Diabetes mellitus is a group of physiological impairment characterized by hyperglycaemia resulting from defect in insulin secretion, insulin action or both.This disease can lead to many complications in various regions of the body, the oral complications that can be seen are xerostomia, dental caries, gingivitis, periodontal disease, increased tendency to oral infections etc. Periodontal disease is the only 6th complication of diabetes mellitus.1,2 In summer 2021, the covid-19 second wave in India has raised more consequential concerns about the ability of this infection to trigger the glucogenic machinery in Covid patients, possibly leading to the new onset of diabetes mellitus. The purpose of this review is to summarizes the chairside diagnosis of Diabetes mellitus and its oral aspects by a periodontist specially in post Covid era.