title: In vitro effects of hydrogen peroxide combined with different activators for the in-office bleaching technique on enamel.
abstract: OBJECTIVE
  The aim of this study was to evaluate the alteration of human enamel bleached with high concentrations of hydrogen peroxide associated with different activators.
  
  
  METHODS
  Fifty enamel/dentin blocks (4 × 4 mm) were obtained from human third molars and randomized divided according to the bleaching procedure (n = 10): G1 = 35% hydrogen peroxide (HP - Whiteness HP Maxx); G2 = HP + Halogen lamp (HL); G3 = HP + 7% sodium bicarbonate (SB); G4 = HP + 20% sodium hydroxide (SH); and G5 = 38% hydrogen peroxide (OXB - Opalescence Xtra Boost). The bleaching treatments were performed in three sessions with a 7-day interval between them. The enamel content, before (baseline) and after bleaching, was determined using an FT-Raman spectrometer and was based on the concentration of phosphate, carbonate, and organic matrix. Statistical analysis was performed using two-way ANOVA for repeated measures and Tukey's test.
  
  
  RESULTS
  The results showed no significant differences between time of analysis (p = 0.5175) for most treatments and peak areas analyzed; and among bleaching treatments (p = 0.4184). The comparisons during and after bleaching revealed a significant difference in the HP group for the peak areas of carbonate and organic matrix, and for the organic matrix in OXB and HP+SH groups. Tukey's analysis determined that the difference, peak areas, and the interaction among treatment, time and peak was statistically significant (p < 0.05).
  
  
  CONCLUSIONS
  The association of activators with hydrogen peroxide was effective in the alteration of enamel, mainly with regards to the organic matrix.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas - FOP/Unicamp , Piracicaba, SP , Brazil.
authors.forename: Débora Alves Nunes Leite
authors.initials: DA
authors.lastname: Lima
authors.forename: Flavio Henrique Baggio
authors.initials: FH
authors.lastname: Aguiar
authors.forename: Núbia Inocencya Pavesi
authors.initials: NI
authors.lastname: Pini
authors.forename: Luis Eduardo Silva
authors.initials: LE
authors.lastname: Soares
authors.forename: Airton Abrahão
authors.initials: AA
authors.lastname: Martin
authors.forename: Priscila Christiane Suzy
authors.initials: PC
authors.lastname: Liporoni
authors.forename: Glaucia Maria Bovi
authors.initials: GM
authors.lastname: Ambrosano
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Lovadino
mesh_terms: D002244:Carbon / Q000032:analysis; D002254:Carbonates / Q000032:analysis; D003743:Dental Enamel / Q000737:chemistry / Q000187:drug effects*; D006801:Humans; D006860:Hydrogen Bonding; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D006878:Hydroxides / Q000494:pharmacology; D008422:Materials Testing; D010710:Phosphates / Q000032:analysis; D010778:Photochemotherapy / Q000295:instrumentation; D017680:Potassium Compounds / Q000494:pharmacology; D011897:Random Allocation; D017693:Sodium Bicarbonate / Q000494:pharmacology; D012972:Sodium Hydroxide / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000494:pharmacology*
chemical_list: D002254:Carbonates; D006878:Hydroxides; D010710:Phosphates; D017680:Potassium Compounds; D058205:Tooth Bleaching Agents; D012972:Sodium Hydroxide; D002244:Carbon; D017693:Sodium Bicarbonate; D006861:Hydrogen Peroxide; C029943:potassium hydroxide
keywords: Bleaching; FT-Raman; enamel; hydrogen peroxide