Uptake of fluoride by human surface enamel from ammonium bifluoride and consequent reduction in the penetration in vitro by caries-like lesions.
In-vitro fluoride uptake by mid-coronal, premolar enamel surfaces from topically-applied solutions of NH4HF2 was determined using a multi-electrode system for fluoride and calcium analyses. In tooth surfaces dehydrated with 100 per cent ethanol before the topical application of 1 per cent aqueous NH4HF2, there was a 2-3-fold increase in fluoride concentration up to a depth of 50 microns and fluoride enhancement to a total depth of 100 microns into the enamel. Caries-like lesions were induced in vitro in both treated and untreated enamel by the use of acidified, 6 per cent hydroxymethyl-cellulose gel containing 0.04 per cent hydroxyapatite at pH 4.5. After 120 days exposure, the mean depth of lesion penetration in the controls was 149 (+/- 34) microns. No lesions occurred in half the treated specimens; in specimens with lesions, the mean depth of penetration was 19 (+/- 3) microns. Thus, NH4HF2 was a potent inhibitor of caries-like lesion formation in vitro.
D000134:Acid Etching, Dental; D064751:Ammonium Compounds; D001641:Bicuspid; D002327:Cariostatic Agents / Q000378:metabolism; D003731:Dental Caries / Q000517:prevention & control; D003743:Dental Enamel / Q000378:metabolism*; D005459:Fluorides / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D000644:Quaternary Ammonium Compounds
D064751:Ammonium Compounds; D002327:Cariostatic Agents; D000644:Quaternary Ammonium Compounds; C024822:ammonium fluoride; D005459:Fluorides