Distribution of fluoride in human cementum.

Fluoride and phosphorus concentrations were determined in layers of cementum and dentine serially-abraded from the root surface, passing through the cementum-dentine junction and into the underlying dentine, using silicon carbide-impregnated film. The concentrations of F in the cementum mineral were variable but consistently maximal at or near to the external surface of the root and tending to fall towards the interior and across the cementum-dentine junction into the underlying dentine. The F content in the cementum tended to increase with age.