Hydrogen peroxide-based products alter inflammatory and tissue damage-related proteins in the gingival crevicular fluid of healthy volunteers: a randomized trial

Abstract

Hydrogen peroxide (H₂O₂)-based products are effective in tooth whitening; however, their safety is controversial as they may harm patient tissues/cells. These effects are suggested to be concentration-dependent; nonetheless, to date, there are no reports on H₂O₂-mediated oxidative damage in the gingival tissue, and neither whether this can be detected in gingival crevicular fluid (GCF) samples. We hypothesize that H₂O₂ whitening products may cause collateral oxidative tissue damage following in office application. Therefore, H₂O₂ and nitric oxide (NO) levels were investigated in GCF samples obtained from patients undergoing dental bleaching with H₂O₂ at different concentrations, in a randomized, double-blind, split-mouth clinical trial. A proteomic analysis of these samples was also performed. H₂O₂-based whitening products promoted inflammation which was detected in GCF samples and lasted for longer following 35% H₂O₂ bleaching. This included time-dependent changes in NO levels and in the abundance of proteins associated with NO synthesis, oxidative stress, neutrophil regulation, nucleic acid damage, cell survival and/or tissue regeneration. Overall, H₂O₂-based products used in office promote inflammation irrespective of their concentration. As the inflammation caused by 35% H₂O₂ is longer_, patients may benefit better from using lower concentrations of this bleaching product, as they may result in less tissue damage.

Figure 1

Analysis of gingival crevicular fluid markers in patients undergoing a 2-session tooth whitening with products containing hydrogen peroxide (H₂O₂, 15–35%). Nitric oxide end-product (${\mathrm{NO}}_{\mathrm{x}}^{-}$ = ${\mathrm{NO}}_2^{-}$ + ${\mathrm{NO}}_3^{-}$) concentrations (panel A), H₂O₂ concentrations (panel B) and myeloperoxidase (MPO) contents (panel C) were measured in gingival crevicular fluid samples collected before (baseline) and at different time-points after dental bleaching. *p < 0.05 vs. the corresponding baseline values.

Figure 2

Time-dependent abundance of proteins detected in gingival crevicular fluid samples obtained from patients undergoing a 2-session tooth whitening with hydrogen peroxide (H₂O₂, 15%). Proteins were classified by biological function as associated with: NO synthesis, oxidative stress, neutrophil regulation, nucleic acid damage, cell survival and tissue regeneration. Samples were collected before (baseline) and at different time-points after dental bleaching.

Figure 3

Time-dependent abundance of proteins detected in gingival crevicular fluid samples obtained from patients undergoing a 2-session tooth whitening with hydrogen peroxide (H₂O₂, 35%). Proteins were classified by biological function as associated with: NO synthesis, oxidative stress, neutrophil regulation, nucleic acid damage, cell survival and tissue regeneration. Samples were collected before (baseline) and at different time-points after dental bleaching.