Relationship Between Oral Dryness and Wetness of Tongue Dorsum

Objectives: A recently developed scale membrane filter strip wetness tester was used for measuring oral mucosal moisture in an investigation of the relationship between oral mucosal wetness and sense of oral dryness in Japanese adults.

Subjects and methods: Six hundred twenty Japanese adults (aged 20-99 years old), who were patients of dental clinics or hospital dental departments, or hospitalized with general diseases, were enlisted as subjects and given a questionnaire regarding xerostomia. Then the subjects were divided into 3 groups, dry mouth, mild dry mouth, and wet mouth, on the basis of the their subjective sense of oral dryness. Measurement of tongue dorsum moisture was carried out using the new wetness tester and clinical diagnosis of dry mouth was performed using a clinical classification scale of tongue mucosa wetness (grade range, 0-3 ).

Results: The average moisture value in the tongue dorsum was 1.6±2.1 mm in the dry mouth group, 3.0±3.0 mm in the mild dry mouth group, and 3.9±3.6 mm in the wet mouth group, and 4.0±2.9 mm when the clinical diagnosis of dry mouth grade was grade 0, 2.4±2.4 mm when it was grade 1, 1.8±2.3 mm when it was grade 2, and 0.7±1.5 mm when it was grade 3 (values shown as mean ± SD). The subjects whose value of tongue dorsum moisture was less than 1mm indicated a high value of clinical classification scale significantly (p<0.01). The results of the wetness tester were positively correlated with the sense of dry mouth (p<0.01) and clinical diagnosis grade (p<0.01).

Conclusions: Our results suggest that this new wetness tester is able to evaluate oral dryness and may also be applicable for the diagnosis of dry mouth in older or disabled persons.