Relationship between salivary flow rate and clinical symptoms and behaviours in patients with dry mouth.

The purpose of this study was to investigate the relationship between whole salivary flow rate and dry mouth-related subjective symptoms and behaviours in patients with dry mouth. Seventy-eight patients (13 men and 65 women, 58.2 +/- 13.5 years) with dry mouth were asked a standardized series of questions concerning dry mouth-related symptoms and behaviours. Whole salivary flow rates were measured under unstimulated and stimulated conditions. The effect of oral dryness on daily life was significantly associated with the flow rate of stimulated whole saliva (r(s) = -0.30, P < 0.01) and frequency of oral dryness (r(s) = 0.46, P < 0.01). Dry mouth-related symptoms and behaviours were significantly associated with the whole salivary flow rate and the correlation was more remarkable with respect to stimulated whole saliva. The most common dry mouth-associated complaint was sensation of burning mouth. The effect of oral dryness on daily life was significantly affected by the presence of taste disturbances. Collectively, dry mouth-related symptoms and behaviours were significantly associated with whole salivary flow rate. Moreover, the severity of dry mouth-related symptoms was more closely correlated with the flow rate of stimulated saliva, compared with the unstimulated flow rate.