Indirect restoration thickness and time after light-activation effects on degree of conversion of resin cement

Ana Paula Almeida Ayres, Carolina Bosso Andre, Rafael Rocha Pacheco, Adriana Oliveira Carvalho, Renata Cantanhede Bacelar-Sá, Frederick Allen Rueggeberg, Marcelo Giannini

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This study evaluated the effects of indirect restorative materials, curing conditions and time on the degree of conversion (DC) of a dual-cured resin cement using infrared spectroscopy. The resin cement (RelyX Unicem 2, 3M ESPE) was applied to the diamond surface of a horizontal attenuated-total-reflectance unit and activated using one of following conditions: self-cure, direct light exposure, light exposure through indirect restorative materials (resin nano-ceramic: Lava Ultimate, 3M ESPE or feldspathic ceramic: Vita Blocks Mark II, Vita Zahnfabrik). Four thicknesses (0.5, 1.0, 1.5 or 2.0 mm) of each indirect material were analyzed, and the light-activation was performed using a blue LED light. Data (n=5) were analyzed by three-way ANOVA, Tukey’s post hoc and Dunnett’s tests (α=5%). No significant differences in DC were observed between indirect materials of similar thickness. All groups exhibited higher DC after 10 min than after 5 min. At both times points, the self-cure group exhibited significantly lower DC than all the light exposure groups. Only when the overlying indirect restoration had a thickness of 2 mm did DC decrease significantly. The presence of a thick, indirect restoration can decrease the DC of resin cement. DC after 10 min was higher than after 5 min. The self-cure mode yielded lower DC than the light-activating one.

Original languageEnglish (US)
Pages (from-to)363-367
Number of pages5
JournalBrazilian dental journal
Issue number4
StatePublished - Aug 1 2015


  • Ceramic
  • Composite
  • Degree of conversion
  • Light-activation
  • Resin cement

ASJC Scopus subject areas

  • General Dentistry


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