Study on the Relationship between Subjective Oral Dryness and Stimulated Saliva or Oral Mucosal Moisture

Purpose: The present study aimed to investigate the relationship between subjective oral dryness and stimulated saliva or oral moisture. Methods: Twenty-one patients with subjective oral dryness (OD) and 21 healthy adults (HA) were enrolled in the study. The Saxon test was performed by chewing a gauze sponge for 2 minutes. Oral moisture was measured at the lingual mucosa (LM) and buccal mucosa (BM) by using an oral moisture checking device. Group differences in the amount of stimulated saliva and oral moisture were compared using the Mann-Whitney U test and Student’s t test. Results: The average amount of salivary secretion in OD and HA in the Saxon test was 0.65 ± 0.55 and 2.34 ± 1.41 g/2 min, respectively; the difference between the groups was significant (p < 0.01). The oral moisture at the LM in OD and HA was 27.2% ± 2.9% and 32.3% ± 1.7%, respectively; this difference was significant (p < 0.01). The oral moisture at the BM in OD and HA was 32.6% ± 2.1% and 34.0% ± 2.2%, respectively; this difference was also significant (p < 0.05). Conclusion: This study demonstrated that the amount of stimulated saliva became less than 2.00 g and the moisture at the LM became less than 30.0% in patients with subjective oral dryness. These results suggest that stimulated saliva and oral moisture are related to subjective oral dryness; thus, both the Saxon test and the test using an oral moisture checking device are useful for the assessment of subjective oral dryness.