Salivary Gland Hypofunction

Xerostomia is not a reliable indicator of salivary hypofunction. To measure the salivary flow rate in a stimulated state, you can use a parasympathomimetic drug such as pilocarpine. Sensory stimuli such as swallowing, mastication, smell, sight or thought results in an increase in salivary flow from 0.3 cc/minute to >1 cc/minute and the magnitude of salivary response is also directly related to a subject’s sense of hunger.21

Clinical signs of hyposalivation include: the presence of new or recurrent dental caries on root surfaces or incisal edges, sticky mucosal surfaces, absence of expressible saliva from the major salivary ducts, and an absence of pooled saliva in the floor of the mouth.23

To measure the unstimulated flow rate of saliva, ask the patient to empty saliva from his/her mouth into a graduated tube or preweighed container for ten minutes. The patient needs to be seated in a forward leaning position. If salivary flow is <1.0 ml/10 min., the patient is at significant risk for dental caries.23