Inclusion Criteria:  Patients with a complete periodontal chart and full mouth radiographic series at baseline Diabetes Mellitus:Patients who consulted by an internist/endocrinologist and underwent HbA1c measurements in the last three months. Smoking status:All current smokers who had smoked more than 100 cigarettes in their lifetimes and used cigarettes for more than five years Patients meeting the case definition of periodontitis Relative radiographic bone loss(in %) was assessed on peri-apical radiograph films  Exclusion Criteria:  individuals with a systemic disease other than diabetes Smokers not reporting the number of cigarette/days or patient(s) with diabetes that do not report Hemoglobin A1c (HbA1c) test results for diabetes. individuals who do not suffer from periodontitis Patients with inaccessible files because of bad debt, destroyed record, or deceased.