Journal of Dental Research, Vol 68, 786-790, Copyright © 1989 by International & American Associations for Dental Research Online Journals
The effect of daily gum-chewing on salivary flow rates in man
G. N. Jenkins and W. M. Edgar
Department of Oral Biology, Dental School, University of Newcastle, England.
Following reports of increased salivary gland size and increased function,
induced by increased mastication in animals, the effects of long-term,
frequent gum-chewing on resting and stimulated flow rates were studied in
human volunteers in separate experiments in Newcastle upon Tyne and in
Toronto. In both experiments, unstimulated and stimulated saliva flow rates
were measured in student volunteers at intervals of one or two weeks over a
baseline period. Approximately half of the subjects were then given
sugarless gum to be chewed (four pieces per day) over the experimental
period; controls refrained from vigorous mastication. During (and, in
Newcastle, after) the experimental period, salivary flow rates were
measured at intervals, as before. In Newcastle unstimulated, but not
stimulated, flow rates increased in the gum-chewing group and were still
elevated (compared with controls) eight weeks following the experiment. In
Toronto, the mean results showed no effect of gum-chewing, but the seven
gum-chewers among the 11 subjects with low baseline flow rates (less than
0.3 mL/min) showed a 43% rise in unstimulated flow rate (p approximately
0.05). The results suggest that increased mastication, in the form of
gum-chewing, can increase unstimulated flow rates, especially in those with
low salivary function. In addition to short-term beneficial effects of
sugarless gum, these long-term effects indicate the possibility of a
beneficial effect in caries prevention.
