In vitro effects of hydrogen peroxide combined with different activators for the in-office bleaching technique on enamel
Lima, Débora.Alves.Nunes.Leite.; Aguiar, F.Henrique.Baggio.; Pini, Núbia.Inocencya.Pavesi.; Soares, L.Eduardo.Silva.; Martin, A.Abrahão.; Liporoni, P.Christiane.Suzy.; Ambrosano, G.Maria.Bovi.; Lovadino, Jé.Roberto.
Acta Odontologica Scandinavica 73(7): 516-521
ISSN/ISBN: 0001-6357 PMID: 25626117 DOI: 10.3109/00016357.2014.997793
The aim of this study was to evaluate the alteration of human enamel bleached with high concentrations of hydrogen peroxide associated with different activators. 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. 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). The association of activators with hydrogen peroxide was effective in the alteration of enamel, mainly with regards to the organic matrix.