Effect of in-office bleaching with 35% hydrogen peroxide with and without addition of calcium on the enamel surface.
This study aimed to evaluate effectiveness and effects of bleaching with 35% hydrogen peroxide with and without calcium on color, micromorphology, and the replacement of calcium and phosphate on the enamel surface. Thirty bovine enamel blocks (5.0 × 5.0 mm) were placed into the following groups: G1: artificial saliva (control); G2: 35% hydrogen peroxide gel without calcium (Whiteness HP Maxx-FGM); and G3: 35% hydrogen peroxide gel with calcium (Whiteness HP Blue-FGM). Three color measurements were performed with a spectrophotometer: untreated (baseline), after performing staining, and after application of bleaching agents. Calcium deposition on the enamel was evaluated before and after the application of bleaching agents using energy-dispersive X-ray spectrometry. The enamel surface micromorphology was observed under scanning electron microscopy. The pH of each product was measured. The data were subjected to one-factor analysis of variance (ANOVA), and any differences were analyzed using Tukey's test (P < 0.05). G3 showed greater variation in total color after the experiment than G2 and G1; there was no significant difference in calcium or phosphorus concentration before and after the experimental procedures; morphological changes were observed only in G2 and G3; and the pH values of the Whiteness HP Maxx and Whiteness HP Blue bleaching agents were 5.77 and 7.79, respectively. The 35% hydrogen peroxide with calcium showed greater bleaching potential, but the addition of calcium had no effect in terms of reducing morphological changes or increasing the calcium concentration on the enamel surface.
School of Dentistry, Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro Do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil.
Izadora Quintela Souza
IQ
de Moraes
School of Dentistry, Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro Do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil.
Lucas Nunes de Brito
LN
Silva
Department of Restorative Dentistry, School of Dentistry, Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro Do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil.
Isabel Cristina Celerino de Moraes
IC
Porto
Laboratório LEAP, Instituto De Química E Biotecnologia (IQB), Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro Do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil.
Cantídio Francisco
CF
de Lima Neto
Department of Cariology, School of Dentistry, Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro Do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil.
Natanael Barbosa
NB
Dos Santos
Department of Restorative Dentistry, School of Dentistry, Federal University of Alagoas, Campus AC Simões, Av. Lourival Melo Mota, S/N, Tabuleiro Do Martins, CEP: 57072-970, Maceió, Alagoas, Brazil.
Larissa Silveira de Mendonça
LS
Fragoso
D000818:Animals; D002118:Calcium / Q000032:analysis*; D002417:Cattle; D003743:Dental Enamel / Q000737:chemistry* / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000032:analysis*; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties / Q000187:drug effects*; D014073:Tooth Bleaching / Q000379:methods*
D010710:Phosphates; D006861:Hydrogen Peroxide; D002118:Calcium
EDX; hydrogen peroxide; scanning electron microscopy; tooth bleaching