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Gingival irritation in patients submitted to at-home bleaching with different cutouts of the bleaching tray: a randomized, single-blind clinical trial

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This split-mouth randomized, single-blind clinical trial evaluated the gingival irritation (GI) of at-home bleaching with individual trays of different cutouts, as well as the tooth sensitivity (TS) and color change.

Materials and methods

One hundred and twenty patients were randomized as to which side would receive the type of bleaching tray cutout: scalloped (in the gingival margin) and nonscalloped (extended from the gingival margin). The at-home bleaching was performed for 30 min with 10% hydrogen peroxide (HP) for 2 weeks. The absolute risk and intensity of GI and TS were assessed with a visual analog scale. Color change was assessed using a digital spectrophotometer and a color guide (α = 0.05).


The proportion of patients who experienced GI was 57.5% (odds ratio 95% CI = 1.1 [0.7 to 1.8]), with no significant difference between groups (p = 0.66). The proportion of patients who experienced TS was 64.1% (odds ratio 95% CI = 1.0 [0.6 to 1.6]), with no significant difference between groups (p = 1.0). There is equivalence of scalloped and noscalloped groups for GI intensity (p < 0.01). Significant whitening was detected for both groups. Although some differences were observed between groups (CIELab and CIEDE00; p < 0.02), these were below of the considered clinically noticeable.


The different cutouts of trays proved to be equivalent when regarding gengival irritation and tooth sensitivity when 10% HP for at-home bleaching was used. Significant color change was observed in both groups. However, significant differences detected between groups are not considered clinically noticeable.

Trial registration

Brazilian Clinical Trials Registry (RBR-2s34685).

Clinical relevance

Scalloped or not, the individual trays for at-home bleaching could be considered a clinician’s decision.

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The authors would like to thank FGM Dental Group for the generous donation of the bleaching products employed in this study.


This study was partially supported by the National Council for Scientific and Technological Development (CNPq) under grants 303332/2017–4 and 308286/2019–7 and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001.

Ethical approval.

The clinical investigation was approved (4.383.682) by the scientific review committee and by the committee for the protection of human participants of the State University of Ponta Grossa and was conducted in accordance with the protocol established by the Consolidated Standards of Reporting Trials statement with extension for within-person designs. All persons gave their informed consent prior to their inclusion in the study. Details that might disclose the identity of the subjects under study were omitted. It was registered in the Brazilian Clinical Trials Registry ( under the identification number RBR-2s34685.

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Correspondence to Alessandro D. Loguercio.

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Informed consent

All persons gave their informed consent prior to their inclusion in the study. Details that might disclose the identity of the subjects under study were omitted.

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The authors declare no competing interests.

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Carneiro, T.S., Favoreto, M.W., Bernardi, L.G. et al. Gingival irritation in patients submitted to at-home bleaching with different cutouts of the bleaching tray: a randomized, single-blind clinical trial. Clin Oral Invest 26, 4381–4390 (2022).

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