Film‐forming properties and viscosities of saliva substitutes and human whole saliva

Abstract

Hypo-salivation, related to medical remedies, is an increasing clinical problem. Studies report a weak correlation between subjective mouth dryness and objective sialometry. This indicates that both quantity and quality of saliva are important for the surface-associated functions of saliva, such as lubrication and hydration, to be expressed. Film-forming properties and viscosities of three saliva substitutes were compared to human saliva. Adsorption to surfaces was measured by ellipsometry, infrared spectroscopy and drop-volume technique. Viscosity measurements were carried out using an oscillating rheometer. Saliva, with the lowest viscosity value and the highest protein content, presented superior film retention on both hydrophilic and hydrophobic surfaces. The carboxymethylcellulose-based MAS 84 showed intermediate values of viscosity, poorest ability to reduce surface tension, and negligible film-forming capacity. The porcine mucin-based Saliva Orthana showed about twice the viscosity of saliva and film-forming capability on preferably hydrophobic substrates. Salinum, a linseed extract, possessed the highest viscosity value and an initial surface tension close to that of saliva. The film retention on hydrophilic surfaces was not as effective as for saliva. The results indicate that the film-forming capacity of saliva substitutes is a property also to be considered in the exploration of clinically effective artificial salivas.

Effect of the vertical position of the canine on the frictional/orthodontic force ratio of Ni-Ti archwires during the levelling phase of orthodontic treatment

“…Mucin-based artificial saliva was prepared as described previously by Christersson and colleagues (18). Briefly, it was composed of porcine mucin (3.5 g), xylitol (2.0 g), methylparaben (100 mg), ethylenediaminetetra-acetic acid (50 mg), benzalkonium chloride (2.0 mg), and sodium fluoride (0.42 mg) in 100 mL of aqueous solution.…”

Tribology of o/w Emulsions Under Mouth-like Conditions: Determinants of Friction

“…11 Finally, for in-mouth lubrication, it is impossible to ignore the role of saliva. [12][13][14] Most likely, saliva proteins (e.g., the mucin glyco-proteins) adhere to surfaces and influence friction in the boundary and mixed regime by changing adhesion between the surfaces. When considering protein-stabilized emulsions, the same considerations hold for the proteins in the aqueous phase.…”

Frogs use a viscoelastic tongue and non-Newtonian saliva to catch prey

“…Our two trials with separate samples show the results are repeatable. At low shear rates _ g, the saliva zero shear viscosity m 0 plateaus at 70 Pa s, nearly 50 000 times more viscous than human saliva [15] (figure 3c). While this value may seem high, other shear-thinning biological mucus has similar values at low shear rates such as human lung mucus m ¼ 50 Pa s [16] and sundew plants m ¼ 122 Pa s [17], which also follows the Carreau-Yasuda model.…”