The Open Dentistry Journal

ISSN: 1874-2106 ― Volume 14, 2020

Photobiomodulation vs. Placebo on Post-Bleaching Sensitivity and Color Change: A Split-Mouth Clinical Study

Caroline C. de Silva1, Cristiane de M. Alencar2, Brennda L. F. de Paula1, Fernanda F. de A. Jassé1, Jesuína L. N. Araújo1, Cecy M. Silva1, *
1 Department of Dental Materials, School of Dentistry, Federal University of Pará, Belém, Brazil



This study aimed to investigate the efficiency of Photobiomodulation (PBM) with low-level LASER therapy compared to placebo in post-bleaching sensitivity and color change during a three-week office bleaching treatment.


A split-mouth model was used to evaluate 21 subjects. The right and left hemi-archs were randomized to one of two groups: GP (placebo): simulated LASER application followed by tooth bleaching with 35% hydrogen peroxide; and GL: treated with PBM followed by tooth bleaching with 35% hydrogen peroxide. A four-degree modified Visual Analog Scale (VAS) was used to assess tooth sensitivity after the application of an evaporative stimulus (stimulated pain). In addition, a daily questionnaire was used to measure unstimulated pain. The color change was measured using a spectrophotometer. The Friedman and Wilcoxon tests were used to analyze data sensitivity. Color results were statistically analyzed using Analysis Of Variance (ANOVA) followed by the Tukey post-hoc test.


There was no significant difference between GP and GL for stimulated pain evaluation (p> 0.05). However, there was a significant difference between the groups for unstimulated pain evaluation (p≤ 0.05). In addition, ΔE data did not reveal any significant difference in tooth color between groups at any time (p> 0.05).


PBM prevented post-bleaching sensitivity compared to placebo, based on the daily pain assessment questionnaires. PBM did not compromise the quality of bleaching treatments.

Keywords: Tooth bleaching, Dentin sensitivity, Photobiomodulation, Low-level laser therapy, Color, Hydrogen peroxide.

Article Information

Identifiers and Pagination:

Year: 2020
Volume: 14
First Page: 267
Last Page: 274
Publisher Id: TODENTJ-14-267
DOI: 10.2174/1874210602014010267

Article History:

Received Date: 23/03/2020
Revision Received Date: 22/04/2020
Acceptance Date: 29/04/2020
Electronic publication date: 16/06/2020
Collection year: 2020

© 2020 Caldeira de Silva et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Dental Materials, School of Dentistry, Federal University of Pará, Belém, Brazil; 66075-110; E-mail:

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