Different light-activation systems associated with dental bleaching: a systematic review and a network meta-analysis

Clin Oral Investig. 2019 Apr;23(4):1499-1512. doi: 10.1007/s00784-019-02835-x. Epub 2019 Feb 14.


Objectives: A systematic review and a network meta-analysis were performed to answer the following research question: "Is there any light-activation protocol capable of improving color change efficacy when associated with an in-office bleaching gel in adults?"

Material and methods: A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE without date and/or language restrictions in April 23, 2017 (updated on March 30, 2018). IADR abstracts (1990-2018), unpublished and ongoing trial registries, dissertations, and theses were also searched. Only randomized clinical trials conducted in adults that included at least one group treated with in-office dental bleaching with light activation were included. The risk of bias (RoB) was evaluated using the Cochrane Collaboration tool. A random-effects Bayesian-mixed treatment comparison (MTC) model was used to combine light-activated versus light-free in-office bleaching with direct light-free comparison trials. A meta-analysis with independent analysis (high- and low-concentrate hydrogen peroxide [HP]) was conducted for color change (∆E*, ∆SGU).

Results: After the removal of duplicates, title, and abstract screening, 28 studies remained. Nine were considered to be at a low RoB, five were at a high RoB, and the remaining were at an unclear RoB. The MTC analysis showed no significant difference in color change (ΔE* and ΔSGU) between light-activation protocols and light-free in-office bleaching, regardless of the HP concentration in the efficacy of the bleaching.

Conclusion: No type of light-activated in-office bleaching was superior to light-free in-office bleaching for both high- and low-concentrate in-office bleaching gels (PROSPERO-CRD42017078743).

Clinical relevance: Although many times dental professionals use "laser whitening" as a form of marketing, this study confirmed that no type of light-activation for in-office bleaching can improve the bleaching efficacy.

Keywords: Light activation; Mixed-treatment comparison; Network meta-analysis; Tooth bleaching; Tooth discoloration.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Adult
  • Bayes Theorem
  • Dentin Sensitivity*
  • Humans
  • Hydrogen Peroxide
  • Male
  • Network Meta-Analysis
  • Tooth Bleaching Agents*
  • Tooth Bleaching*


  • Tooth Bleaching Agents
  • Hydrogen Peroxide