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

Hydrogen peroxide (H(2)O(2))-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 H(2)O(2)-mediated oxidative damage in the gingival tissue, and neither whether this can be detected in gingival crevicular fluid (GCF) samples. We hypothesize that H(2)O(2) whitening products may cause collateral oxidative tissue damage following in office application. Therefore, H(2)O(2) and nitric oxide (NO) levels were investigated in GCF samples obtained from patients undergoing dental bleaching with H(2)O(2) at different concentrations, in a randomized, double-blind, split-mouth clinical trial. A proteomic analysis of these samples was also performed. H(2)O(2)-based whitening products promoted inflammation which was detected in GCF samples and lasted for longer following 35% H(2)O(2) 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, H(2)O(2)-based products used in office promote inflammation irrespective of their concentration. As the inflammation caused by 35% H(2)O(2) is longer(,) patients may benefit better from using lower concentrations of this bleaching product, as they may result in less tissue damage.