Effect of Smoking Cessation on Clinical and Microbiological Outcomes of the Non-surgical Periodontal Therapy

Smokers willing to quit, with 10 teeth or more, and with periodontitis (30% or more of their teeth with proximal attachment loss ≥ 5 mm) were enrolled in the study. All subjects received periodontal treatment and concurrent smoking cessation therapy. Smoking cessation therapy was performed by a team comprising physicians, nurses, a psychologist and dentists, and consisted of four 1-h counselling lectures, psychologist-assisted cognitive behavioral therapy, nicotine replacement therapy and medication (bupropion or varenicline). Smoking cessation motivation was reinforced by dentists at the maintenance sessions, by means of motivational interviewing techniques. Periodontal therapy consisted in full-mouth supra and subgingival scaling and root planing (with curettes and ultrasonic scaler); oral hygiene instruction and motivation and removal of intra-oral plaque retentive factors. Further, periodontal maintenance was performed every 3 months.

A single calibrated examiner, blinded to smoking status, assessed periodontal clinical outcomes (recession, pocket depth, clinical attachment level, plaque index and bleeding on probing). A structured questionnaire was applied in order to collect demographic and behavioral information. Expired carbon monoxide concentration was measured with a monoximeter, in order to validate smoking status. A pooled subgingival plaque sample was collected from the deepest periodontal pocket from each participant. The presence and quantification of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola were determined using real time - PCR (RT-PCR).