title: Structural studies on calcium fluoride formation and uptake of fluoride in surface enamel in vitro.
abstract: The structural changes in human enamel during exposure to an acetate buffer, pH 4, containing 150 parts/10(6) fluoride have been studied using scanning electron microscopy and polarized light microscopy. After exposure for 2 h the enamel surface was covered by a fine-granular layer of calcium fluoride. The underlying enamel was highly eroded with an increased pore volume in the outer layer. Following an equilibration period of 3 months the uptake of fluoride in the apatite lattice had resulted in a highly mineralized, 100-micrometer-thick surface layer rich in fluoride covering a subsurface porous zone with an unchanged fluoride content. The deeply located, caries-like porous zone may have provided calcium and phosphate for saturation of the liquid.
mesh_terms: D000085:Acetates / Q000494:pharmacology; D002021:Buffers; D002124:Calcium Fluoride / Q000378:metabolism*; D003743:Dental Enamel / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005459:Fluorides / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration
chemical_list: D000085:Acetates; D002021:Buffers; D002124:Calcium Fluoride; D005459:Fluorides