Assessment of correlation between the Modified Schirmer Test and unstimulated salivary flow testing

Purpose: To evaluate the efficacy and subjects' perception of the Modified Schirmer Test (MST) to the traditional Unstimulated Salivary Flow Test (USFT) when measuring salivary flow rate for screening and monitoring patients' dry mouth.

Methods: A total of 100 subjects were enrolled including subjects with and without dry mouth. All subjects answered a brief self-reported survey about dry mouth before and after the two types of saliva tests and their preference for the type of test administered. The order of performing MST and USFT were randomized. MST was conducted by the clinician holding a Schirmer strip paper at the bottom of the subject's mouth for 1 minute. USFT was measured by having the subject spit any accumulating saliva into a medicine cup for 5 minutes. Correlation analyses were conducted to test the relationship between MST and USFT using the Pearson correlation coefficient. All analyses were performed at a P< 0.05.

Results: A significant positive correlation existed between the two salivary flow tests (r= 0.556, P< 0.001). Most of the subjects (79%) preferred the MST while 6% preferred USFT; 15% reported no preference. A negative association between MST and USFT with age indicated that as age increased, subjects' salivary flow rate results for both types of tests decreased (r= - 0.287, P= 0.004).

Clinical significance: MST provides dental care providers with an effective, economical, easy-to-perform, and patient-preferred method to screen and monitor salivary flow rate.