The effects of fluoride on the gastric mucosa of the rat.

Fluoride is widely used for the prevention of dental caries. Very low concentrations of fluoride are routinely ingested in optimally fluoridated drinking water of many communities. Higher concentrations of fluoride in toothpastes, mouthrinses and topically applied gels also may be ingested, especially by children. The potential effect of ingested fluoride on the gastric mucosa was the subject of this investigation. Solutions of 0, 1, or 10 mM NaF in 0.1 N HCl were placed in rat stomachs in vivo for up to one hour. The effects of fluoride on the structure and function of the gastric mucosa were determined. Histologic and SEM examinations revealed dose- and time-dependent damage to the surface mucous cells. The 10 mM, but not the 1 mM, NaF solution increased gastric mucosal permeability to small but not to large molecules.