Fluoride profile in mature unerupted enamel following removal of surface organic material

The aim of the present study was to determine fluoride profiles in mature unerupted enamel following removal of the surface organic material. Thirty teeth were randomly allocated into three groups. The surface organic material (Nasmyth's membrane) was left intact in group I; it was removed by tooth-brushing in group II, and in group III the surface organic layer was removed along with subsurface organic material by deproteinizing. Each tooth was then sectioned into halves and a standardized biopsy area was created. Initially alkali-soluble fluoride was extracted with 1M KOH followed by acid etch analysis to measure the remaining fluoride. No difference was seen in the alkali-soluble fluoride levels but residual fluoride concentrations were significantly reduced (p < 0.05) after deproteinizing but not after toothbrushing. It would appear that a substantial amount of fluoride (approximately 25%) in mature enamel from unerupted teeth can be removed by a deproteinizing agent, which may suggest an association of this fluoride with subsurface organic material.