Introduction: Tannerella forsythia, is an anaerobic, Gram-negative microorganism closely related to periodontal disease. Factors such as poor dental hygiene, fixed orthodontic appliances, etc. can cause dysbiosis in the bacterial community. Objective: To analyze the literature about the epidemiology, diagnostic methods, oral manifestations, relationship with systemic diseases and treatment of Tannerella forsythia in orthodontic patients. Methodology: Using the keywords "T. forsythia", "orthodontics", "oral manifestations", "diagnostics", "treatment" and "epidemiology", the main public databases were searched, with emphasis on the last 5 years. It was evaluated with the PRISMA and AMSTAR-2 guidelines. Results: At the national level, in 2019, cases of gingivitis and periodontal disease ranked fifth among the twenty main causes of diseases. As a diagnostic method, most of the studies used molecular biology (PCR) for the identification of bacterial DNA. Very few studies performed cultures for identification. T. forsythia is capable of inducing characteristic signs of gingivitis and periodontal disease. Non-surgical mechanical therapy remains the gold standard in its treatment. There are multiple diseases that can be related to the presence of T. forsythia, so its medical importance becomes more relevant and its control, essential. Conclusion: T. forsythia is closely related to periodontal disease. Its presence is mainly found in the easily accumulated plaque in patients with fixed appliances. It is essential to diagnose it for a treatment that can avoid harm to the patient.