Related Experiment Video
Updated: Jul 5, 2026

Ratiometric Imaging of Extracellular pH in Dental Biofilms
Published on: March 9, 2016
Relationship between quantitative assessments of salivary buffering capacity and ion activity product for
H Aiuchi1, Y Kitasako, Y Fukuda
1Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. aiuchi.ope@tmd.ac.jp
Background:
The ion activity product for hydroxyapatite (Ip(HA)) is a comprehensive parameter reflecting pH, calcium and phosphate ion concentration in saliva which govern the degree of saturation with respect to the dissolving tooth mineral. The aim of this study was to evaluate the relationship between quantitative assessments of salivary buffering capacity and Ip(HA) in relation to cariogenic potential.
Methods:
Stimulated whole saliva was collected from 33 patients, and the initial pH of samples was measured using a hand-held pH meter. Then samples were titrated with 0.1 N HCl to evaluate buffering capacities and divided into three groups (high, medium and low). After measuring concentrations of calcium and phosphate ions in the samples, Ip(HA) was calculated using the values of the ion concentrations and pH. Differences in the mean pH values, the concentrations of calcium, phosphate ions and log[Ip(HA)] among three groups were analysed using the Kruskal Wallis and the Mann-Whitney non-parametric test, p < 0.05.
Results:
After HCl 50 microL titration, there were statistical differences of the mean pH and Ip(HA) among each buffering capacity group. Moreover, after 50 microL HCl titration, there was an excellent correlation between the buffer capacity and log[Ip(HA)].
Conclusions:
The pH change for saliva after HCl titration has a significant influence on the rate of Ip(HA).
More Related Videos
Related Concept Videos
Buffers
Polyprotic Acids
Buffers: Buffer Capacity
In the graph, pH is plotted as a function of the number of moles of base (Cb) added to a weak acid...
Calculating pH Changes in a Buffer Solution
Bicarbonate-Carbonic Acid Buffer
Factors Affecting Solubility

