Effect of Bleaching Agents on the Roughness of Bovine Enamel

Objectives: this study evaluated the effect of three bleaching agents on the surface roughness of bovine enamel: 10% carbamide peroxide (CP), 16% CP and 35% hydrogen peroxide (HP). Methods: enamels fragments (5mmX5mm) were embedded in epoxy resin, polished and divided into 4 groups (n=10): G1= artificial saliva (control); G2=10% CP (Whiteness Perfect 10%, FGM); G3= 16% CP (Whiteness Perfect 16%, FGM); G4=35% HP (Whiteness HP, FGM). Initial surface roughness (I) of each specimen was measured by the average of 3 values using a surface test (Mitutoyo, Japan). G2 and G3 were exposed to 4h, daily, during 14 days. On G4, bleaching agent was applied for 3 min, followed by 1.5 min irradiation with a blue LED system [ë = 470nm/ 0.5W/cm2 (Whitening Lase, DMC)], remained on the specimens for 3 min more, 3 times in the same session with 5 days intervals. After bleaching, specimens were stored in artificial saliva. After 14 days, final surface roughness (F) was measured. Results: data were submitted to ANOVA, which revealed no significant difference among the groups: G1(I)= 0.044µm; G1(F)= 0.047µm; G2(I)= 0.056µm; G2(F)= 0.055µm; G3(I)= 0.046µm; G3(F)= 0.044µm; G4(I)= 0.044µm; G4(F)= 0.050µm. Conclusions: there is no evidence to suggest that 10% CP, 16% CP and 35% HP cause significant changes in the surface roughness of bovine enamel.