Effect of light-curing time on light-cure/post-cure volumetric polymerization shrinkage and regional ultimate tensile strength at different depths of bulk-fill resin composites

Kurumi Ide, Masatoshi Nakajima, Juri Hayashi, Keiichi Hosaka, Masaomi Ikeda, Yasushi Shimada, Richard M. Foxton, Yasunori Sumi, Junji Tagami

Research output: Contribution to journalArticle

Abstract

The aim of this study was to investigate volumetric polymerization shrinkage (VS), using swept-source optical coherence tomography (SS-OCT), of bulk-fill composites with different light-curing strategies; immediately after light-irradiation and after 24 h, and to evaluate their regional ultimate tensile strength (UTS) at different curing depths. The immediate VS after photo-polymerization decreased when the curing light-curing time was reduced from 20 to 10 to 5 s. On the other hand, their VS values after 24 h significantly increased due to the post-cure polymerization, resulting in similar VS values at all the light-curing times. Five seconds light-curing decreased the regional UTS of resin composites after the 24 h period compared with the 10 and 20 s light-curing regimes; therefore, the remarkable progress of post-cure polymerization after light-curing for a short time would not lead to an improvement in the mechanical properties of resin composites. The influence of the light-curing time on the curing depth was dependent upon the bulk-fill composite material.

Original languageEnglish
Pages (from-to)621-629
Number of pages9
JournalDental materials journal
Volume38
Issue number4
DOIs
Publication statusPublished - 2019

Keywords

  • Bulk fill
  • Depth of cure
  • Optical coherence tomography
  • Ultimate tensile strength
  • Volumetric shrinkage

ASJC Scopus subject areas

  • Ceramics and Composites
  • Dentistry(all)

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