Effect of lights with various wavelengths on bleaching by 30% hydrogen peroxide

Minh Nguyet Luong, Masayuki Otsuki, Yasushi Shimada, Thwe Zin Ei, Yasunori Sumi, Junji Tagami

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The objective of this study was to evaluate the bleaching effect of light sources with various wavelengths using 30% hydrogen peroxide (HP) in vitro. The hematoporphyrin-stained paper was bleached with HP and irradiated for 10 min using LED light sources with 265, 310, 365, 405, or 450 nm respectively. In control group, HP was applied for 10 min without light irradiation. The bleaching procedure was repeated two times. The L*a*b* values of the samples before bleaching and after each bleaching step were measured using a colorimeter. Color changes of specimens were then calculated and statistically analyzed. There was an interaction between light sources and time of irradiation in the color change (p < 0.05). Time and light sources significantly affected ΔE and ΔL (p < 0.05). The light source of 256 nm showed the highest bleaching effect over time followed by that of 310 nm, which were statistically different from other groups (p < 0.001). The 365 nm, 450 nm groups, and control group showed low bleaching effect visually with no significant differences in ΔE and ΔL (p > 0.05). It was concluded that the wavelengths of the light sources affected the bleaching by HP. The 310-nm light can be a potential source for bleaching.

Original languageEnglish
Pages (from-to)901-906
Number of pages6
JournalLasers in Medical Science
Issue number5
Publication statusPublished - Jul 1 2019


  • Bleaching
  • Hydrogen peroxide
  • LED
  • Ultraviolet
  • Wavelength

ASJC Scopus subject areas

  • Surgery
  • Dermatology


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