Rheology of stimulated whole saliva in a typical pre-orthodontic sample population

Abstract

The dynamic viscosity (t~) of stimulated whole saliVa in a typical pre-orthodontic sample population was characterized as a function of temperature (T). Samples were collected from 30 adolescents or young adults, after screening for factors that are known to have an effect on salivary viscosity. Using a cone and plate viscometer, 1.5 ml of stimulated whole saliva was evaluated at a constant shear rate of 450s -1 from T=20°C to T= 40°C. Data from the I~-T plots showed a negative dependence of the form, p = a-bT, over a range of I~ from 1.08 to 2.45 centipoise (cps) at 34 °C. Most of the samples fell into a narrow envelope, where the mean I~ of the saliva samples ranged from 2.42+0.61 cps at 20°C to 1.57_+0.32 cps at 37°C. With regard to sample stability, viscosity-time plots indicated that a small but predictable decrease in t~ occurred during the 3 h period. The i~-Tplots generated from fresh and frozen saliva samples demonstrated an appreciable change in p as a result of refrigeration. With regard to sample reproducibility, viscometric data obtained from a typical pre-orthodontic patient over a 1-week period fluctuated within a fairly broad envelope of values.

Resistance to sliding of orthodontic appliances in the dry and wet states: Influence of archwire alloy, interbracket distance, and bracket engagement

“…Wet tests were run using fresh, wellcharacterized whole human saliva that was obtained without additional stimulation. 15,16 Operating in a closed-loop system, a peristaltic pump provided a flow rate of 3 cc/min to the archwire-bracket couple 16 via a saliva injector (not shown). All archwire and bracket materials were washed in 95% ethanol and air dried prior to testing.…”

Cavitation in Non-Newtonian Fluids

“…Typical values are η = 0.4-0.6 mPa·s for SM saliva and η = 1.8-4.9 mPa·s for SL saliva (Levine et al 1987). It is also interesting to note that saliva viscosity decreases upon storage within a few hours (Kusy and Schafer 1995). On the other hand, the high elasticity of SL saliva, in combination with appropriate adhesion to the oral mucosa, may provide a high retention of SL saliva.…”

Recombinant Expression of Aldehyde Dehydrogenase 2 (ALDH2) inEscherichia coliNissle 1917 for Oral Delivery in ALDH2-Deficient Individuals

“…The gel contains many of the same ingredients as artificial saliva, such as cellulose, glycerin, and xylitol [44] [45] [46]. The mean viscosity of saliva at room temperature is 2.1 centipoise (cP), and the mean viscosity of water at room temperature is 0.95 cP [47], [48]. We diluted the gel so that the resulting solution would be about 2 times as viscous as water, and then calculated the viscosity of our solutions by adapting the ball drop procedure from Tang (2016) [48].…”