title: Evaluating a Cobalt-Tetraphenylporphyrin Complex, Functionalized with a Reduced Graphene Oxide Nanocomposite, for Improved Tooth Whitening.
abstract: To study using cobalt-tetraphenylporphyrin/reduced graphene oxide (CoTPP/RGO), a nanocomposite highly catalytic both for oxidizing and for reducing hydrogen peroxide (H2O2), to whiten teeth.
  
  
  
  Dyes (D&C Red 34, Orange No. 4), tea, and betel nuts (Areca catechu) were used to stain the tooth specimens for three days and subsequently bleached using H2O2alone, H2O2plus CoTPP, or H2O2plus CoTPP/RGO for 0.5-70 hours. The process was photographed using an electronic chromometer and a camera. Color change was assessed after each session. The results of bleaching teeth with and without photoirradiation were compared.
  
  
  
  CoTPP/RGO increased the tooth-whitening efficacy of H2O2for specimens stained with dyes, tea, and betel nuts. Using lamps (photoactivation) (wavelengths: 254 nm and 310 nm) to catalyze the H2O2bleaching agent reduced the bleaching treatment time.
  
  
  
  First, the Co/TPP/RGO complex allows improved tooth bleaching and shorter treatment times. Second, because the Co/TPP/RGO complex bleached D&C Red 34 at a similar rate and to a similar degree as tea and other natural agents stain teeth, it is a convenient staining agent for studying many vital aspects of tooth bleaching. (J Esthet Restor Dent 28:321-329, 2016).
authors.affiliation: Department of Orthodontics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: I-Hsuan
authors.initials: IH
authors.lastname: Su
authors.affiliation: Yang-an Dental Clinic, Taipei, Taiwan.
authors.forename: Chen-Fu
authors.initials: CF
authors.lastname: Lee
authors.affiliation: Yang-an Dental Clinic, Taipei, Taiwan.
authors.forename: Yu-Pin
authors.initials: YP
authors.lastname: Su
authors.affiliation: Department of Medical Chemistry, Chia Nan University of Pharmacy and Science, 60 Erh-Jen Road, Section 1, Jen Te, Tainan, 71743, Taiwan. e201466wang@msa.hinet.net.
authors.forename: Lai-Hao
authors.initials: LH
authors.lastname: Wang
mesh_terms: D003035:Cobalt; D003116:Color; D006108:Graphite; D006861:Hydrogen Peroxide; D053761:Nanocomposites; D011166:Porphyrins; D013662:Tea; D014070:Tooth; D014073:Tooth Bleaching; D058205:Tooth Bleaching Agents; D014075:Tooth Discoloration
chemical_list: D011166:Porphyrins; D013662:Tea; D058205:Tooth Bleaching Agents; C409084:tetraphenylporphyrin; D003035:Cobalt; D006108:Graphite; D006861:Hydrogen Peroxide