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BackgroundBleached dental enamel can be more susceptible to staining than the enamel that has never been bleached, especially right after tooth bleaching. The aim of this study is to evaluate the effect of surface treatments and waiting time prior to contact with dye on bleached enamel staining susceptibility.Material and MethodsOne hundred teeth were bleached with 35% hydrogen peroxide (Whiteness HP, FGM) and randomly assigned to G1 artificial saliva, G2 2% sodium fluoride (Flugel, Nova DFL), G3 casein phosphopeptide-amorphous calcium phosphate fluoride paste (CPP-ACPF, MI Paste Plus, GC America), G4 rinse for color maintenance after bleaching (Keep White Rinse, DMC) and G5 polishing with aluminum oxide-impregnated disks (Super Buff Disk, Shofu). Fifty specimens were immersed in red wine for 15 minutes, immediately after treatment, and the others one hour after. Color difference (∆E) was evaluated with a spectrophotometer (Vita EasyShade). Surface treatments and waiting time effects were analyzed with Kruskal-Wallis and Mann Whitney tests (p<0.05).ResultsSurface treatments (p>0.05) and waiting time (p>0.05) were not significant to decrease bleached enamel susceptibility to red wine staining.ConclusionsSurface treatments were similar to artificial saliva for bleached enamel susceptibility to red wine staining. Immediate or one-hour-postponed contact with red wine did not affect bleached enamel color. Key words:Tooth bleaching, color, dental enamel, hydrogen peroxide, pigmentation.

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This study goal is to present a case report of tooth bleaching treatment with the combination of the custom tray and in-office techniques, and to discuss about the considerations for result maintenance. A treatment approach was planned involving exogenous bleaching with custom trays with 7.5% hydrogen peroxide, and in-office bleaching with 35% hydrogen peroxide. The in-office bleaching agent was applied in two 15-minute applications, without led light. The patient was instructed to use the custom trays only a day after, with one drop of the bleaching agent for each tooth space. After the application of the bleaching agent, the patient used the trays for 1 hour per day, continuously for 30 days, 15 days for each arch. Considering the executed treatment approach, we may conclude that when correctly indicated, tooth bleaching with the combination of the in-office and custom trays techniques can be an acceptable choice of treatment, capable of enhancing the smile esthetics with a simple technique that preserves the sound dental structure. The patient should be instructed for the maximum color preservation and esthetic result maintenance, and should be advised that retreatments may become necessary depending on the oral hygiene and frequence of coloured food and drinks intake.

Background The increasing demand of tooth bleaching has also increased the need of researches focusing on the durability of the resultant color. The aim of this study was to evaluate the effect of a system based on calcium silicate, sodium phosphate and sodium monofluorophosphate (Regenerate™) on color maintenance of bleached enamel considering two waiting times for the contact with a cola drink. Material and Methods This in vitro study was performed on bovine enamel specimens (n = 100), bleached with 35% H2O2 and treated with: G1 Distilled water; G2 Artificial saliva; G3 RegenerateTM Serum and Toothpaste; G4 RegenerateTM Toothpaste; G5 RegenerateTM Serum. The groups G3, G4 and G5 received one application of the respective products for 3 min, in 3 consecutive days. The color parameters (ΔE, L*, a*, b*) were evaluated by spectrophotometry before and after bleaching and after surface treatments and immersion (15min) in cola drink, on the waiting times of 24 hours (T1) and 7 days (T2). The effect of surface treatments and waiting times was evaluated by Two-Way ANOVA, Kruskal-Wallis, Wilcoxon and T test ( p <0.05). Results There was no significant effect of the surface treatments ( p =0.57), waiting times ( p =0.97) and their interaction ( p =0.47) considering ΔE. The analysis of repeated measures of the color coordinates L*, a* and b* showed a decrease of chromaticity (a*, b*) for G3, G4 and G5 and an increase of lightness (L*) for G5, after immersion in cola drink, suggesting some protection against bleached enamel pigmentation. Conclusions RegenerateTM has a potential protective effect on bleached enamel color maintenance. The waiting times of 24 hours and 7 days for the contact with the cola drink did not influence bleached enamel color maintenance. Key words: Tooth bleaching, hydrogen peroxide, spectrophotometry, pigmentation.