Journal of Dental Research, Vol 63, 906-909, Copyright © 1984 by International & American Associations for Dental Research Online Journals
An in vitro method for making repeated pH measurements on human dental plaque
B. G. Bibby and A. Krobicka
A combination pH micro-electrode inserted into human plaque centrifuged to
the base of a closely-fitting fine-mesh wire "basket" has been used to make
continuous recordings of the pH responses produced by exposure to various
carbohydrate substrates. The pH depressions given by continued immersion in
sugar and starch solutions resemble, both in depth and duration, those
obtained by telemetric pH measurements of approximal plaque samples. In
contrast, brief exposure to sugar solutions will produce a Stephan type of
pH curve. Measurements of pH can be made using a succession of different
substrates if, after each substrate is tested, the electrode-plaque
assembly is washed with water and its acidity neutralized in circulating
saliva. It is suggested that this in vitro pH method could be used instead
of the telemetric measurements of approximal plaque for comparing acid
production from foods or for other purposes.
