SUMMARY Purpose The objective of this study was to evaluate if the application method (tip with brush or tip without brush) and hydrogen peroxide (HP) concentration (6% or 35% self-mixing) of in-office bleaching gel influences the penetration of HP into the pulp chamber, color change, and the amount of bleaching gel used. Methods Forty healthy premolars were randomly divided into the following five groups (n=8): no treatment; HP6% using a tip with a brush, HP6% using a tip without a brush, HP35% using a tip with a brush, and HP35% using a tip without a brush. After treatments, the HP concentration (μg/mL) within the pulp chamber was determined using UV-Vis spectrophotometry. The color change (ΔEab, ΔE00, and ΔWID) was evaluated using a digital spectrophotometer. The amount of gel used (g) in each group was measured using a precision analytical balance. Data from each test were submitted to parametric tests (α=0.05). Results The tip with a brush resulted in a lower amount of HP inside the pulp chamber and less gel used when compared with the tip without a brush, regardless of HP concentration (p<0.05). However, regarding the tip used, although no significant difference was observed when HP35% was used (p>0.05), a higher whitening effect was observed when the 6% HP was applied without a brush as opposed to with a tip brush (p<0.05). Conclusions The use of a tip with a brush, regardless of the in-office bleaching gel concentration (6% or 35% self-mixing), presented a lower penetration and lower volume of spent gel when compared to a tip without brush. However, the whitening effect depends on the concentration of HP used.

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Objective Our randomized, parallel and single‐blinded clinical trial evaluated patient level of discomfort during at‐home bleaching testing the equivalence between two different protocols for the use of bleaching trays (simultaneous vs. single arch), as well as tooth sensitivity (TS), gingival irritation, (GI) and bleaching efficacy (BE). Materials and Methods We randomized 100 patients into: simultaneous (n = 50) and single arch (n = 50). At‐home bleaching was performed with 10% hydrogen peroxide (HP) for 2 weeks for simultaneous group and 4 weeks for single arch group. We assessed patient level of discomfort using 9‐item questionnaire. The TS and GI, as well as BE using spectrophotometer and color guide were assessed using the visual analog scale (0–10). Data from level of discomfort and BE were evaluated by Student's t test. The TS and GI were compared using the relative risk and confidence interval (α = 0.05). Results Only tray adaptation showed a significant effect after the second week (p < 0.002). There was equivalence between groups for level of discomfort (p < 0.01). We found no significant intergroup differences for the risk of TS or GI, nor for intensity. We observed no significant differences between them regarding bleaching efficacy (p > 0.21). Conclusions A simultaneous‐use protocol for customized at‐home dental bleaching trays proved to be equivalent to using single arch for patient level of discomfort and bleaching efficacy, with no significant increase in adverse effects. Clinical Significance Clinicians may decide whether to use a simultaneous or single arch protocol for tray usage; however, bleaching was achieved more quickly when the trays were worn simultaneously.

Purpose This study aimed to quantify the penetration of hydrogen peroxide (HP) inside the pulp cavity and color change with two different concentrations of HP to at‐home bleaching associated or not with enamel microabrasion (MA). Methods Forty healthy premolars were randomly divided in four groups (n = 10): only HP4%, MA + HP4%, only HP10%, MA + HP10%. The concentration (μg/ml) of HP was assessed using UV–Vis spectrophotometry. The color change (ΔEab, ΔE00 and WID) was evaluated before and one‐week after bleaching. Data were evaluated for a two‐way ANOVA and the Tukey's test (α = 0.05). Results The application of MA increased the amounts of HP inside the pulp chamber when compared to without MA, as well as PH10% when compared to PH4% (p < 0.0001). PH10% showed higher WID when compared to PH4%. No significant difference was observed when ΔEab, and ΔE00 were used. Conclusions The enamel MA before at‐home bleaching promotes greater penetration of HP, although this procedure did not significantly affect the color change. Clinical Significance Since greater penetration of HP into the pulp chamber was detected when home bleaching was applied immediately after MA, the clinician should not apply home bleaching gels in the same session when MA was performed.