Introduction: Periodontal disease impacts up to 50% of the population worldwide. Tannerella forsythia is a gram-negative anaerobic bacterium, which is part of the red complex that triggers periodontal disease.

Objective: To evaluate T. forsythia in relation to its epidemiology, diagnosis, treatment and oral manifestations, as well as its periodontal and systemic role.

Methodology: A search for information was carried out in databases such as PubMed, Scopus and Google Scholar, using logical operators AND, OR and NOT. We searched for the mention of T. forsythia bacteria related to the keywords: epidemiology, oral manifestations, diagnosis, and treatment.

Results: T. forsythia bacteria are present in the oral cavity, increasing their colonization in periodontal disease and endodontic lesions, as well as in cardiovascular and systemic diseases. Diagnosis can be made by molecular tests such as PCR and ELISA, or by clinical findings. Its treatment consists of the first two phases of periodontal treatment, hygienic and, if necessary, corrective for its elimination and regulation of colonization. In the oral cavity it can develop clinical attachment loss, bleeding on probing and increase in pocket depth, as well as loss in bone crest levels.

Conclusions: The knowledge of this bacterium as well as its effects are of high impact on the supporting tissues. Its control is the key to a successful periodontal treatment.