Abstract

AYRES, ANA PAULA ALMEIDA; BERGER, SANDRINE BITTENCOURT; ANDRE, CAROLINA BOSSO  and  GIANNINI, MARCELO. Microhardness evaluation of bovine enamel after take-home, in-office tooth whitening techniques, and the association techniques using low and high concentration of peroxides. RPG, Rev. pós-grad. [online]. 2012, vol.19, n.4, pp. 147-152. ISSN 0104-5695.

The objective of this study was to evaluate the effects of take-home bleaching using 16% carbamide peroxide (CP), in-office tooth whitening using 35 or 37.5% hydrogen peroxide (HP), or the association take-home and inoffice bleaching techniques on superficial microhardness of bovine enamel. The buccal surfaces of 70 bovine incisors were prepared for initial microhardness measurements and divided in 6 experimental and 1 unbleached control group (n = 10). The CPs were applied for 8 hours/daily during 14 days. The HPs were used in three appointments with 4-day intervals among sessions and this process was repeated 3 times (12 minutes each application). For the groups with the association of techniques, the bleaching protocol was: one session with HP plus 14 days of takehome bleaching. At the end of bleaching, the samples were submitted to the final hardness measurements. The data were analyzed by 2 ANOVA and Tukey test (5%). The take-home bleaching with 16% CP (Whitegold Home) and its association with Whitegold Office (HP 35%) reduced the enamel microhardness. The use of Pola Night (16% PC), Pola Office (37.5% HP) and their association did not alter the microhardness values. The reduction in enamel microhardness promoted by bleaching agents, as well as the association of techniques was product-dependent.

Keywords : Tooth bleaching; Hydrogen peroxide; Dental enamel; Hardness.