Leite FRM, et al. - The effect of tobacco smoking cessation on the risk for periodontitis vs the risk among never-smokers was assessed in this systematic review. The effect of tobacco smoking cessation on the clinical outcomes of non-surgical periodontal treatment was also determined. Via this review, the first quantitative evidence of the impact of smoking cessation on the risk for periodontitis onset and progression was gained. Smoking cessation led to a risk for periodontitis comparable to that of never-smokers, and an improvement in nonsurgical periodontal treatment outcomes. Researchers recommend dental professional considering smoking cessation interventions as a relevant component of the periodontal therapy.