effect of the pulse delay cure technique on residual strain in composites. Compend Contin Educ Dent. 1999;20: 2 Suppl. 4-14.
  • 7. Silikas N, Eliades G, Watts DC. Light intensity effects on resin composite degree of conversion, shrinkage strain. Dent Mater. 2000;16: 292-296.PubMed
  • 8. Cook WD, Forrest M, Goodwin AA. A simple method for the measurement of polymerization shrinkage in dental composites. Dent Mater. 1999;15: 447-449.ArticlePubMed
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Fig. 1-a
The structure of instrument to measure linear shrinkage.
jkacd-28-457-g001.jpg
Fig. 1-b
The geometry of composite specimen sandwiched between two glass plates. Polymerization shrinkage creates axial (vertical) and radial (horizontal) contraction of the specimen.
jkacd-28-457-g002.jpg
Fig. 2
Linear polymerization shrinkage curves of composites as a function of time at C-factor ≈ 6.
jkacd-28-457-g003.jpg
Fig. 3
Linear polymerization shrinkage of composites measured using bonded disc method. The linear shrinkage value increased with increasing C-factor and approximated volumetric shrinkage and reached plateau at about C-factor 5~6.
a) Linear shrinkage of Z1 as a function of C-factor.
b) Linear shrinkage of P6 as a function of C-factor.
c) Liner shrinkage of FF as a function of C-factor.
d) Linear shrinkage of TF as a function of C-factor.
jkacd-28-457-g004.jpg
Fig. 4
Linear polymerization shrinkage of composites measured using non-bonded disc method with Vaseline. The linear shrinkage is not affected by specimen diameter and is approximated the theoretical linear shrinkage value calculated from true volumetric shrinkage value.
a) Linear shrinkage of Z1 as a function of specimen geometry.
b) Linear shrinkage of P6 as a function of specimen geometry.
c) Liner shrinkage of FF as a function of specimen geometry.
d) Linear shrinkage of TF as a function of specimen geometry.
jkacd-28-457-g005.jpg
Fig. 5
Peak time (peak shrinkage rate time) of Z1 as a function of C-factor.
jkacd-28-457-g006.jpg
Fig. 6
Relative viscosity of composites based on flow normalized to Z1.
jkacd-28-457-g007.jpg
Table 1
Materials used in this study
jkacd-28-457-i001.jpg
Table 2
Volumetric polymerization shrinkage and linear shrinkage of composite resins at varying C-factor

S.D. in parenthesis

N=5 in volumetric shrinkage measurement, however the number of samples varied in linear shrinkage measurement.

jkacd-28-457-i002.jpg
Table 3
Cure speed based on Peak Time (P.T.) of composites at varying C-factor
jkacd-28-457-i003.jpg
Table 4
Consistency (viscosity) based on the flow of composite resins

Relative flow is the flow value normalized to that of Z1 S.D. in parenthesis.

N=5

jkacd-28-457-i004.jpg

Tables & Figures

REFERENCES

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    • Influence of cavity size and restoration methods on the cusp deflection in composite restoration
      Mi-Ra Lee, In-Bog Lee, Chang-In Seok, Sang-Tag Lee, Chung-Moon Um
      Journal of Korean Academy of Conservative Dentistry.2004; 29(6): 532.     CrossRef

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      The effect of viscosity, specimen geometry and adhesion on the linear polymerization shrinkage measurement of light cured composites
      J Korean Acad Conserv Dent. 2003;28(6):457-466.   Published online November 30, 2003
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    The effect of viscosity, specimen geometry and adhesion on the linear polymerization shrinkage measurement of light cured composites
    Image Image Image Image Image Image Image
    Fig. 1-a The structure of instrument to measure linear shrinkage.
    Fig. 1-b The geometry of composite specimen sandwiched between two glass plates. Polymerization shrinkage creates axial (vertical) and radial (horizontal) contraction of the specimen.
    Fig. 2 Linear polymerization shrinkage curves of composites as a function of time at C-factor ≈ 6.
    Fig. 3 Linear polymerization shrinkage of composites measured using bonded disc method. The linear shrinkage value increased with increasing C-factor and approximated volumetric shrinkage and reached plateau at about C-factor 5~6. a) Linear shrinkage of Z1 as a function of C-factor. b) Linear shrinkage of P6 as a function of C-factor. c) Liner shrinkage of FF as a function of C-factor. d) Linear shrinkage of TF as a function of C-factor.
    Fig. 4 Linear polymerization shrinkage of composites measured using non-bonded disc method with Vaseline. The linear shrinkage is not affected by specimen diameter and is approximated the theoretical linear shrinkage value calculated from true volumetric shrinkage value. a) Linear shrinkage of Z1 as a function of specimen geometry. b) Linear shrinkage of P6 as a function of specimen geometry. c) Liner shrinkage of FF as a function of specimen geometry. d) Linear shrinkage of TF as a function of specimen geometry.
    Fig. 5 Peak time (peak shrinkage rate time) of Z1 as a function of C-factor.
    Fig. 6 Relative viscosity of composites based on flow normalized to Z1.
    The effect of viscosity, specimen geometry and adhesion on the linear polymerization shrinkage measurement of light cured composites

    Materials used in this study

    Volumetric polymerization shrinkage and linear shrinkage of composite resins at varying C-factor

    S.D. in parenthesis

    N=5 in volumetric shrinkage measurement, however the number of samples varied in linear shrinkage measurement.

    Cure speed based on Peak Time (P.T.) of composites at varying C-factor

    Consistency (viscosity) based on the flow of composite resins

    Relative flow is the flow value normalized to that of Z1 S.D. in parenthesis.

    N=5

    Table 1 Materials used in this study

    Table 2 Volumetric polymerization shrinkage and linear shrinkage of composite resins at varying C-factor

    S.D. in parenthesis

    N=5 in volumetric shrinkage measurement, however the number of samples varied in linear shrinkage measurement.

    Table 3 Cure speed based on Peak Time (P.T.) of composites at varying C-factor

    Table 4 Consistency (viscosity) based on the flow of composite resins

    Relative flow is the flow value normalized to that of Z1 S.D. in parenthesis.

    N=5


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