The association between periodontal inflammation and diabetes mellitus has been reported. The influence of hyperglycemia and gender in oral inflammation is still unclear. In this thesis, periodontal conditions (plaque index [PI], bleeding on probing [BOP], probing pocket depth [PD]), marginal bone levels on panoramic radiographs, oral yeast colonization, salivary protein concentrations and perceived oral symptoms were investigated in diabetic and control individuals. This thesis shows that radiological and clinical parameters of periodontal destruction are increased in subjects with poorly-controlled T2D, and a poor SES aggravates the periodontal conditions in these subjects. Self-perceived GB and salivary IgG/mg protein levels are higher in children with T1D compared with controls. In subjects without T2D, gutka-chewing is associated with severe periodontal conditions and oral symptoms; however, in subjects with T2D, the severity of these variables is related to glycemic levels rather than gutka consumption. Periodontal and salivary markers of inflammation, BOP and IgG/mg protein, are increased in type 2 diabetic females with C. albicans colonization compared with males.