Nitrogen-Doped Titanium Dioxide Mixed with Calcium Peroxide and Methylcellulose for Dental Bleaching under Visible Light Activation

Abstract

The available tooth whitening products in the market contain high concentrations of hydrogen peroxide (H2O2) as an active ingredient. Therefore, in order to curb the high H2O2 concentration and instability of liquid H2O2, this study evaluated the efficacy and cytotoxicity of the bleaching gel composed of 10% calcium peroxide (CaO2) and visible-light-activating nitrogen-doped titanium dioxide (N-TiO2) with methyl cellulose as a thickener. Extracted bovine teeth were discolored using coffee and black tea stain solution and were divided into two groups (n = 6). Bleaching was performed thrice on each tooth specimen in both the groups, with one minute of visible light irradiation during each bleaching time. The CIELAB L*a*b* values were measured pre- and post-bleaching. The N-TiO2 calcinated at 350 °C demonstrated a shift towards the visible light region by narrowing the band gap energy from 3.23 eV to 2.85 eV. The brightness (ΔL) and color difference (ΔE) increased as bleaching progressed each time in both the groups. ANOVA results showed that the number of bleaching significantly affected ΔE (p < 0.05). The formulated bleaching gel exhibits good biocompatibility and non-toxicity upon exposure to 3T3 cells. Our findings showed that CaO2-based bleaching gel at neutral pH could be a stable, safe, and effective substitute for tooth whitening products currently available in the market.

The effect of cetyltrimethylammonium bromide (CTAB) addition on green synthesis of porous N-doped TiO2 for photoreduction of heavy metal ion Cr(vi)

“…The crystal phase, crystal size, and crystallinity of the synthesized compounds were investigated by XRD. 29 The XRD patterns of the TiO 2 samples with the addition of nitrogen-doped CTAB are shown in Fig. 5.…”

Effects of black tea tooth staining previously to 35% hydrogen peroxide bleaching

“…Artificial dental staining is a method developed to mimic the natural intrinsic staining that occurs with the deposition of secondary and tertiary dentin along the tooth´s lifetime 3 . The protocol described in 2003 3 has been extensively used by researchers as an attempt to simulate an ideal substrate to be bleached and as an approach to standardize the teeth color of groups [24][25][26] . Nevertheless, that study 3 failed to report the pH of black tea and its effects on enamel after 24 h of immersion.…”