This book presents fluoride as a key preventive and therapeutic agent in dentistry. It is a controversial issue, although very robust scientific evidence supports that the appropriate use of fluoride can help strengthen enamel and reduce the risk of dental caries with a minimal risk of dental fluorosis. With its ability to promote remineralization and protect against cavities, fluoride plays a vital role in maintaining long-term oral health, reducing the prevalence of cavities in communities and reducing the burden of caries in an individual. It can be safely delivered through various methods, such as toothpaste, mouth rinses, professional varnishes, or water fluoridation, making it accessible and effective for populations worldwide.