Secretion of saliva by human lip mucous glands and parotid glands in response to gustatory stimuli and chewing.

To test the suggestion that minor salivary glands, such as the lower lip mucous glands, respond to stimulation in a similar manner to major glands such as the parotid, an appliance was constructed for each subject using an organopolysiloxane dental impression material which held a strip of filter paper against the inner aspect of the lower lip. The volume of labial secretion produced was determined by weight difference. Saliva from the right parotid duct was collected into pre-weighed tubes using a Lashley cannula. Test stimuli, applied for 4-min periods in triplicate, were ascorbic acid (0.08 and 0.16 M), sodium chloride (0.4 and 0.8 M) and the chewing of pieces of polyurethane foam and chicle. In 7 of 13 subjects, the response patterns of labial and parotid glands were qualitatively similar. With acid stimulation, the percentage increase in flow from the parotid was much greater than from labial glands. A significant difference was noted between the mean volumes of unstimulated secretion from the lip glands in a group of 8 subjects with restorations in lower anterior teeth and in 12 controls.