This document summarizes a study that assessed clinical parameters and salivary nitric oxide levels in smokers and non-smokers with chronic periodontitis compared to healthy individuals. It found that smokers had higher pocket depths, attachment loss, inflammatory markers, and bacterial counts compared to non-smokers. Both groups showed reductions after treatment, but gains were smaller in smokers due to effects of smoking on wound healing. Nitric oxide levels were higher in periodontitis patients and reduced after treatment in both groups.