Effects of Periodontitis, Smoking, and Oral Cancer on Oral Mucous Membrane Microbiotas

Objectives: To examine differences in proportions of 40 bacterial species in samples from 5 oral mucosal surfaces in systemically healthy adult subjects with and without periodontitis or a smoking habit and compare these with proportions found on the same surfaces in oral cancer subjects. Methods: Microbial samples were taken from 5 oral soft tissue surfaces in 211 systemically healthy subjects stratified by periodontal and smoking status and 21 oral cancer subjects using “buccal brushes” (Epicentre Technologies). All samples were individually evaluated for their content of 40 bacterial species using checkerboard DNA-DNA hybridization. % of total DNA probe count was determined for each species, averaged across subjects within strata, and significance of differences tested using the Mann-Whitney or Kruskal-Wallis tests. Results: When stratified for periodontal status or smoking status microbial profiles differed mildly among sample locations. Generally, periodontal pathogens were found at higher levels on the soft tissues of periodontitis subjects than on periodontally healthy subjects and at higher levels in smokers than nonsmokers. Few significant differences were found and involved 3 of the 40 species in the periodontitis subjects, and 5 species in smokers. In contrast, many significant differences were found between systemically healthy subjects and oral cancer subjects. The most striking differences included Capnocytophaga gingivalis, Prevotella melaninogenica and Streptococcus mitis. Conclusions: Proportions of bacterial species differed modestly between periodontally healthy and periodontitis subjects. Greater differences between smokers and nonsmokers were found than between periodontally healthy and periodontitis subjects, however, these were not striking. Many significant differences were seen between the systemically healthy and cancer subjects, especially in the proportions of 3 bacterial species Capnocytophaga gingivalis, Prevotella melaninogenica and Streptococcus mitis. Supported by NIDCR grant K23 DE-00453-03.