 Subjects with chronic periodontitis will undergo non-surgical periodontal treatment NSPT consisting of a complete scaling, polishing, root planning, and the irrigation of periodontal pockets with a 10 povidone iodine solution. Periodontal parameters plaque index, gingival bleeding index, pocket depth, and clinical attachment loss, insulin sensitivity using KITT, glucose tolerance using oral glucose tolerance test and serum CRP level by immunoturbidimetry will be measured before and 3 months after the NSPT. 