Smoking and subgingival microflora in periodontal disease

Aim: The present investigation was undertaken to analyze the influence of smoking on the periodontal disease associated subgingival microflora. The population included 33 smokers and 31 non-smokers in the age range 36-86 years. Methods: Microbial samples were obtained from 4 sites per patient. The checkerboard DNA-DNA hybridization technology was used for detection of the bacterial species P. gingivalis, P. intermedia, P. nigrescens, B. forsythus, A. actinomycetemcomitans, F. nucleatum T. denticola, P. micros, C. rectus, E. corrodens, S. noxia and S. intermedius. Results: Using score 1 as cutoff, contrasting colonized versus non-colonized patients, 8 out of 12 species were detected in greater than or equal to 90% of both smokers and nonsmokers. Using score 4 as cutoff, contrasting heavily colonized patients versus non-colonized and less heavily colonized patients, the detection rates decreased in both smokers and non-smokers. No significant differences in detection rates were observed between smokers and non-smokers. Logistic regression analysis indicated that neither smoking, probing depth nor gingival bleeding influenced the occurrence of the species analyzed. The lack of a smoking exposure dose-response further supported the indication of a limited influence of smoking. Conclusion: Smoking exerts little, if any, influence on the subgingival occurrence of several of the bacteria most commonly associated with periodontal disease.