Abstract
This study evaluated the influence of different enamel thicknesses and bleaching agents on treatment efficacy in-depth by spectrophotometry color analysis. Eighty bovine dental fragments were previously stained in black tea solution and randomly assigned into eight groups (n=10), 1.75mm dentin thickness and different enamel thicknesses as follows: 0.5mm, 1.0mm planned, 1.0mm unplanned (aprismatic enamel), and absence of enamel. The 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching gels were applied on the enamel surface following the manufacturer's recommendations. Color of underlying dentin was evaluated at four times: after staining with tea (baseline) and after each one of the three weeks of bleaching treatment, by CIE L*a*b* system using reflectance spectrophotometer (CM 700d, Konica Minolta). The ΔE, ΔL, Δa, and Δb values were recorded and subjected to repeated measures ANOVA and Tukey’s test (α=0.05). The results showed an increase on lightness (L*), with decreased redness (a*) and yellowness (b*). At first and second week, bleaching with CP showed higher whitening effectiveness compared to bleaching with HP and the presence of aprismatic enamel significantly reduced ΔE for bleaching with CP. After three weeks of bleaching, few differences were observed between CP and HP groups, and outer enamel layer caused no influence on bleaching effectiveness. Overall, both at-home and in-office bleaching treatments were effective and the presence of aprismatic enamel did not interfere on the whitening efficacy.
Highlights
Tooth bleaching is a conservative and esthetic treatment for dental discoloration, which acts on the removal of pigments present in the tooth structure, making it whiter [1]
This study evaluated the influence of different enamel thicknesses and bleaching agents on the whitening efficacy in-depth, by using bovine tooth block previously stained with black tea
Reaction products involving carbamide peroxide (CP) and hydrogen peroxide (HP) are same, i.e., oxygen-free radicals, studies have reported that action mechanism of these two agents is different, since the peroxide breakdown reaction resulting in radical releasing occurs differently
Summary
Tooth bleaching is a conservative and esthetic treatment for dental discoloration, which acts on the removal of pigments present in the tooth structure, making it whiter [1]. These dental discolorations are result of the deposition of intrinsic or extrinsic chromogenic pigments. The intrinsic discoloration is caused by the incorporation of chromogens components within the tooth structure during odontogenesis or after the tooth eruption. Both carbamide and hydrogen peroxide have been used for dental bleaching with various techniques and concentrations. Bleaching agents haves hydrogen peroxide as active component, which can be applied
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