title: An in vitro comparison of the bleaching efficacy of 35% carbamide peroxide with established intracoronal bleaching agents.
abstract: OBJECTIVE
  To evaluate the bleaching efficacy of 35% carbamide peroxide, 35% hydrogen peroxide and sodium perborate for intracoronal bleaching of root filled discoloured teeth.
  
  
  METHODS
  Extracted premolars were artificially stained using whole blood then root canal treatment was performed. After obturation, a 2 mm intermediate base was placed 1 mm below the buccal amelo-cemental junction. Intracoronal bleaching was performed in 11 teeth per group, using either 35% carbamide peroxide gel (group CP), 35% hydrogen peroxide gel (group HP) or sodium perborate mixed with distilled water (group SP). The bleaching agents were replaced after 7 days. The shade of the teeth was evaluated at day 0, 7 and 14. The results were analysed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U-test.
  
  
  RESULTS
  At the end of 7 days, both groups CP and HP lightened by 8 +/- 3 Vita tab positions, respectively, whereas group SP lightened by 5 +/- 3 tab positions (P < 0.05). At the end of the second bleaching period at day 14, group CP and HP lightened by a further 2 +/- 2 and 2 +/- 3 tab positions, respectively, whereas group SP lightened by a further 3 +/- 4 tab positions. There were no statistical differences between groups at day 14.
  
  
  CONCLUSIONS
  Thirty-five per cent carbamide peroxide and 35% hydrogen peroxide were equally effective for intracoronal bleaching, and significantly better than sodium perborate after 7 days. After 14 days, there were no significant differences between the groups. Thirty-five per cent carbamide peroxide can be recommended as an equally effective alternative to hydrogen peroxide for intracoronal bleaching.
authors.affiliation: Faculty of Dentistry, National University of Singapore, Singapore.
authors.forename: M Y
authors.initials: MY
authors.lastname: Lim
authors.forename: S O Y
authors.initials: SO
authors.lastname: Lum
authors.forename: R S C
authors.initials: RS
authors.lastname: Poh
authors.forename: G P
authors.initials: GP
authors.lastname: Lee
authors.forename: K-C
authors.initials: KC
authors.lastname: Lim
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001641:Bicuspid; D001881:Borates / Q000008:administration & dosage; D000077463:Carbamide Peroxide; D002648:Child; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage; D016877:Oxidants / Q000008:administration & dosage*; D010545:Peroxides / Q000008:administration & dosage*; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching / Q000379:methods*; D014075:Tooth Discoloration / Q000188:drug therapy; D014508:Urea / Q000008:administration & dosage* / Q000031:analogs & derivatives*
chemical_list: D001881:Borates; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; C027707:sodium perborate