Fluoride is classified as a mineral, but it is not found as such in nature. Fluorides are found in the soil, water, plants, animals, and air. Its existence is necessary to maintain proper oral health. During the formation of the teeth it contributes improving the apatite of the dental enamel, but its excess leads to an alteration at different levels, which is known as dental fluorosis, causing an injury to the dental structure, weakness of the teeth and dental caries affecting the smile aesthetics, therefore, this review is carried out in order to deepen the knowledge of the action of fluoride in dental enamel and the result of its inadequate administration in our body.