Fluoride in Toothpaste Linked to Dental Fluorosis in Children
The human tooth enamel is one of the hardest surfaces in nature, consisting of 95% inorganic materials. Despite its strength, tooth enamel can be attacked by acids, bacteria, and environmental chemicals, according to a study published in the American Journal of Pathology. To protect tooth enamel from acids, most toothpaste contains fluoride, which promotes mineralization of the enamel and reduces its susceptibility to acids. However, excessive fluoride intake during tooth development can cause dental fluorosis, a condition that affects about a quarter of children in industrialized countries. Dental fluorosis results in white discoloration, rough surfaces, and under-mineralized areas of the teeth, which persist into adulthood because tooth enamel does not repair or regenerate.
Researchers at New York University investigated the cellular mechanisms that cause dental fluorosis. Using cultures of ameloblasts, the cells that produce tooth enamel, the researchers exposed the cells to high doses of sodium fluoride to observe the effects. They found that fluoride disrupts the calcium balance in the cells, leading to reduced calcium deposits and mineralization of the enamel. Fluoride also damages the mitochondria, the energy suppliers of the cells, and increases cellular stress. The study showed that only sodium fluoride, not sodium chloride or sodium bromide, causes calcium imbalance and enamel mineralization problems. The researchers concluded that fluoride is the cause of dental fluorosis.
Francisco Aulestia, the lead author of the study published in Science Signaling, emphasized the importance of understanding the cellular mechanisms behind dental fluorosis, given its prevalence and the limited knowledge about it. Rodrigo Lacruz, a co-author of the study, said that the observations provide insight into how dental fluorosis develops. The study highlights the need to balance the benefits of fluoride in toothpaste with the risk of dental fluorosis, especially in children whose teeth are still developing.
