An inorganic salt of fluoride used topically or in municipal water fluoridation systems to prevent dental caries. Fluoride appears to bind to calcium ions in the hydroxyapatite of surface tooth enamel, preventing corrosion of tooth enamel by acids. This agent may also inhibit acid production by commensal oral bacteria. Check for "https://www.cancer.gov/about-cancer/treatment/clinical-trials/intervention/C832" active clinical trials using this agent. ("http://ncit.nci.nih.gov/ncitbrowser/ConceptReport.jsp?dictionary=NCI%20Thesaurus&code=C832" NCI Thesaurus)