The age-dependence of bacterial presence on oral epithelial surfaces in vivo.

Epithelial cells obtained by gentle scraping with a brush tip from the gingival margin of d 11 or 51, adjacent labial mucosa and buccal mucosa of children, adolescents and adults were stained with acridine orange and examined under a fluorescence microscope. The amount of bacteria appearing on the epithelial cells was assessed and the form of the adhered bacteria was evaluated. An age-related descending trend (negative Pearson's r in all sites) could be seen in the number of colonized cells (> 50 bacteria present) in gingival, labial and buccal areas. Adolescents and adults had significantly fewer epithelial cells with colonization of bacteria in the labial and buccal areas compared with children under 6 years. Only cocciformed bacteria were seen associated with the epithelial cells. By studying bacterial adhesion according to methods outlined in the present study, it should be possible to more closely investigate the bacteria-host relationships as they appear in nature.