Characterization of remineralising phosphate in the oral environment

Abstract

Phosphorus, along with calcium, is essential for remineralisation in the oral environment. Phosphate ions, in particular, can act as a natural buffer to neutralize acids and counter the dissolution process. Further, saliva plays a crucial role against demineralization. Despite the numerous phosphate-rich remineralising products available on the market and in professional products, the speciation of phosphate in the oral environment remains poorly addressed in dental research. Solution-state 31P NMR spectroscopy was used to characterize the dissolved state of soluble or less soluble phosphates, including phosphate glasses, in the oral environment. Additionally, the potential of the enzymatic hydrolysis of the soluble phosphate chains by alkaline phosphatase enzyme in solution was preliminary explored. The results indicate that various types of soluble phosphates exhibited different 31P NMR spectra. The signals observed in the 31P NMR spectra fall into three distinct regions. The chemical shifts of 31P NMR spectra were affected by the pH. Enzymatic hydrolysis of condensed phosphate groups in solution by alkaline phosphatase was found to occur. The findings could be used to design new phosphate containing materials that would be expected to dissolve in the oral cavity.