Evaluation of new compositions of 10% hydrogen peroxide‐based bleaching agents containing trimetaphosphate and fluoride on enamel demineralization

Abstract

This study evaluated the effect on enamel demineralization of 10% hydrogen peroxide (H2O2) gels containing different concentrations of sodium trimetaphosphate (TMP) and sodium fluoride (NaF) combined with the daily use of fluoridated or placebo dentifrice. Bovine enamel blocks were selected by surface hardness (n = 72) and randomly assigned to one of the following experimental treatments: 10% H2O2; 10% H2O2 + 3% TMP + 0.1% NaF; and 10% H2O2 + 0.3% TMP + 0.05% NaF, each with or without fluoridated dentifrice. H2O2‐based gels were applied for 30 min d−1 followed by treatment with dentifrice (1 min). Enamels blocks were stored in artificial saliva at 37°C between sessions during the 14 days of experiment. Percentage of surface hardness loss (%SH) was calculated, and the blocks were cut into halves to analyze cross‐sectional hardness (ΔKHN). Polarized light microscopy images were obtained of the longitudinal sections of the samples. Enamel treated with fluoridated dentifrice presented lower hardness loss than those treated with placebo dentifrice (%SH and ΔKHN). Use of TMP‐ and NaF‐based gels, regardless of concentration, led to the lowest %SH values. Specimens treated with 10% H2O2 gel had the highest %SH and ΔKHN values. Gels with 10% H2O2 + 3% TMP + 0.1% NaF showed the lowest ΔKHN values. Microscopy images clearly showed that the addition of TMP and NaF to the H2O2‐based gels was effective in reducing the loss of hardness, and the fluoridated dentifrice helped minimize it in all treatments.

Influence of bleaching gels formulated with nano-sized sodium trimetaphosphate and fluoride on the physicochemical, mechanical, and morphological properties of dental enamel

“…Among the available phosphate salts, sodium trimetaphosphate (TMP) has good adsorption on tooth enamel and bene ts such as the ability to reduce H + diffusion and facilitate calcium and phosphate diffusion [18,19] and the ability to bind to OH − groups [6,19]. Thus, micrometric TMP associated with sodium uoride (F) has been tested in bleaching gels [6,17,20], where it was possible to observe a reduction in mineral loss, diffusion, and transamelodentinal cytotoxicity of H 2 O 2 and with similar whitening e cacy of the product [6,17]. A strategy to further optimize the effect of TMP would be its use in nanoparticulate size, as shown in model studies of caries and dental erosion [18, 21,22], where the combination of TMP on the nanometer scale (TMP nano) with F provided a superior effect than the use of micrometric TMP [21,22].…”