title: Effects of light sources and visible light-activated titanium dioxide photocatalyst on bleaching.
abstract: The objective of this study was to evaluate, using methylene blue (MB), the effects of various light sources on the bleaching action of hydrogen peroxide (H(2)O(2)) with two titanium dioxide (TiO(2)) photocatalysts - an ultraviolet light-activated TiO(2) photocatalyst (UVTiO(2)) versus a visible light-activated TiO(2) photocatalyst (VL-TiO(2)). Five experimental solutions (VL-TiO(2)+H(2)O(2), UV-TiO(2)+H(2)O(2), H(2)O(2), VL-TiO(2), UV-TiO(2)) were prepared by mixing varying concentrations of H(2)O(2 )and/or TiO(2 )photocatalyst with MB solution. For H(2)O(2)-containing solutions (VL-TiO(2)+H(2)O(2), UV-TiO(2)+H(2)O(2), and H(2)O(2)), the concentration of H(2)O(2) was adjusted to 3.5%. For the four different light sources, low- and high-intensity halogen lamps and blue LED LCUs were used. All the experimental solutions were irradiated by each of the light sources for 7 minutes, and the absorbance at 660 nm was measured every 30 seconds to determine the concentration of MB as an indicator of the bleaching effect. On the interaction between the effects of light source and bleaching treatment, the high-intensity halogen with VL-TiO(2)+H(2)O(2) caused the most significant reduction in MB concentration. On the effect of light sources, the halogen lamps resulted in a greater bleaching effect than the blue LED LCUs.
authors.affiliation: Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan. worldclass0221@yahoo.co.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Suyama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Otsuki
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Ogisu
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Kishikawa
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.forename: Masaomi
authors.initials: M
authors.lastname: Ikeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kurata
authors.forename: Takahiro
authors.initials: T
authors.lastname: Cho
mesh_terms: D000042:Absorption; D004396:Coloring Agents; D055117:Curing Lights, Dental / Q000145:classification; D006801:Humans; D006861:Hydrogen Peroxide / Q000528:radiation effects / Q000627:therapeutic use; D008422:Materials Testing; D008751:Methylene Blue; D016877:Oxidants / Q000528:radiation effects / Q000627:therapeutic use; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D010789:Phototherapy; D013053:Spectrophotometry; D013997:Time Factors; D014025:Titanium / Q000627:therapeutic use*; D014073:Tooth Bleaching / Q000379:methods*; D014467:Ultraviolet Therapy
chemical_list: D004396:Coloring Agents; D016877:Oxidants; D017319:Photosensitizing Agents; C009495:titanium dioxide; D006861:Hydrogen Peroxide; D014025:Titanium; D008751:Methylene Blue