Electron microscopic studies of human mixed saliva.

With foam components removed, mixed saliva from three donors were solidified in liquid nitrogen and sectioned, mounted, and fixed. Examination by transmission (TEM) and scanning (SEM) electron microscopy and energy-dispersive X-ray (EDAX) analysis were performed for paraformaldehyde-fixed sections, some of which were OsO4-postfixed. The TEM and certain SEM examinations showed the presence of fine and dense salivary network structures, seemingly originating from the major fibrous components. In OsO4-treated sections, TEM pictures showed reticulated arrangements with open cellular diameters down to 0.2 microns. The EDAX analyses particularly showed the presence of Ca, Fe, K, P, and S, with increased Ca readings in major components. Untreated sections showed that strands, with diameters of more than 1-2 microns, had more electron-dense central portions than peripheries and sometimes had interior, very electron-dense, granules. The observed features indicate that saliva has internal structures consistent with its colloid chemical characteristics.