The carbohydrate composition of experimental salivary pellicles.

The carbohydrate compositions of pellicles formed in vivo and others formed in vitro from submandibular, parotid, and mixed (submandibular-parotid) saliva were determined using gas-liquid chromatography. Samples of the total pellicles as well as the relatively acid-soluble supernates and acid-insoluble sediments were collected, analyzed, and compared. The differences in carbohydrates composition between the supernates and sediments, particularly in the in vivo and in vitro mixed salivary pellicles, suggest that the total pellicle is composed of more than one component. In each instance obvious differences in composition between th pellicle and the saliva from which it was formed indicated that pellicle formation is a highly selective process. Glucose:galactose ratios of approximately 1:1 were found in each of the total pellicles. These data suggest that at least one pellicle component is an unusual glycoprotein in that it contains high levels of glucose. The total submandibular salivary pellicle and both its fractions were remarkably similar in carbohydrate composition to the counterparts formed from parotid saliva alone. The data strongly suggest that there are present in both submandibular and parotid saliva similar glycoproteins that are selectively deposited onto etched enamel as the initial pellicle.