Abstract
The present study was carried out by focusing attention on the viscosity of human saliva, one of its physical characterisics, in an effort to predict possible caries susceptibility and its activities as well. Previous studies dealing with salivary viscosity were chiefly limited to those which employed the capillary viscometer but for the present purpose it was thought to he more effective to use a cone and plate viscometer for the measurement of the rheological character of saliva, which is a non-Newtonian fluid.
Although there are occasionally found studies using a cone and plate viscometer, they deal either with some kind of sliding test or with a comparison by mean of graphs and, for this reason, they are rather complicated and are far from being practical.
In the present study, therefore, attempts were made to introduce the Casson yield value as well as T. I., which are widely used in the industrial field, so that the characteristics of salivary viscosity might be better understood and assessed.
To determine wheter these two methods would prove to be effective indices for better designation of salivary viscosity, data of the seeming viscosity (C. P. ) in 4 sliding tests were comparatively analyzed and were studied in terms of 4 aspects such as the differences by days, difference between the sexs and individual differences.
As for subjects, use was made of healthy adults,10 males and 10 females each, who were subjected to 6 measurements over a period of 3 days between 10 and 11in the morning and 2 and 3 in the afternoon.
