Development of a new photoinitiation system for dental light-cure composite resins

Y. J. Park, K. H. Chae, H. R. Rawls

Research output: Contribution to journalArticlepeer-review

178 Scopus citations


Objectives: The purpose of this study is to explore the synergistic effect of combining camphorquinone (CQ) with 1-phenyl-1,2-propanedione (PPD) as a new photoinitiator. Methods: A BisGMA, UDMA, TEGDMA monomer mixture was made light-curing with CQ and/or PPD plus 0.2 wt.% N,N-cyanoethylmethylaniline (CEMA). Seventeen groups, three specimens each, were tested in which the concentrations of PPD and CQ were varied. The effect of photosensitizer type (CQ or PPD) and ratio (PPD/CQ) on degree of conversion (DC) was investigated using FTIR spectrophotometry. The results were analyzed by ANOVA and Student-Newman-Keuls' multiple range comparison. The absorption spectra of PPD and CQ were recorded by UV-Vis spectrophotometry. A blind color comparison of specimens containing combinations of the two photosensitizers was also undertaken. Results: Alone, PPD induces a DC which is not significantly different from that of CQ alone. In combination, CQ + PPD produces a DC that generally exceeds that produced by the same concentration of either used alone. The maximum DC occurs between PPD/CQ = 1:1 and 1:4. At total photosensitizer concentrations above 1.8 wt.%, DC is increased by PPD but depressed by CQ, which is evidence that different mechanisms are involved. PPD (λmax ≈ 410 nm) and CQ (λmax ≈ 468 nm) have different wavelength absorption ranges, resulting in a perceptibly lighter shade of yellow for PPD. Significance: 1-phenyl-1,2-propanedione is a photosensitizer of potential value in reducing color problems associated with visible light cured dental resins. In combination with camphorquinone, it acts synergistically to produce a more efficient photoinitiation reaction.

Original languageEnglish (US)
Pages (from-to)120-127
Number of pages8
JournalDental Materials
Issue number2
StatePublished - Mar 1999


  • 1-phenyl-1,2-propanedione
  • Camphorquinone
  • Photopolymerization

ASJC Scopus subject areas

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


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