Accessible sialic acid content of oral epithelial cells from healthy and gingivitis subjects

The purpose of the present study was to determine if there were differences in the quantity of accessible sialic acid on superficial epithelial cells collected from different areas of the mouth, and from healthy subjects with good oral hygiene, as compared to subjects with gingivitis. Superficial epithelial cells were collected by gently scraping the tongue dorsum, hard palate, free gingiva and buccal epithelium. The cells were washed and treated with clostridial neuraminidase to release accessible sialic acid; this was quantitated using a fluorometric assay. Buccal cells released an average of 62.6 ng sialic acid per 10,000 cells, which was nearly 3-fold more than cells from the hard palate (24.1 ng), free gingiva (21.9 ng), or tongue (15.4 ng). Buccal and free gingival cells collected from 5 healthy subjects had significantly higher levels of accessible sialic acid on their surface than cells collected from 5 subjects with gingivitis. These differences were significant at the p less than 0.001 and p less than 0.01 levels, respectively. The data obtained suggest that the oral hygiene status of an individual can influence the quantity of accessible sialic acid residues on oral epithelium; this would be expected to influence the attachment and colonization of bacteria which bind to sialic acid-containing receptors.