Background: Chronic periodontitis and Diabetes are common chronic diseases in the world. The aim of this study was to investigate the role of two biomarkers namely Homocysteine (Hcy) and Methylmalonic acid (MMA) in chronic periodontitis (CP) and type 2 diabetes mellitus (T2DM) patients and also to evaluate its correlation with serum vitamin B12 levels. Methodology: 85 adults were recruited and divided into five groups as follows:

Group 1:17 healthy individuals without CP and T2DM; Group 2: 17 subjects with CP and without T2DM; Group 3: 17 subjects
with T2DM without CP; Group 4: 17 subjects with T2DM (controlled) and CP; Group 5: 17 subjects with T2DM (uncontrolled) and CP. Plaque index (PI), Gingival index (GI), Probing pocket depth (PPD) and Clinical attachment level (CAL) were assessed. Fasting blood sugar (FBS) levels, HbA1c and Vitamin B12 levels were evaluated. Unstimulated salivary samples were collected for assessment of salivary Hcy and MMAusing ELISA. Results:The probing depth and clinical attachment level was found to be elevated in chronic periodontitis and chronic
periodontitis with diabetes mellitus patients. The levels of Hcy were found to be elevated in group 5, followed by group 4, 3, 2 and 1. Elevated levels of MMA were seen in group 5 and 4equally. A statistically significant correlation betweenparameterssuchasPI,GI,PPD,CAL,FBS,HbA1candsalivarybiomarkerswereseen(p<0.05).Anegative
correlation between Hcy, MMA and serum Vitamin B12 levels were recorded. Conclusion: Elevated levels of salivary Hcy and MMAseen in chronic periodontitis and diabetes mellitus patients, suggesting their interrelationship. The levels of homocysteine and methylmalonic acid are inversely correlated with serum vitamin B12 levels.

Keywords: Diabetes Mellitus; Chronic periodontitis; Biomarkers; Vitamin B12; Methylmalonic acid; Homocysteine