Desorption of acquired enamel pellicle in vivo by pyrophosphate

Soluble pyrophosphate (PP) has been introduced in dentifrices to inhibit the formation of dental calculus. The mechanism of inhibition is probably an adsorption of the pyrophosphate ions to the Ca-sites on the enamel surfaces and a blocking of the active sites for crystal growth. It has been shown in a recently published study that PP reduced the protein adsorption to hydroxyapatite (HA) in vitro and also inhibited the pellicle formation in vivo. The aim of the present study was to examine the desorption potential of pyrophosphate on the acquired enamel pellicle in vivo. Enamel fragments were carried in the mouth to collect pellicle material and some of the enamel surfaces were then treated with PP. Pellicle formation was examined by SEM of the enamel surfaces. The results showed that pyrophosphate desorbed the acquired enamel pellicle effectively. The clinical consequences of this effect is unknown, but it could possibly explain some aspects of hypersensitivity of teeth observed in some individuals using dentifrices containing PP.