RESUMEN
INTRODUCTION: The bidirectional relationship between diabetes mellitus and periodontal disease has been reported in the literature, suggesting that poor glycemic control is strongly associated with increased risk of developing periodontal disease. Therefore, this systematic review evaluated the level of knowledge of this bidirectional relationship among patients with diabetes. METHODS: This systematic review (protocol CRD42018117902) was conducted according to PRISMA guidelines. The following databases were considered: Medline/PubMed, Scopus, and Web of Science. Search strategy (April 05th , 2021) considered proper combination of keywords and eligibility criteria. The quality of studies was evaluated using the Appraisal tool for Cross-Sectional Studies (AXIS). RESULTS: Among the 328 records identified in the initial search, 24 studies were selected, considering a total of 8,693 patients. All studies used a cross-sectional design. Among the included studies, only five showed prevalence of knowledge higher than 50%, ranging from 5.8% to 75.9%. Interestingly, 58.0% of patients reported that they brush their teeth at least 1x/day, but only four studies reported that the dentist was the main source of information. In terms of methodology and result quality, just one study clearly showed all information evaluated by the AXIS tool. Most of studies did not report sample size calculations and did not used validated questionnaires to assess patient knowledge. CONCLUSION: The results show that less than half of people with diabetes have knowledge about their increased risk for periodontal disease, and often the dentist is not the main source of information to motivate them.