This was an experimental type study with parallel controls, comparing two groups, a group with consumption of 10 minimum cigarettes per day, with a diagnosis of chronic periodontitis. And another control group were non-smokers with chronic periodontitis. For this, genomic DNA was purified from oral epithelial cells obtained by rinsing with 3% sucrose, for a single time of collection, patients received periodontal treatment after collection and data analysis. The DNA was modified by Sodium bisulfite and the methylation patterns of the DNA were analyzed with the MSPCR technique (Polymerase chain reaction). This study was approved by the Institutional Review Board of the School of Dentistry of Ribeirão Preto (CAAE:57171816.2.0000.5419 ), and all patients need to provide written informed consent.