The utility of oral moisture measurement for the diagnosis of Sjögren’s syndrome: Its potential application as a diagnostic criterion

Objectives To investigate the use of an oral moisture meter to aid in the diagnosis of Sjögren’s syndrome (SS) by measuring the moisture values and salivary flow rate (SFR) simultaneously. Methods The SFR and moisture values of the dorsum of the tongue and buccal mucosa were measured in 40 patients with SS and 29 healthy controls using an oral moisture meter. In addition, a visual analogue scale (VAS) was used to determine the degree of subjective oral symptoms (xerostomia, decreased saliva production, drinking during eating, oral pain, dysphagia, and dysgeusia). Results The moisture values of the dorsum of the tongue and buccal mucosa were significantly lower in SS patients than in healthy subjects (both p<0.01). SFR, especially when measured by the spitting test, correlated positively with the moisture values of the dorsum of the tongue (p<0.0001) and buccal mucosa (p<0.0003). Furthermore, the sensitivity, specificity, and accuracy of the oral moisture meter measurements of the dorsum of the tongue and buccal mucosa were 92.5%, 68.9%, and 82.6%, and 70.0%, 82.8%, and 73.9%, respectively. The moisture values of the dorsum of the tongue had a moderate negative correlation with the VAS scores of secondary subjective oral symptoms of xerostomia (oral pain, dysphagia, and dysgeusia), whereas a weak negative correlation was observed for subjective oral symptoms directly related to xerostomia (xerostomia and decreased saliva production). Conclusions The oral moisture meter accurately reflected the results of the SFR tests and chronic subjective oral symptoms, and therefore might be a diagnostic criterion for SS.