The article presents the results of literary sources review, namely clinical and experimental studies, meta-analyses and systematic analyzes regarding the effect of type 1 diabetes (T1D) on the periodontal tissues. According to them, the prevalence of periodontitis in patients with T1D is probably higher compared to healthy people. However, there are conflicting data on the cause-and-effect relationship between T1D and periodontitis. The article analyzes the impact of metabolic control in patients with T1D on the severity of periodontal diseases and the clinical attachment loss. Most studies show that the level of metabolic control of diabetes is associated with a high risk of developing periodontitis. The authors provide data from the analysis of the literature on possible mechanisms of periodontitis development, such as pro-inflammatory reactions and microcirculation disorders, changes in the microbial biofilm. Pathophysiological changes in bone tissue in patients with T1D, which are associated with insulin deficiency and its anabolic effect on bone tissue, worsen the biomechanical and adaptive properties of bones and may contribute to the severity of periodontitis. The conducted analysis indicates the importance of further research to assess the oral health in children with T1D.