In-Office Dental Bleaching Using 37% Carbamide Peroxide Versus 35% Hydrogen Peroxide: A Randomized, Double-Blind Clinical Trial

Objective: Compare the tooth sensitivity (TS) and bleaching efficacy (BE) of in-office dental bleaching performed with 35% hydrogen peroxide (HP) or 37% carbamide peroxide (CP).

Materials and methods: Sixty-six participants were randomly divided into two groups according to the bleaching gel applied to the right hemiarch: 35% HP, or 37% CP. TS was recorded immediately after, up to 1, 24, and 48 h after bleaching, using the VAS and NRS scales. BE was assessed before bleaching and 1 month after using color guide units (ΔSGUs) and a spectrophotometer (ΔE_ab, ΔE₀₀, and ΔWI_D). TS was assessed using McNemar's and paired t-test (VAS) or Wilcoxon signed rank (NRS). The paired t-test was used to analyze BE (α = 0.05).

Results: TS risk and intensity were lower for the 37% CP (p = 0.003 and p < 0.005). Despite significant differences between the groups after 1 month (ΔSGU and ΔE₀₀; p < 0.05), the color measurements of both groups exceeded the 50%:50% perceptibility/acceptability threshold.

Conclusion: In-office dental bleaching using 37% CP resulted in reduced risk and TS intensity, without prejudice to the BE.

Clinical relevance: The use of 37% CP for in-office dental bleaching could decrease TS risk and intensity without affecting BE.

Trial registration: ClinicalTrials.gov identifier: RBR-683qhf.