[Saliva and saliva substitutes].

Saliva is a mixture of secretions of both the large salivary glands (glandula sublingualis submandibularis and parotis) and the minor salivary glands of the palate, tongue, lips and cheeks. The rheological flow of the separate glandular salivas differs remarkably. Sublingual saliva is both more viscous and elastic than the other glandular salivas. The viscosity of parotid saliva, which is of importance during eating (digestion), is equal to the viscosity of water. Utilization of the combination of viscosity and elasticity may improve new saliva substitutes and of frequent applications of saliva substitutes by xerostomia patients may reduce. Besides, the utilization of correct visco-elastic properties of saliva substitutes may lead to better moistening and protective properties.