Rheological parameters of saliva in comparison with taste examination

Abstract

BACKGROUND: It is generally unknown if taste sensitivity is dependent upon saliva viscosity. The rheological properties of saliva result from many factors and it has been shown to behave as a non-Newtonian fluid whose viscosity decreases with increasing shear rate. Taste sensitivity may be quantitatively assayed by electro-gustometry. OBJECTIVES: The aim of this work was to compare saliva rheological properties, obtained with a rotary-oscillating rheometer, to quantitative measures of taste sensitivity, using electro-gustometry. METHODS: Saliva samples were taken from 27 healthy non-smoking donors – 7 men and 20 women aged 18–65 years (mean age – 37 years). After thresholds of taste sensation were measured, the saliva samples were taken and characterized in terms of their rheological properties and pH. Saliva viscosity was measured in the order of decreasing shear rate in the range 100–0.01 s−1. Viscoelastic properties were examined under constant frequency oscillations (with f = 0.5 Hz) and with decreasing shear effective amplitude [Formula: see text]. RESULTS and CONCLUSIONS: Saliva viscosity was found to decrease with increasing shear rate and varied with time. Analysis of the dependence of the viscosity values of saliva and components of complex viscosity did not show a significant correlation with taste sensation. A dependency of taste sensation on pH could not be discerned due to the narrow range of naturally occurring pH.

Artificial Saliva for Therapeutic Management of Xerostomia

“…The sticky consistency of the normal saliva shows that it is a nonNewtonian fluid. [ 5 ] When the flow rate is in the range of 0.1–1 liter/s, residual saliva's sticky consistency is much greater than the sticky consistency during chewing and talking when the shown rate is about 60 and 160 liter/s. This reliance of density on the rate of alteration is called pseudoplasticity and is essential for its normal functioning.…”