Low Conc. H2O2 Bleaching Gel Containing Fluoride and Nano Sodium Trimetaphosphate Effective and Enamel Friendly: Study

The researchers revealed that the 17.5% hydrogen peroxide gel, enhanced with fluoride and nano-sized sodium trimetaphosphate (F/TMPnano), preserves the whitening effect while minimizing enamel demineralization, surface roughness, hydrogen peroxide diffusion, and changes in enamel morphology. The findings were published online in the Journal of Dentistry on August 29, 2024.

Alberto Carlos Botazzo Delbem, São Paulo State University - UNESP, Araçatuba, SP, Brazil, and colleagues conducted the study to assess the in vitro impact of incorporating TMPnano and sodium fluoride (F) into a 17.5% hydrogen peroxide (H2O2) bleaching gel on color change, enamel mechanical and morphological properties, and the diffusion of H2O2 through enamel and dentin.

The null hypothesis of this study is that there are no differences in the bleaching effectiveness and enamel alterations between treatments using TMPnano and sodium fluoride compared to those using the conventional bleaching agent.

The researchers assigned bovine enamel and dentin discs (n = 180) to different bleaching gel treatments: 17.5% hydrogen peroxide (17.5% HP); 17.5% hydrogen peroxide with 0.1% fluoride (HP/F); 17.5% hydrogen peroxide with 1% nano-sized sodium trimetaphosphate (HP/TMPnano); 17.5% hydrogen peroxide with 0.1% fluoride and 1% TMPnano (HP/F/TMPnano); and 35% hydrogen peroxide (35% HP). The gels were applied for 40 minutes across three sessions, each spaced one week apart.

Assessments included total color change (ΔE*ab) using the CIEDE2000 formula (ΔE00), whitening index (ΔWID), surface hardness (SH), surface roughness (Ra), cross-sectional hardness (ΔKHN), and transamelodentinal diffusion. Additionally, enamel surfaces were analyzed with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS).

The study led to the following findings:

• ΔE*ab, ΔE00, and ΔWID values were comparable among the gels that produced a bleaching effect post-treatment.
• The HP/F/TMPnano group exhibited lower mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion compared to the 17.5% HP and 35% HP groups, with the highest values.
• SEM/EDS analysis revealed surface changes in all bleached groups, though these changes were less pronounced with F/TMPnano.

Given the data and the limitations of the experimental model, the researchers concluded that incorporating fluoride and nano-sized sodium trimetaphosphate (F/TMPnano) into the 17.5% H2O2 bleaching gel significantly minimizes losses in surface and cross-sectional hardness, reduces surface roughness, limits the trans-amelodentinal diffusion of H2O2, and prevents morphological changes in the enamel. Additionally, this modification does not compromise the bleaching effectiveness of the gel.

Reference:

Nunes, G. P., Marques, M. T., De Toledo, P. T. A., Alves, R. D. O., Martins, T. P., & Delbem, A. C. B. (2024). Effect of a novel Low-Concentration Hydrogen Peroxide Bleaching Gel Containing Nano-Sized Sodium Trimetaphosphate and fluoride. Journal of Dentistry, 105330. https://doi.org/10.1016/j.jdent.2024.105330