Type I diabetes mellitus (T1DM) is a chronic metabolic disease caused by the body's failure to produce insulin. The resulting hyperglycemic state causes chronic systemic inflammation that is harmful to health. Periodontal disease (PD) is a chronic inflammatory disease whose etiology is multifactorial. The relationship between these diseases has shown that PD potentiates the chronic inflammation that occurs during diabetes. In this project, we intend to follow up on the first national study of the prevalence of PD in T1DM patients in Portugal. In the previous project, we began with the description of the predominant medical and social parameters obtained by the medical history and periodontal status. We also investigated the specific profile of the inflammatory response, leaving it to be determined the oral microbiome in diabetic patients diagnosed with PD and without PD, taking into account that the etiology of periodontal disease is related to the specific presence of oral bacteria. A deeper understanding of the bidirectional relationship between PD and diabetes will contribute decisively to the determination of
new treatment strategies and guide future lines of research.