Marginal gap formation of light-activated restorative materials: Effects of immediate setting shrinkage and bond strength

M. Irie, K. Suzuki, D. C. Watts

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Objectives: The purpose of this study was to explore multiple correlations between shrinkage, bonding and marginal gap parameters, immediately after light-activation, for three classes of restorative materials. The correlations of interest were between: (a) their marginal gap formation in tooth cavities, (b) their free setting shrinkage-strain determined by two different measurement methods ((i) the marginal gap-width in a non-bonding Teflon cavity and (ii) a linear (diametral) measure of shrinkage-strain), and (c) their shear bond strengths to enamel and to dentin. Methods: The maximum marginal gap width and the opposing width (if any) in the tooth cavity were measured immediately (3min) after light-activation. Two factors for the setting shrinkage-strain and the shear bond strength to enamel and to dentin were measured concomitantly. Results: Out of the set of restorative materials investigated, those that produced a smaller marginal gap in the tooth cavity had a smaller marginal gap in the Teflon cavity. There was a highly significant correlation between the two parameters (r=0.914, p0.05). Thus the restorative materials that produced a smaller marginal gap in the tooth cavity did not generally have a smaller diametral setting shrinkage-strain. Furthermore, no relationship was observed between the marginal gap in the tooth cavity and the shear bond strength to enamel or to dentin (p>0.50). Significance: For light-activated restorative materials during the early stage of setting (

Original languageEnglish
Pages (from-to)203-210
Number of pages8
JournalDental Materials
Issue number3
Publication statusPublished - May 2002



  • Bond strength
  • Compomer
  • Light curing
  • Marginal gap formation
  • Resin composite
  • Resin-modified glass-ionomer cement
  • Setting shrinkage

ASJC Scopus subject areas

  • Dentistry(all)

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