Tooth sensitivity in different arches post in-office dental bleaching: A multicenter randomized controlled trial

To compare the risk and intensity of tooth sensitivity (TS) and gingival irritation (GI), as well as bleaching efficacy (BE) in the maxillary and mandibular arches after in-office dental bleaching.

90 participants were randomly into two groups according to the arch (maxillary or mandibular) in which the patient will first receive a 35 % hydrogen peroxide gel (2 sessions; 1 × 30 min; 1 week apart). TS and GI were recorded immediately after, up to 1 h, 24 h and 48 h after bleaching, using the 0-10 Visual Analogue Scale (VAS). BE was assessed before bleaching and 30 days after the end of the treatment (shade guide units [ΔSGU], CIELab [ΔE_ab], CIEDE2000 [ΔE₀₀]_, and Whiteness Index for Dentistry [WI_D]). TS and GI were compared using McNemar's and paired t-test. BE were compared with Wilcoxon Signed Rank Test (ΔSGU) and paired t-test (ΔE_ab, ΔE_00, and WI_D) (α = 0.05).

The risk and the intensity of TS was statistically higher for the mandibular arch (p < 0.003). The risk and intensity of GI did not differ between arches (p > 0.38). Both arches demonstrated significant BE (ΔSGU, ΔE_ab, ΔE₀₀ and WI_D), without differences between them (p > 0.08).

In-office dental bleaching induces higher risk and the intensity of TS in the mandibular arch when compared to maxillary arch, without significant differences in gingival irritation, or bleaching efficacy.

Most patients experience tooth sensitivity regardless of the dental arch involved. However, when performing in-office dental bleaching, clinicians should consider that the mandibular arch is more likely to experience greater sensitivity compared to the maxillary arch.