Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 07, 2019 - November 08, 2019
Swallowing disorder has been becoming a serious issue with increasing in elderly people. Disorder sometimes appears with a decrease in saliva, because saliva has an important role in lubrication over the oral cavity and throat. Though the structure of biological mucosa has been studied physiologically, there are only few studies that examined the influence of its micro structure on fluid lubrication. Therefore, we investigated the friction characteristics by reproducing the micro structure of oral cavity and pharynx. As an example of the oral cavity mucous membrane, the tongue of a pig was subjected to observation by microscope and laser surface shape and roughness measuring machine. As a result, roughness properties of a pig tongue differed from root part to tip part, and it was confirmed that hemispherical protrusions were observed on the tip part by irregular arrangement. An imitation tongue was produced using a high-precision 3D printer. Furthermore, the concentration of thickener was determined from the measurement of the viscous characteristic by the rotational viscometer to have the same viscosity as that of saliva. It is necessary to evaluate the rheological properties of mucus with low viscosity and high spinnability like saliva, and the viscosity characteristics different from the shear viscosity. Therefore, we investigated the rheological characteristics by measuring the extensional viscosity to make a mucus that simulates saliva.We measured friction force on the imitation tongue lubricated by artificial saliva. The friction force were changed depending on the lubrication condition and the moving speed.
