 Eligible participants were 32 adult patients treated for chronic periodontitis and participating in a supportive periodontal therapy program at the Department of Periodontology of the Dental Clinic of the Islamic Azad University, Dental Branch of Tehran were included in the current study; Recruitment of participants started july 2014 and ended may 2015. The study met the criteria of the Helsinki Declaration of 1975, revised in 2008. The survey plan was reviewed and sanctioned, approved by the ethics commission of the Institutional Ethical Committee and Review Board of the Deputy of Research, School of Dentistry. All subjects received the oral and written explanation of the intent of the survey and signed an informed consent after receiving detailed information about the purpose, the benefits, and the possible risks associated with the trial. Individuals satisfying the following entry criteria were recruited: 