Study of saliva secretion and the salivary fluoride concentration of the human minor labial glands by a new method.

Unstimulated and stimulated flow rate from minor lower labial glands and the fluoride concentration of resting whole and labial saliva were measured over 15 min using a novel method avoiding eversion of the lips. Resting salivary flow rate was measured as 1.09+/-0.44 microl/min/cm2 and stimulated flow rate as 3.13+/-1.05 microl/min/cm2. Secretion rates were significantly (p<0.001) increased during periods of continuous speaking. The increase in secretion elicited by labial movements and speaking may result from mechanical stimulation and/or activity of myoepithelial cells. Fluoride concentrations in resting whole saliva and in unstimulated minor labial gland saliva were 0.066+/-0.048 and 0.181+/-0.073 parts/10(6), respectively. The secretory capacity of the minor labial glands and the high F concentration in their secretions suggests a significant contribution to the F content of whole saliva. Our non-invasive method permits collection from the minor labial glands of a volume large enough for chemical analysis. It should prove useful for studying the effects of different secretory stimuli.