Alternative photoinitiator system reduces the rate of stress development without compromising the final properties of the dental composite

Luis Felipe J. Schneider, Simonides Consani, Ronald L. Sakaguchi, Jack L. Ferracane

Research output: Contribution to journalArticle

26 Scopus citations


Objectives: Stress development during the polymerization process continues to be a major factor that limits predictability and longevity of resin composite restorations. This study evaluated the effect of the photoinitiator type on the maximum rate of polymerization (Rpmax), stress development (final stress and maximum rate, Rstressmax), degree of conversion (DC) and cross-link density (CLD) of materials containing camphorquinone (CQ), phenylpropanedione (PPD) or CQ/PPD. Materials and methods: Rpmax was evaluated via differential scanning calorimetry (DSC). Contraction force measurement was assessed with a single cantilever device for 5 min. The samples were subsequently tested by infrared spectroscopy (FTIR) to evaluate the DC. After, samples were soaked in ethanol to evaluate the swelling coefficient (α) as a way to estimate the CLD. The results were analyzed by one-way ANOVA and Tukey's test (p = 0.05). Results: CQ showed the highest Rpmax and Rstressmax. PPD produced the lowest DC and the highest α. The mixture CQ/PPD produced statistically lower Rpmax and Rstressmax than CQ alone, but similar DC and CLD. Conclusion: CQ/PPD reduced the Rpmax and Rstressmax without a reduction in DC and CLD. Therefore, the use of alternative photoinitiator systems could be a promising way to reduce the stress developed during the composite's polymerization without affecting the final properties.

Original languageEnglish (US)
Pages (from-to)566-572
Number of pages7
JournalDental Materials
Issue number5
StatePublished - May 1 2009



  • Composites
  • Degree of conversion
  • Photoinitiators
  • Polymerization stress

ASJC Scopus subject areas

  • Materials Science(all)
  • Dentistry(all)
  • Mechanics of Materials

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