Inclusion Criteria:  Each subject must meet all of the following inclusion criteria to be enrolled in the study:  Subject must be over 18 years of age. Subject must have a BMI of higher or equal to 30 kg/ m2 Subject must have voluntarily given written informed consent.  Exclusion Criteria:  Subjects meeting any of the following exclusion criteria are not to be enrolled in the study:  Subject is currently involved in other research involving the use of antibiotics or novel or unknown medications. Self-reported pregnancy. Subject is on chronic treatment (i.e., two weeks or more) with specific medications known to affect periodontal status (phenytoin or cyclosporine) within one month of baseline visit. Subject knowingly has HIV or Viral Hepatitis. Patients are completely edentulous. Subject with uncontrolled systemic illnesses. Subject is not capable to give informed consent. Subjects on chronic antibiotic therapy (ie two weeks or more in the previous month).