Update on fluoride prophylaxis.

Fluoride is a chemical element widely distributed throughout nature. In our bodies, fluoride is considered a trace element, meaning mineral salts that, although present only in small quantities or even trace amounts, perform important biological functions. Fluoride is present in the body primarily associated with calcium, for which it has a high affinity, in teeth and bones. It is rapidly absorbed in the stomach and proximal small intestine, and peak serum levels are reached within 40-60 minutes. Fluoride absorption from water in the form of fluoride ions is faster and more complete than that bound to proteins, the form in which it is found in foods. Fluoride is excreted in urine. In children, 20% of the fluoride is eliminated, with 80-90% retained by bone tissue and developing teeth. The main benefits of fluoride are obtained through local administration, on the tooth surface. Fluoride is considered safe when consumed at recommended levels, but excessive fluoride exposure will lead to the occurrence of fluorosis [Srivastava et al., 2020] with detrimental effects on teeth, bone strength [Wei et al., 2019; Helte et al., 2021; Lindsay et al., 2023] thyroid function and cognitive development [Iamandii et al., 2023; Granjean, 2019; Taylor et al., 2025]. Efforts to develop safe and effective strategies to prevent this common disease are critical, particularly among lower-to-middleincome countries. The aim of this work is to discuss evidence that excessive fluoride exposure is not essential for caries prevention, offers little benefit to the fetus and young infant, and is particularly hazardous for young children due to the vulnerability of their developing brain.