Evaluation of home bleaching gel modified by different thickeners on the physical properties of enamel: An in situ study

OBJECTIVE: This in situ study evaluated the influence of 10% carbamide peroxide (CP) in combination with different thickeners on physical characteristics of enamel. MATERIALS AND METHODS: Eighty-four bovine blocks of enamel and dentin (4 mm × 4 mm × 2.5 mm) were divided into seven groups (n = 12), fixed in palatal intraoral devices, and submitted to different treatments: CP + carbopol (FGM), CP + carbopol + glycerin (ultradent), CP + natrosol (experimental gel), carbopol, carbopol + glycerin, and natrosol, without treatment (control group). The physical properties tested were color (ΔE), roughness (Ra), and Knoop microhardness (KHN). STATISTICAL ANALYSIS USED: Data were submitted to ANOVA, Tukey's, and Dunnett's tests (α = 0.05). Results: all groups presented significant color variation, except carbopol. For microhardness, all bleached groups did not differ from control. Roughness increased in all bleached groups when compared to the control group, but CP + natrosol presented statistical lower results than CP + carbopol. CONCLUSION: Replacement of carbopol by natrosol caused less change on roughness surface, at the same time yielding an effective whitening result.