Multicomponent evaluations of the oxidising actions and status of a peroxoborate-containing tooth-whitening system in whole human saliva using high resolution proton NMR spectroscopy

High resolution H-1 nuclear magnetic resonance (NMR) spectroscopy was emplo yed to conduct a multicomponent investigation of the oxidation of salivary biomolecules by peroxoborate present in a tooth-whitening dentifrice formul ation. The results acquired demonstrated that peroxoborate gave rise to the oxidative decarboxylation of the hydrogen peroxide scavenger pyruvate, a r eaction generating acetate and CO2 as products. Experiments performed on ch emical model systems confirmed the oxidative consumption of pyruvate by den tifrice-derived peroxoborate, and also revealed that the salivary electron donors cysteine and methionine (precursors to volatile sulphur compounds), were oxidised to cystine and methionine sulphoxide respectively. The bioche mical and periodontal significance of these results is discussed. (C) 1999 Elsevier Science Inc. All rights reserved.