Journal of Dental Research, Vol 64, 1065-1068, Copyright © 1985 by International & American Associations for Dental Research Online Journals
Enamel microhardness change and plaque pH measurements in an intra-oral model in humans
M. E. Essig, W. R. Bodden, E. L. Bradley Jr, T. Koulourides and T. Housch
Changes in plaque pH and microhardness of bovine enamel slabs were
evaluated with a seven-day intra-oral cariogenicity test (ICT). The test
enamel slabs were mounted in prosthetic appliances with a Dacron mesh cover
for enhancement of microbial colonization. Three percent solutions of
sucrose, sorbitol, and xylitol were evaluated as four daily extra-oral
immersions of 10 min each, for seven days, and the results were compared
with baseline experiments (no daily immersions). The pH was measured with
antimony electrodes on one-day and seven-day ICT plaque samples that were
challenged with a one-minute immersion in the studied substrates. Plaque
samples in the baseline experiments were challenged with 3% sucrose. The
enamel softening was assessed with measurements of microhardness. Sucrose
challenge caused pH depression with both the baseline and the
sucrose-immersed plaque. Sorbitol and xylitol challenge did not depress the
plaque pH. Compared with the baseline, sucrose immersions caused enamel
softening; sorbitol and xylitol did not.
