Journal of Dental Research, Vol 64, 405-410, Copyright © 1985 by International & American Associations for Dental Research Online Journals
The effects of different concentrations of sucrose, fructose, and glucose on pH changes by Streptococcus mitior in an artificial mouth
F. Lagerlof, R. Dawes and C. Dawes
The aim of this study was to determine the effects of the initial sucrose
(S) concentration, as well as those of fructose (F), glucose (G), and
invert sugar (F/G), on the pH developed by a layer of S. mitior, to
represent dental plaque, in an artificial mouth which simulates the process
of oral sugar clearance. At S, F. G, and F/G concentrations of 2% and with
normal oral sugar clearance rates, the bacteria produced a smaller pH fall
from S than from the other sugars; at initial concentrations of 20%,
however, the differences were not significant. With constant S
concentrations of 0.5-35%, the minimum pH reached was 4.03 +/- 0.14 (S.D.);
with S concentrations of 50% and above, slightly but significantly higher
values (4.41 +/- 0.34) occurred. However, with normal sugar clearance, the
pH fall was much less than with a constant concentration and was dependent
on the S concentration over the range of 0-10%, but was independent at
higher concentrations. Exposure of the bacteria to S for as short a period
as two min during normal sugar clearance gave a nearly maximum pH fall.
This suggests that rinsing the mouth with water more than two min after
consumption of sucrose in liquid form will have very little effect in
reducing the pH fall in dental plaque. A more appropriate method for
reducing acid formation by dental plaque would be consumption of a salivary
stimulant which would increase the flow rate and buffer capacity of the
saliva.
