Periodontal diseases became widespread in the XX—XXI centuries. Almost 95% of the world's population is over 35 years old and 80% of children suffer from periodontal diseases of varying severity, while inflammatory periodontal diseases occur in 90-95% of cases. Periodontitis is a disease that causes damage to periodontal tissues, including gums, cement, and alveolar bone. This can be caused by various factors, including a violation of oral hygiene, smoking, genetic factors, and other causes. To date, scientists are trying to develop new methods and tools to effectively combat periodontitis. One of the innovative directions that make it possible to create an effective drug is the inclusion of selenium in the composition of drugs. Selenium is one of the trace elements necessary for the normal functioning of the human body. In recent years, it has been discovered that selenium plays an important role in dentistry: it is antioxidant properties, antimicrobial and anti-inflammatory properties open up new possibilities for use in dental practice. Nevertheless, both excess and lack of selenium can be extremely dangerous for the human body. This review article discusses the prospects for the use of selenium in dentistry, in particular in the treatment of periodontitis. In addition, the consequences of incorrect selenium dosages for the human body are described in detail.