title: Synthesis of metal ion-histidine complex functionalized mesoporous silica nanocatalysts for enhanced light-free tooth bleaching.
abstract: Several metal ion-histidine complex functionalized mesoporous silica nanoparticles (MSN) were synthesized and utilized as efficient catalysts for enhanced and light-free tooth bleaching. Fe(II), Mn(II), and Cu(II) ions were successfully immobilized in histidine-functionalized MSN and their catalytic abilities against discoloration of a dye (Orange II) in both test tubes and extracted tooth models were compared and discussed. Through direct observation of test tubes and calculation of mean color changes of extracted teeth we concluded that Fe(II)-his-MSN exhibited better catalytic competence than Mn(II)-his-MSN and Cu(II)-his-MSN because of its intrinsic redox ability. In test tubes Orange II was completely degraded within 6 h when Fe(II)-his-MSN was used as the catalyst. For the extracted tooth model the presence of Fe(II)- or Mn(II)-his-MSN significantly enhanced the efficacy of tooth bleaching for three regions, the enamel, outer dentin, and inner dentin, of stained teeth compared with H(2)O(2) alone. Furthermore, unlike current tooth bleaching techniques that need an LED or laser to catalyze H(2)O(2) bleaching, we demonstrated a light-free tooth bleaching system using Fe(II)-his-MSN as an efficient and reliable catalyst.
authors.affiliation: Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Bor-Shiunn
authors.initials: BS
authors.lastname: Lee
authors.forename: Li-Chun
authors.initials: LC
authors.lastname: Huang
authors.forename: Chen-Yu
authors.initials: CY
authors.lastname: Hong
authors.forename: Shy-Guey
authors.initials: SG
authors.lastname: Wang
authors.forename: Wei-Hang
authors.initials: WH
authors.lastname: Hsu
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Chia-Jung
authors.initials: CJ
authors.lastname: Hsieh
authors.forename: Juin-Yih
authors.initials: JY
authors.lastname: Lai
authors.forename: Kevin C-W
authors.initials: KC
authors.lastname: Wu
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry; D001557:Benzenesulfonates / Q000737:chemistry; D002384:Catalysis / Q000528:radiation effects; D003116:Color; D006639:Histidine / Q000138:chemical synthesis*; D007477:Ions; D008027:Light; D008670:Metals / Q000138:chemical synthesis*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009584:Nitrogen / Q000737:chemistry; D016062:Porosity / Q000528:radiation effects; D012822:Silicon Dioxide / Q000138:chemical synthesis*; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014073:Tooth Bleaching / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D007477:Ions; D008670:Metals; D006639:Histidine; D012822:Silicon Dioxide; D009584:Nitrogen; C014722:2-naphthol orange