Viscosity and mixing properties of artificial saliva and four different mouthwashes.

Background: Numerous functions of saliva depend on its biophysical properties. Mouth rinses react with saliva and change both their own properties and properties of saliva.

Objective: The aim of this study was to define the level of mixing of artificial saliva and mouth rinses, and define their viscosity and its changes at room and body temperature.

Methods: Artificial saliva, fluoride solutions, chlorhexidine, zinc-hydroxyapatite solution and casein phosphopeptide amorphous calcium phosphate were used. To simulate their mixing, Y-channel PVC chips were used, in two different microfluidics systems. The experiments were recorded with a microscope, then the proportion of mixing was calculated using Matlab. For viscosity measurements rotational viscometer was used.

Results: The results show partial mixing of all solutions with artificial saliva. Measurements with a viscometer indicate different viscosities of all used solutions. Viscosity of a mixture of solution and artificial saliva is always in the range of viscosity of the artificial saliva and the solution separately. Moreover, viscosity of all solutions, as well as mixture with artificial saliva, significantly decreases at higher temperature.

Conclusion: Intraoral administration of mouth rinses results in change of biophysical properties of both saliva and mouth rinses. Those changes can affect preventive and therapeutic effect, and therefore oral health.