Detection and Quantification of Periodontal Pathogens in Smokers and Never‐Smokers With Chronic Periodontitis by Real‐Time Polymerase Chain Reaction

Background: The purpose of the present investigation is to compare the presence and number of periodontal pathogens in the subgingival microbiota of smokers versus never‐smokers with chronic periodontitis and matched probing depths (PDs) using real‐time polymerase chain reaction (RT‐PCR). Methods: Forty current smokers and 40 never‐smokers, matched for age, sex, and mean PD of sampling site, were included in this investigation. A full‐mouth periodontal examination was performed, and a pooled subgingival plaque sample was collected from the deepest site in each quadrant of each participant. To confirm smoking status, expired carbon monoxide (CO) concentrations were measured with a CO monitor. The presence and quantification of Aggregatibacter actinomycetemcomitans , Porphyromonas gingivalis, Tannerella forsythia , and Treponema denticola were determined using RT‐PCR. Results: Smokers had greater overall mean PD ( P = 0.001) and attachment loss ( P = 0.006) and fewer bleeding on probing sites ( P = 0.001). An association was observed between smoking status and the presence of A. actinomycetemcomitans ( P <0.001). The counts of A. actinomycetemcomitans ( P <0.001), P. gingivalis ( P = 0.042), and T. forsythia ( P <0.001) were significantly higher in smokers. Conclusions: Smokers showed significantly greater amounts of P. gingivalis , A. actinomycetemcomitans , and T. forsythia than never‐smokers. There was a significant association between smoking and the presence of A. actinomycetemcomitans.