Ozone is a highly reactive compound composed of three oxygen atoms that acts as an oxidant and oxidizer. It exists at the ground level as an air pollutant and a constituent of urban smog, as well as in the Earth's upper atmosphere as a protective layer from ultraviolet rays. Healthy cells contain antioxidants such as vitamins C and E to protect against ozone oxidization. However, pathogens such as bacteria contain very trace amounts of antioxidants in their membranes, which make them susceptible to ozone and destroy the cell membrane. This review explores the history, composition, and use of ozone worldwide in dentistry. Ozone therapy has thus far been utilized with wound healing, dental caries, oral lichen planus, gingivitis and periodontitis, halitosis, osteonecrosis of the jaw, post-surgical pain, plaque and biofilms, root canals, dentin hypersensitivity, temporomandibular joint disorders, and teeth whitening. The utility of ozone will undoubtedly grow if studies continue to show positive outcomes in an increasing number of dental conditions.