The effects of chewing-gum stick size and duration of chewing on salivary flow rate and sucrose and bicarbonate concentrations.

The objectives were to determine (1) the relations between salivary flow rate and the sample weights of chewing-gum and gum base, (2) whether any reduction in salivary flow rate with duration of chewing is due to a reduction in hardness of gum base with chewing, and (3) the sucrose and bicarbonate concentrations in saliva elicited by different weights of chewing-gum containing sucrose. Ten subjects chewed, for 20 min, samples of 1, 2, 3, 6 and 9 g of gum base and of a sucrose-containing chewing-gum. With each sample, salivary flow rates peaked initially and then fell to a relatively constant value. Flow rates during the periods of 1-2 and 15-20 min were linearly related to the logarithm of sample weight. With the chewing-gum samples, virtually all the sucrose was released into the saliva during the 20 min of chewing, with peak concentrations (201-666 mM) at 1-2 min, and bicarbonate concentrations were higher with the 9-g than the 3-g samples. Six subjects chewed 3 g of gum base and within 45 min the weight of base had increased to 122% of the original, presumably due to the uptake of saliva. The hardness of gum base was determined at 21 and 36 degrees C, 21 and 36 degrees C after it had been chewed, and 21 degrees C after it had been chewed without exposure to saliva, and gave Brinell values of 0.277, 0.038, 0.022, 0.002 and 0.061, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)