A Titanium Tetrafluoride Experimental Gel Combined with Highly Concentrated Hydrogen Peroxide as an Alternative Bleaching Agent: An In Vitro Study

Rodrigo Lins,Pedro Rosalen,Diego Silva,Vanessa Cavalli,Luís Roberto Martins,Bianca Kawabata

doi:10.3390/gels8030178

Rodrigo Lins, Pedro Rosalen + Show 4 more

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https://doi.org/10.3390/gels8030178

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Abstract

This in vitro study evaluated color change, mineral content, and morphology of enamel, pH and cytotoxicity of experimental bleaching agents containing 35% hydrogen peroxide (HP), titanium tetrafluoride (TiF), Natrosol, and Chemygel. Sixty enamel/dentin blocks were randomly treated with (n = 10) HP; HP+Natrosol+Chemygel with different TiF concentrations: 0.05 g HPT0.5, 0.1 g HPT1, 0.2 g HPT2, 0.3 g HPT3, 0.4 g HPT4. Bleaching was performed in three sessions (3 × 15 min application). Color change (CIEL-, CIEDE2000-, ) and Knoop microhardness (KHN) were evaluated. Enamel morphology and composition were observed under scanning electron microscopy and energy-dispersive spectrometry (EDS), respectively. Cell viability of keratinocyte cells was evaluated using MTT assay. Data were analyzed by one-way ANOVA and LSD and Tukey tests, and two-way repeated measures ANOVA and Bonferroni ( = 5%). The pH and EDS were analyzed descriptively. Lightness-L* increased, and a* and b* parameters decreased, except for HPT3 and HPT4 (b*). HPT0.5, HPT1, and HPT2 exhibited and similar to HP. did not present statistical difference. HP, HPT0.5, and HPT1 promoted higher KHN. HPT0.5 exhibited no changes on enamel surface. Keratinocyte cells were viable when treated with T0.5, and weak viable for T1. Experimental agents exhibited acidic pH and Ti elements. HPT0.5 exhibited bleaching efficacy, maintained KHN without enamel alterations, and did not increase cytotoxicity.

Highlights

The expressive demand for dental bleaching to improve patients’ aesthetic appearance has grown considerably over the past years [1]
In our previous study [17], an experimental gel-based formula (Natrosol with Chemygel) containing 4% TiF4 associated with a commercial 35% hydrogen peroxide (HP) agent was evaluated and we have found that this combination exhibited, in general, similar results compared with 35% HP alone
At the end of bleaching, HP exhibited no difference in a* values compared to HP, HPT0.5, HPT1, and HPT2 (p > 0.05), but higher a* values than HPT3 and HPT4 (p < 0.012)

Summary

Introduction

The expressive demand for dental bleaching to improve patients’ aesthetic appearance has grown considerably over the past years [1]. The procedure can be performed in a clinical setting with high concentrations of bleaching agents (35–40% hydrogen peroxide, HP, or carbamide peroxide, CP) under professional supervision, or at home, with low concentrations of peroxide agents (3–10% HP or 10–20% CP). Tooth color is determined by hue, value, chroma, thickness, texture, and translucency of enamel and dentin [5] These factors are modulated by either extrinsic (through contact with staining substances adhering to the tooth) or by intrinsic causes (through structural changes in the dental hard tissues composition or thickness during tooth development) [5,6]. In both cases, bleaching is effective because HP decomposes into free radicals that diffuse from enamel to dentin, and are able to oxidize complex organic molecules into smaller-sized ones, producing the whitening effect due to light reflectance difference [7–9]. Bleaching is clinically effective [2], some adverse events, such as tooth sensitivity and gingival irritation during and after bleaching procedure [2,10], structural and morphological enamel alterations [11], and mineral loss [12], are frequently observed

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