title: Effectiveness of carbamide peroxide and sodium perborate in non-vital discolored teeth.
abstract: OBJECTIVE
  To evaluate the efficacy of 16% carbamide peroxide gel (CP16%), tetrahydrate sodium perborate (SP) and mixture (CP16% + SP), in walking bleaching of non-vital discolored teeth.
  
  
  METHODS
  Sixty single-rooted human premolars with intact crowns were used and initial color was assessed using Vita shade guide and standardized photos. The teeth were stained using rabbit fresh blood for 18 days and photos of discolored teeth and color evaluation were performed. The teeth were divided into 4 groups (n= 15), according to bleaching agent used: G1) CP16% gel; G2) CP16% gel + SP; G3) SP + distilled water; G4: control. The bleaching agents were replaced twice at 7-day intervals for 21 days. All teeth were evaluated by two endodontists at days 0, 7, 14 and 21 and the color changes were assessed using Vita shade guide and standardized photos. The results were analyzed by Kruskal-Wallis and Dunn's tests (p=0.05).
  
  
  RESULTS
  The experimental groups presented statistically similar bleaching results (p>0.05) at the end of 7, 14 and 21 days. These groups presented significantly higher bleaching efficacy than control group (G4) (p<0.05). The mixture CP16% + SP promoted return of original color in 100% of teeth at the end of 21 days.
  
  
  CONCLUSIONS
  It was concluded that three bleaching agents were effective in bleaching of stained teeth with blood products, especially at the end of 21 days.
authors.affiliation: Department of Restorative Dentistry, Dental School of São José dos Campos, São Paulo State University, São José dos Campos, SP, Brazil.
authors.forename: Marcia Carneiro
authors.initials: MC
authors.lastname: Valera
authors.forename: Carlos Henrique Ribeiro
authors.initials: CH
authors.lastname: Camargo
authors.forename: Cláudio Antonio Talge
authors.initials: CA
authors.lastname: Carvalho
authors.forename: Luciane Dias
authors.initials: LD
authors.lastname: de Oliveira
authors.forename: Samira Esteves Afonso
authors.initials: SE
authors.lastname: Camargo
authors.forename: Cristiana Martins
authors.initials: CM
authors.lastname: Rodrigues
mesh_terms: D000818:Animals; D001641:Bicuspid; D001801:Blood Stains; D001881:Borates / Q000008:administration & dosage*; D000077463:Carbamide Peroxide; D004338:Drug Combinations; D006801:Humans; D016877:Oxidants / Q000008:administration & dosage*; D010545:Peroxides / Q000008:administration & dosage*; D011817:Rabbits; D014073:Tooth Bleaching / Q000379:methods*; D014075:Tooth Discoloration / Q000628:therapy*; D019553:Tooth, Nonvital; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D001881:Borates; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; C027707:sodium perborate