Smoking and microbiological diversity in patients with generalized chronic periodontitis.
OBJECTIVE: To determine the bacterial diversity in the subgingival biofilm of smokers and non-smokers with generalized chronic periodontitis by using culture-independent molecular methods based on 16S ribosomal DNA cloning.
METHODS: Non-smokers and smokers (n=20) presenting, at least, nine teeth with probing pocket depth (PPD) (≥5mm), bleeding on probing (BOP), no history of periodontal treatment in the last 6 months were selected, and subgingival biofilm samples were collected. DNA was extracted and the 16S rRNA gene was amplified with the universal primer pairs 27F and 1492R. Amplified genes were cloned, sequenced, and identified by comparison with known 16S rRNA sequences.
RESULTS: A total of 840 clones were sequenced. Seventy-two species were identified in smokers, whereas 78 were identified in non-smokers. The most detected phylotype harboring smokers was Tannerella forsythia (9 patients), and the genera Fusobacterium sp. presented a higher prevalence of detected species, being detected 11 different species of this genera. In non-smokers, Filifactor alocis were detected in 100% and 9 different phylotypes of Synergistetes sp. and 11 of Treponema sp. were identified in those periodontal pockets. Thirty-nine phylotypes were exclusively detected in non-smokers while 40 phylotypes were detected only in subgingival biofilm collected from smokers. Data analysis additionally showed that the same percentage of periodontal sites (30%) from smokers and non-smokers concomitantly presented the three species of Socransky's red complex (Porphyromonas gingivalis, Treponema denticola, Tannerela forsythia), whereas the classical putative periodontal pathogen, Aggregatibacter actinomycetemcomitans, was not detected in any sample regardless of smoking status.
CONCLUSION: Within the limits of this study, we conclude that there are microbiological dissimilarities between smokers and non-smokers with generalized chronic periodontitis, and that this information might provide important insights for achieving a more predictable and stable treatment outcome in smokers.