The paper summarizes the results of 72 clinical studies describing the relationship of periodontal disease and diabetes mellitus and the importance of successful periodontological therapy for metabolic control of diabetes. If diabetes was considered as a single disease and a wide age bracket of patients was evaluated no relationship with periodontal disease was proved. Investigations which evaluated separately type 1 and type 2 in the middle aged population relationship with periodontal disease was detected. Investigations which evaluated separately type 1 and type 2 in the middle-agedgroup proved a more marked association with periodontal disease. Most marked was the relationship of periodontal disease in diabetes type 1 in junior as well as adult subjects. Improved diabetes control chracterized by reduction of glycated haemoglobin was found only in those investigations where periodontological therapy was supplemented by systemic antibiotic therapy.

        Key words: periodontal disease – periodontologcal treatment – diabetes mellitus – complications of diabetes – metabolic control of diabetes