Why is the pH of ASTRINGEDENT X the same as the pH of regular ASTRINGEDENT even though the percent acidity and content of ferric sulfate is higher?
The pH of Astringedent is 1.31.6 and the pH of Astringedent X is 1.21.4. Percent acidity or acid number is a relative number for comparing levels of acidity, e.g. a chemical with a percent acidity of 20 would require two times as much known base to neutralize it as would a chemical with a percent acidity of 10. There is a correlation of this number to pH, however in most cases, it is an indirect correlation. For example, the pH of 40% phosphoric acid is close to zero and its percent acidity is close to 90. The pH of 20% phosphoric acid is still approximately zero, yet its percent acidity would be 1/2 that of the 40%. The acid number is meaningful from a physiological standpoint, providing clinicians with a relative number that allows them to get a feel for how quickly a low pH chemical should be buffered and neutralized by body fluids, etc. Acid and base effects on tissues are related not only to concentrations but also the length of time they are active on tissues. The
