[The determination of the coagulation threshold of the electrolyte potassium chloride in human mixed saliva].

For quantitative assessment of the stability of dispersed phase corpuscles in the gingival fluid, coagulation threshold and coagulating effect of electrolyte KCl were studied in salivary pools of caries-resistant (CR) and caries-liable (CL) subjects by the optic method widely used for investigation of pure colloid systems. Test samples were prepared by mixing certain volumes of saliva, distilled water, and KCl. Light absorbance was measured by photoelectrocolorimetry on a MKMF-1 device and pH was measured by the potentiometric method using pH-121 device. Coagulation threshold and coagulating effect of the electrolyte were estimated using the graphic method. The saliva of both CR and CL subjects generally follows the regularities typical of pure colloid systems. KCl coagulation threshold of CR subjects' saliva is higher than of subjects with caries, while its coagulating effect is higher in the CL group. Dispersed phase corpuscles in the saliva of CR subjects are more stable than in subjects with caries. These results may be used in development of quantitative methods for assessing the stability of salivary dispersed phase corpuscles and salivary mineralizing capacity in subjects with different oral status.