title: Combined Bleaching Technique Using Low and High Hydrogen Peroxide In-Office Bleaching Gel.
abstract: OBJECTIVE
  The aim of this study was to evaluate the efficacy, color stability, risk, and intensity of tooth sensitivity (TS) of combined bleaching techniques performed with 20% or 35% hydrogen peroxide for an in-office protocol.
  
  
  METHODS
  Thirty patients were randomly divided into two groups and submitted to a single 45-minute in-office bleaching session with 35% hydrogen peroxide or 20% hydrogen peroxide. At-home bleaching was performed with 10% carbamide peroxide for two hours daily over the course of two weeks. The color was evaluated with the value-oriented shade guide Vita Classical at different periods up to 12 months after bleaching. Patients recorded the intensity of TS using a five-point verbal scale. Color change data were submitted to a two-way repeated-measures analysis of variance and Tukey test (α=0.05). The absolute risk and intensity of TS were compared with the Fisher exact test and Mann-Whitney test, respectively (α=0.05).
  
  
  RESULTS
  On average, an effective and similar whitening of three units in shade guide was observed for both groups, which remained stable for 12 months. When both protocols were compared, the one with hydrogen peroxide 35% showed a higher risk (p=0.02) and intensity of TS (p=0.04). In regard to the TS intensity, no significant difference was observed up to 48 hours after in-office bleaching (p=0.09) and during the at-home bleaching phase of the study (p=0.71).
  
  
  CONCLUSIONS
  The combined bleaching technique using at-home bleaching associated with in-office bleaching was effective and stable over the course of 12 months, regardless of the concentration of the hydrogen peroxide used for in-office bleaching. However, the protocol with 20% hydrogen peroxide produced lower risk and intensity of TS.
authors.forename: M
authors.initials: M
authors.lastname: Rezende
authors.forename: L
authors.initials: L
authors.lastname: Ferri
authors.forename: S
authors.initials: S
authors.lastname: Kossatz
authors.forename: A D
authors.initials: AD
authors.lastname: Loguercio
authors.forename: A
authors.initials: A
authors.lastname: Reis
mesh_terms: D000293:Adolescent; D000328:Adult; D003116:Color; D003807:Dentin Sensitivity; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008297:Male; D010545:Peroxides; D014073:Tooth Bleaching; D058205:Tooth Bleaching Agents / Q000494:pharmacology*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010545:Peroxides; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide