Change in Subgingival Microbial Recolonization Following Smoking Cessation

Introduction: Smokers are at extremely high risk for chronic periodontitis, which occurs due to the presence of complex microbial communities in the subgingival crevice. Although smoking cessation is associated with clinical amelioration of periodontitis, little is known about its effect on subgingival bacterial profiles. Objectives: The purpose of this investigation was to examine shifts in recolonization of selected bacterial species among patients with chronic periodontitis following smoking cessation. Methods: 23 current smokers with generalized moderate to severe chronic periodontitis were recruited. Smoking cessation intervention and full mouth scaling and root planing were carried out. 11 subjects successfully quit for 12 consecutive months, and 12 continued smoking. Clinical data and pooled subgingival plaque samples were collected at baseline, 3,6 and 12 months from six sites with probe depths >=5mm and attachment loss >=7mm. Nested polymerase chain reaction (PCR) was used to determine the presence of 13 bacterial species including cultivated and as-yet-uncultivated organisms in these samples. Chi-square analysis with Bonferroni correction was used to determine if the prevalence of any of the species differed among the quitters and nom-quitters at each time point. Results: No differences were observed in clinical parameters between quitters and non-quitters at any time point. No differences were observed among all 13 species at baseline among quitters and non-quitters. At 3, 6 and 12 months, prevalence of Veillonella parvula was significantly lower in non-quitters than in quitters (P<0.005). Treponema denticola, Porphyromonas endodontalis and Prevotella intermedia were significantly more prevalent in smokers than quitters (P<0.005). Conclusions: The study indicates that subgingival bacterial recolonization among patients who quit smoking includes fewer putative periodontal pathogens than patients who smoke, thereby allowing for recolonization by bacteria associated with periodontal health.