Dental Bleaching with 35 and 38% Hydrogen Peroxide and Immersion in Soft Drink: Analysis by Reflectance and Fourier Transform-Raman Spectroscopy

Abstract

ABSTRACT Objective The aim of this study was to evaluate the effects of dental bleaching with 35 and 38% hydrogen peroxide and soft drink immersion on the chemistry and color of the bovine enamel fragments before and after treatment using reflectance and Fourier transform-Raman spectroscopy (FT-Raman spectroscopy). Materials and methods Sixty bovine enamel fragments were prepared and randomly divided into six experimental groups according to the hydrogen peroxide gel concentration or immersion in soft drink (n = 10): G1-Whiteness HP Maxx; G2-Whiteness HP Maxx + light lemon coke immersion; G3-Opalescence Xtra Boost; G4-Opalescence Xtra Boost + light lemon coke immersion; G5-Whiteform Perox Red Form gel; G6-Whiteform Perox Red Form gel + light lemon coke immersion. The bleaching treatment was performed in two sessions with a 7 days interval and the analysis before treatments were used as control (baseline). Samples were submitted to reflectance and FT-Raman spectroscopy analysis to evaluate surface mineral content and the reflectance before and after treatments. Results There was no significant statistical difference among the bleaching agents in the reflectance analysis (p = 0.63). The FT-Raman spectroscopy data showed significant loss in enamel mineral content after immersion in the light lemon coke and statistical significant differences for the interactions between ‘bleaching agent’ and ‘immersion in soft drink’ (p = 0.03) and between ‘bleaching agent’ and ‘time’ (p = 0.04). With regards to the whitened specimens, the Opalescence Xtra Boost agent demonstrated the greatest loss in enamel mineral content. Conclusion All bleaching agents exhibited great bleaching potential in reflectance analysis. This highly concentrated hydrogen peroxide gel (38%) changed significantly the enamel mineral content with or without immersion in soft drink. The specimens immersed in soft drink showed significant loss in enamel mineral content. Clinical relevance Some investigations have shown that hydrogen peroxide and beverages can modify enamel dental components, but more studies are necessary to explain its effects.