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

Rosenhek, M., Macpherson, L.M.D. and Dawes, C. (1993) The effects of chewing-gum stick size and duration of chewing on salivary flow rate and sucrose and bicarbonate concentrations. Archives of Oral Biology, 38(10), pp. 885-891. (doi: 10.1016/0003-9969(93)90098-7) (PMID:8279993)

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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 °C, 21 and 36 °C after it had been chewed, and 21 °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. Ten adults chewed five test samples (a 3-g elastic band, 3 g of gum base at 21 or 36 °C, and 3 g of gum base previously chewed for 15 min and kept at 21 or 36 °C in 100% humidity) at 70 chews/min for 15 min, during which time seven saliva collections were made. Salivary flow rates showed no initial peak with the rubber band, a significantly higher initial peak with the 21 °C than with the 36 °C gum base, and smaller peaks with the previously chewed gum base at 21 and 36 °C. The flow rates after 8–10 min were not significantly different from each other. It was concluded that gum base becomes softer by the mechanical action of chewing alone, by the increase from room to oral temperature, and by uptake of saliva, and that its decrease in hardness is responsible for the decline in salivary flow rate from the initial peak.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Macpherson, Professor Lorna
Authors: Rosenhek, M., Macpherson, L.M.D., and Dawes, C.
College/School:College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Dental School
Journal Name:Archives of Oral Biology
ISSN (Online):1879-1506

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