Direct cannulation of the parotid duct was performed in 11 children (ages 6 to 15 years) with cystic fibrosis, and resting and reflex salivary flow and ionic composition measured. Two to three months later, the studies were repeated on the same 11 subjects. Results showed that (1) the values obtained were similar to those found in previous studies, and (2) data on nonstimulated salivas from those whose ducts were cannulated on two occasions displayed significant differences in flow of saliva, sodium concentration, and chloride concentration.
Fritz ME, Caplan DB, Leever D, Levitt J. Composition of Parotid Saliva on Different Days in Patients With Cystic Fibrosis. Am J Dis Child. 1972;123(2):116-117. doi:10.1001/archpedi.1972.02110080094006