High-Resolution ¹H NMR Investigations of the Oxidative Consumption of Salivary Biomolecules by a Tooth-Whitening Formulation: Relevance to Safety Issues

Wyman Chan, Ryan Banks, Edward Lynch, Martin Grootveld

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DOI: 10.4236/aces.2012.21008                

Abstract

A multicomponent evaluation of the oxidative consumption of salivary biomolecules by a hydrogen peroxide (H₂O₂)-containing tooth-whitening formulation has been performed using high-resolution proton (1H) nuclear magnetic resonance (NMR) spectroscopy. Unstimulated human saliva samples (n = 10) were treated with aliquots of supernatants derived from 1) the H₂O₂-containing whitening gel, 2) the corresponding tooth-whitening accelerant solution containing an amino-alcohol activator, and 3) a combination of these product agents pre-mixed in the recommended manner. 600 MHz 1H NMR spectra acquired on these samples demonstrated that H₂O₂ present in the whitening gel gave rise to the oxidative decarboxylation of salivary pyruvate (to acetate and CO₂), the direct oxidation of trimethylamine and methionine (to trimethylamine-N-oxide and methionine sulphoxide respectively), and the indirect oxidative consumption of lactate and carbohydrates in general. Experiments conducted on a chemical model system confirmed the consumption of pyruvate by added H₂O₂, and also revealed that this method could be employed for determinations of the H₂O₂ content of tooth-whitening products. In conclusion, high-resolution ¹H NMR analysis provides much valuable molecular information regarding the fate of tooth-whitening oxidants in human saliva, and also permits an assessment of the ability of endogenous antioxidants therein to protect against any soft tissue damage arising from the possible leakage of H₂O₂ from tooth-whitening application trays.

Keywords

Biomedical ¹H NMR Analysis; Human Saliva; Tooth-Whitening Product; Hydrogen Peroxide; Salivary Antioxidants

Conflicts of Interest

The authors declare no conflicts of interest.

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