Purpose: The purpose of this study was to investigate sleep quality and its related factors in dry-mouth patients. Subjects and Methods: A cross-sectional study was conducted in 362 patients who visited the Dry Mouth Clinic at Tsurumi University Dental Hospital with the complaint of oral dryness. Sleep quality was assessed using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J), and factors associated with the PSQI-J global score were analyzed by multiple regression. The dependent variable was the PSQI-J global score, while age, gender, resting saliva flow rate (RSFR), stimulated saliva flow rate (SSFR), VAS score of nocturnal dry mouth sensation, the presence or absence of snoring, grinding, clenching, and mouth breathing, and anxiety and depression score in the Hospital Anxiety Depression Scale (HADS) were used as the independent variables. Results: The mean PSQI-J global score was 7.9±3.9, and 232/362 (64.1%) cases were considered to be poor sleepers who showed a score of less than 5.5. The multiple regression analysis showed that anxiety (standardizing coefficient 0.330) and depression score (0.151) in HADS, nocturnal dry-mouth sensation (0.165), and age (0.209) were significantly associated with the PSQI-J global score. Conclusion: Anxiety, depression, and sleep-related xerostomia were found to be factors closely associated with the risk of disturbance of good sleep quality.
