title: Effect of bleaching on the cemento-enamel junction.
abstract: OBJECTIVE
  To evaluate the effect of various bleaching agents on the cemento-enamel junction (CEJ) of human teeth by scanning electron microscopy (SEM) analysis.
  
  
  METHODS
  30 intact teeth were selected and longitudinally sectioned, yielding 60 specimens. Thirty specimens served as controls; the other 30 were divided into six groups with five specimens each (n = 5) and bleached according to six protocols (Group 1: External bleaching with 10% carbamide peroxide; Group 2: External bleaching with 35% hydrogen peroxide; Group 3: External bleaching with 35% hydrogen peroxide; Group 4: Internal/external bleaching with 35% hydrogen peroxide; Group 5: Internal/external bleaching with 35% hydrogen peroxide; and Group 6: Intracoronal bleaching with a paste of sodium perborate mixed with 9% hydrogen peroxide). After treatment the specimens were prepared and examined in a scanning electron microscope.
  
  
  RESULTS
  The bleaching agents used in this study caused morphological changes in the CEJ and increased dentin exposure.
authors: Department of Pathology, Bauru Dental School, University of São Paulo, Brazil. roesberard@hotmail.com
authors: Roberta
authors: R
authors: Esberard
authors: Renata R
authors: RR
authors: Esberard
authors: Roberto M
authors: RM
authors: Esberard
authors: Alberto
authors: A
authors: Consolaro
authors: Cornelis H
authors: CH
authors: Pameijer
mesh_terms: D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects / Q000648:ultrastructure; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000627:therapeutic use*; D016877:Oxidants / Q000627:therapeutic use*; D010545:Peroxides / Q000627:therapeutic use*; D018709:Statistics, Nonparametric; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D019237:Tooth Cervix / Q000187:drug effects*; D014508:Urea / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide