Physiological Factors Affecting Salivary Flow Rate, Oral Sugar Clearance, and the Sensation of Dry Mouth in Man

Abstract

This paper discusses methods for collection of both whole saliva and individual gland secretions, the normal ranges of salivary flow rate, the effects of physiological variables which influence flow rate, and the role of saliva in oral sugar clearance. The physiological basis for the sensation of dry mouth is discussed, and a new concept is advanced which states that the sensation of dry mouth will occur when the salivary flow rate is less than the sum of the rates of water absorption and evaporation from the mouth. In a study of the effects of anticholinergic agents on salivary flow, the subjects experienced the sensation of dry mouth when the normal flow rate of unstimulated saliva was reduced by from 40 to 50%.

Stimulated Salivary Flow Rate in Chronic Hemodialysis Patients

“…Determining the stimulated salivary flow rate provides information about the secretory capacities of salivary glands, but the method used for collecting stimulated saliva is important [30]. Kho et al [14]used gustatory stimulation with citric acid which is quite potent, but must be renewed frequently thus causing an interrupted flow rate.…”

“…Kho et al [14]used gustatory stimulation with citric acid which is quite potent, but must be renewed frequently thus causing an interrupted flow rate. On the other hand, mechanical stimulation with inert material, as paraffin wax used in our study, provides a constant rate of salivary flow [30, 31]. Another factor affecting the salivary flow rate is the body posture, being supine as Kao et al [29]preferred, decreases the flow rate so all of our subjects were required to be seated during the procedure [30, 31].…”

“…On the other hand, mechanical stimulation with inert material, as paraffin wax used in our study, provides a constant rate of salivary flow [30, 31]. Another factor affecting the salivary flow rate is the body posture, being supine as Kao et al [29]preferred, decreases the flow rate so all of our subjects were required to be seated during the procedure [30, 31]. To minimize the effect of biological rhythms and body fluid, stimulated saliva collection time and temperature were standardized during the study [16, 31].…”

“…As in healthy subjects, age and gender were unimportant factors affecting the salivary flow rate in HD patients [30]. No significant correlation could be established between the stimulated salivary flow rate and the duration of HD treatment.…”

Study on the Clinical Significance and Related Factors of Thirst and Xerostomia in Maintenance Hemodialysis Patients

“…All subjects were instructed to refrain from smoking, eating, drinking or tooth brushing at least 1h prior to saliva collection. UWS was collected for 5 min using an established spitting technique [19,20]. In the crossover trial, UWS and paraffin chewing-stimulated whole saliva (PC-SWS) were both collected before analysis.…”