The modus operandi of salivary proteins in reducing the kinetics of hydroxyapatite and enamel dissolution during simulated caries challenges is thought to be associated with interaction of glutamic acid residues with hydroxyapatite (HAp)surfaces. Polygamma glutamic acid (PGGA) is the basis of theJapanese traditional foodstuff 'Natto' and is a naturally occurring polypeptide composed of glutamic acid residues, and may therefore perform simlar caries inhibitory functions.