title: Effects of dental bleaching on micro- and nano-morphological alterations of the enamel surface.
abstract: OBJECTIVE
  To investigate the effects of dental bleaching on the enamel surface micromorphology using SEM and TEM.
  
  
  METHODS
  Fine-polished enamel slabs were randomly divided into eight groups (n = 3). Unbleached specimens served as control (1). The enamel slabs were bleached either with home Illuminé 15% for 8 hours per day, over 7 days (2), 14 days (3), 28 days (4), and 42 days (5) or with Whitestrips for 30 minutes each time, for 14 times (6), 28 times (7) and 42 times (8). The micromorphological surface pattern of the specimens was analyzed by SEM. In addition, two specimens per group (1, 2 and 6) were embedded and analyzed by TEM.
  
  
  RESULTS
  SEM and TEM findings revealed that dental bleaching with carbamide peroxide or H2O2 over short periods of time (Groups 2, 6) caused nanomorphological alterations of the enamel surface, whereas prolonged exposure to the bleaching agents resulted in micromorphological changes of the enamel surface. Due to the bleaching process, the thickness of the enamel smear layer was significantly reduced.
authors: Department of Stomatology, No. 1 Hospital aff. to Medical College, Zhejiang University, Qingchun Road 79, Hangzhou 310003, China. baiping_fu@yahoo.com
authors: Baiping
authors: B
authors: Fu
authors: Wiebke
authors: W
authors: Hoth-Hannig
authors: Matthias
authors: M
authors: Hannig
mesh_terms: D000077463:Carbamide Peroxide; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D004338:Drug Combinations; D006801:Humans; D006813:Humidity; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D016877:Oxidants / Q000494:pharmacology*; D010545:Peroxides / Q000494:pharmacology; D016369:Smear Layer; D013696:Temperature; D013997:Time Factors; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C488279:Crest whitestrips; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide