Changes in the structural properties of the saliva with pH changes

: The pH and active concentration of sodium ions were measured by the potentiometric method and optic density and concentration of inorganic phosphorus by photoelectrocolorimetry in mixed salivary pools of 10 subjects aged 16-18 years. A cariogenic situation was simulated in these pools by slight acidification with hydrochloric acid solution, which led to structural changes. Oral fluid of subjects with negligible caries is more resistant to unfavorable effects than mixed saliva of subjects with a higher index of decayed/lost teeth. Experimental studies revealed that pH = 6.2 is the critical value of hydrogen index, at which structural properties of saliva are positively disturbed and its mineralizing potential decreases. The data contribute to elucidation of the molecular mechanisms of caries development.