Saddleback Journal of Biology - Saddleback College

Fall 2009 Biology 3B Paper
The peak pH of bicarbonate-stimulated saliva was
greater than that produced by chewing the standard
gum at all times. It represents a decrease in the
hydrogen ion concentration of the whole mouth saliva,
thus yields greater pH value. The salivary bicarbonate
concentration is known to increase with increasing
flow rate (Dawes 1969). The bicarbonate concentration
of gum-stimulated saliva has been reported to increase
from an unstimulated value around 4mM to a peak of
15mM when chewing a 3 gram gum sample
(Rosenhack, et al, 1993). It is because the rise in
salivary pH there was an increase in salivary
bicarbonate concentrations. The bicarbonate gum
pellets contain 3 percent sodium bicarbonate, and it is
most likely that the additional increase in salivary pH
with the bicarbonate gum was due to bicarbonate ions
leaching out from the gum. As this reservoir diminishes
with time, the differences in pH of the saliva stimulated
by each gum will decreases. The rate at which gum
ingredients enter the saliva has been estimated by
measuring the salivary sucrose levels in participants
chewing sucrose-containing gum (Rosenhack, et.al.,
1993). It was found that most of the sucrose was lost
over 10-15minutes, depending on the size of the
sample (Rosenhack, et.al., 1993). These data are not
consistent with the time course of the salivary pH
changes induced by chewing bicarbonate gum in the
present experiment (Fig.1). This study presents new
findings that the bicarbonate chewing gum delayed the
loss of bicarbonate by approximately 10 minutes, over
20-25 minute interval. The higher salivary pH achieved
with chewing bicarbonate gum, compared to a
standard, sugar-free gum, may have important oral
health implications.
Acknowledgements
The authors wish to thank Professor Steve Teh of the
Biological Sciences Department, Saddleback College
for his technical assistance and devotion to the success
of this investigation. Also thank all the volunteers who
donated their precious saliva. Special thanks goes to
Dr. Tran, D.D.S. for his suggestion on conducting this
investigation.
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Saddleback Journal of Biology
Spring 2010