[Comparative study of the rheological properties of artificial saliva types based on hydroxy-propyl-methyl-cellulose (methocel) and carboxy-methyl-cellulose (CMC)].

Apparent viscosity at different shear rates was measured for two types of saliva substitutes based on methocel and CMC, and was compared with that of human whole saliva. Results indicate, that fresh mixed human saliva is viscoelastic, exhibiting pseudoplasticity. Methocel containing artificial saliva and human whole saliva are similar in their rheological properties, while the preparation based on CMC is almost a Newtonian liquid. From the results it can be concluded that the saliva substitute containing 0.5% of methocel appears to be a better substitute for natural saliva than of containing CMC as far as rheological properties are concerned.