title: pH-changes during intracoronal bleaching: an in vivo study.
abstract: OBJECTIVE
  This study aimed to measure pH changes during 14 days intracoronal bleaching with hydrogen peroxide/sodium perborate and carbamide peroxide/sodium perborate.
  
  
  METHODS
  Twenty patients presenting endodontically treated central maxillary incisors with color alterations were divided in two groups (n = 10): Group CP + SP: 37% carbamide peroxide + sodium perborate paste; Group HP + SP: 30% hydrogen peroxide + sodium perborate paste. The pH values were measured using a digital microprocessor at different times: Baseline, 2, 7 and 14 days. Data were analyzed with two-way ANOVA followed by Tukey's test (α = 0.05).
  
  
  RESULTS
  ANOVA showed p < 0.00 which indicated significant difference between the groups. The mean values (± sd) and the results of the Tukey´s test were: HP + SP/14 days-7.98 (±0.58)a; HP + SP/7 days-8.59 (±0.18)b; HP + SP/2 days- 8.83 (±0.32)bc; HP + SP/Baseline-8.83 (±0.01)bc; CP + SP/ Baseline-8.89 (±0.01)bc; CP + SP/14 days-9.11 (±0.58)cd; CP + SP/7 days-9.54 (±0.16)de; CP + SP/2 days-9.66 (±0.08) de. The group HP + SP resulted in significantly lower pH values compared with group CP + SP.
  
  
  CONCLUSIONS
  It can be concluded that both associations showed alkaline pH values; however, there was significant reduction in the pH values of the 30% hydrogen peroxide associated with sodium perborate after 14 days.
  
  
  CONCLUSIONS
  The association of hydrogen peroxide and carbamide peroxide with sodium perborate paste presented alkaline characteristics during the 14-day evaluated period. Thus, regarding pH changes, both associations can be considered safe as intracoronal bleaching agents.
authors.affiliation: Department of Restorative Dentistry, São Josédos Campos School of Dentistry, São Paulo State University, São Paulo, Brazil.
authors.forename: Daphne Camara
authors.initials: DC
authors.lastname: Barcellos
authors.forename: Alessandra Buhler
authors.initials: AB
authors.lastname: Borges
authors.forename: Regina Celia dos Santos Pinto
authors.initials: RC
authors.lastname: Silva
authors.forename: Luciana Maria
authors.initials: LM
authors.lastname: Ribeiro
authors.forename: Cesar Rogerio
authors.initials: CR
authors.lastname: Pucci
authors.forename: Carlos
authors.initials: C
authors.lastname: Rocha Gomes Torres
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001881:Borates / Q000737:chemistry; D000077463:Carbamide Peroxide; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D010545:Peroxides / Q000737:chemistry; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000737:chemistry*; D019553:Tooth, Nonvital; D014508:Urea / Q000031:analogs & derivatives / Q000737:chemistry; D055815:Young Adult
chemical_list: D001881:Borates; D004338:Drug Combinations; D010545:Peroxides; D058205:Tooth Bleaching Agents; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; C027707:sodium perborate