Fourier transform-Raman and reflectance studies on dental enamel bleached with hydrogen peroxide activated using a light-emitting diode-laser system.

Objective: To evaluate the effects of 35% hydrogen peroxide bleaching on bovine teeth using reflectance and Fourier transform (FT)-Raman spectroscopy.
Background Data: Previous investigations have shown that hydrogen peroxide can modify dental components, but more studies are necessary to comprehend its effects.
Materials and Methods: Forty bovine enamel fragments (4.0x4.0x4.0 mm) were divided into four experimental groups according to the hydrogen peroxide gel manufacturer's application: G1-Whiteness HP Maxx, G2-Whiteness HP, G3-Whiteform- Perox Red Form, G4-Opalescence Xtra. All groups were activated using a light-emitting diode-laser system. The bleaching treatments were performed in two sessions with a 72-h interval between sessions. The reflectance and Raman analyses of the enamel samples were performed before and after bleaching. The analyses before treatments were used as control.
Results: Enamel reflectance was significantly greater after the bleaching in group G3 than in groups G1, G2, and G4 (p<0.01). FT-Raman spectroscopy data showed no significant chemical changes in the inorganic components for the tested groups (p>0.05). Hydrogen peroxide gel caused significant reduction of the dental organics associated with type I collagen vibration only in group G3 (p<0.05).
Conclusion: Under the conditions of this study, 35% hydrogen peroxide Whiteform-Perox Red Form gel, exhibited great bleaching potential. This highly concentrated hydrogen peroxide gel significantly changed the reflectance of enamel and dental organics without significant chemical changes in enamel phosphate and carbonate content.