A screening test for unstimulated salivary flow measurement

It is well established that saliva is an important factor for the health of both soft and hard tissues in the oral cavity. This study determined: 1) the correlation between unstimulated salivary flow assessed using the Modified Schirmer tear strip Test (MST), with gravimetric and volumetric measurements and 2) the MST value that would allow the most reliable identification of patients with severe (<0.1 ml/minute) and moderate (<0.2 ml/minute) hyposalivation. A retrospective clinical study was conducted using data from 90 patients seen at the Indiana University School of Dentistry. All patients had a sample of unstimulated whole saliva collected by drooling for five minutes for volumetric/gravimetric assessment, followed by placement of the Schirmer strip in the floor of the mouth for three minutes (MST). Results showed a non-linear association between the MST and volumetric/gravimetric methods, with moderate Spearman correlation coefficients (0.67-0.71). Analysis of ROC-curves suggests that a cutoff screening value of 25 mm/three minutes provides high sensitivity (77%) and positive predictive value (71%) without significantly affecting specificity (80%). In conclusion, this study supports use of the MST test as a screening tool for hyposalivation.