Relationship between Oral Dryness and Properties of Saliva

Objectives:

Besides a decrease in the amount of saliva, and abnormality of the properties of saliva may cause oral dryness. However, the relationship between oral dryness and the properties of saliva is not clarified. The purpose of this study, therefore, was to examine the relationship between objective assessment of oral dryness and the properties of saliva.

Methods:

The subjects were 20 healthy adults (mean age 28.3±2.7 years). Eating, drinking and smoking were prohibited 30 minutes before measurements so that the effects of a meal and moisture intake could be excluded. To evaluate the oral dryness, 1) mucosal moisture (a moisture checking devise for oral mucosa, Mucus®), 2) saliva wetness (test paper ,Erusaribo®) and 3) saliva flow (unstimulated whole saliva flow rate) were measured. To evaluate the properties of saliva, 1) viscosity (capillary tube method), and 2) spinnability (a thread-forming property meter, NEVA METER®) were measured. Correlation coefficients among 3 factors of oral dryness and 2 factors of saliva properties were calculated.

Results:

A decrease in saliva flow led to high viscosity (R=-0.73, P<0.05). A rise of viscosity led to high spinnability (R=0.64, P<0.05). High spinnability led to a decrease in saliva wetness (R=-0.45, P<0.05). There was no other significant correlation in other combinations.

Conclusion:

This study clearly shows that oral dryness and the properties of saliva are mutually related, which may indicate that abnormality of the properties of saliva is one of the cause of oral dryness.