The mechanistic action of fluoride on inhibition of enamel demineralization was investigated using 19F magic angle spinning nuclear magnetic resonance (MAS-NMR). The aim of this study was to monitor the fluoride-mineral phase formed on the enamel as a function of the concentration of fluoride ions [F-] in the demineralizing medium. The secondary aim was to investigate fluorapatite formation on enamel in the mechanism of fluoride anti-caries efficacy. Enamel blocks were immersed into demineralization solutions of 0.1 M acetic acid (pH 4) with increasing concentrations of fluoride up to 2,262 ppm. At and below 45 ppm [F-] in the solution, 19F MAS-NMR showed fluoride-substituted apatite formation, and above 45 ppm, calcium fluoride (CaF2) formed in increasing proportions. Further increases in [F-] caused no further reduction in demineralization, but increased the proportion of CaF2 formed. Additionally, the combined effect of strontium and fluoride on enamel demineralization was also investigated using 19F MAS-NMR. The presence of 43 ppm [Sr2+] in addition to 45 ppm [F-] increases the fraction of fluoride-substituted apatite, but delays formation of CaF2 when compared to the demineralization of enamel in fluoride-only solution.

1.
Brauer DS, Karpukhina N, Law RV, Hill RG: Structure of fluoride-containing bioactive glasses. J Mater Chem 2009;19:5629-5636.
2.
Christoffersen J, Christoffersen MR, Kibalczyc W, Perdok WG: Kinetics of dissolution and growth of calcium fluoride and effects of phosphate. Acta Odontol Scand 1988;46:325-336.
3.
Ekstrand J: Fluoride in plaque fluid and saliva after NaF or MFP rinses. Eur J Oral Sci 1997;105:478-484.
4.
Featherstone JDB: Prevention and reversal of dental caries: role of low level fluoride. Community Dent Oral Epidemiol 1999;27:31-40.
5.
Featherstone JDB, Shields CP, Khademazad B, Oldershaw MD: Acid reactivity of carbonated apatites with strontium and fluoride substitutions. J Dent Res 1983;62:1049-1053.
6.
Fischer C, Lussi A, Hotz P: The cariostatic mechanisms of action of fluorides. A review. Schweiz Monatsschr Zahnmed 1995;105:311-317.
7.
Fox JL, Iyer BV, Higuchi WI, Hefferren JJ: Solution activity product (KFAP) and simultaneous demineralization-remineralization in bovine tooth enamel and hydroxyapatite pellets. J Pharm Sci 1983;72:1252-1255.
8.
Ganss C, Schlueter N, Klimek J: Retention of KOH-soluble fluoride on enamel and dentine under erosive conditions - a comparison of in vitro and in situ results. Arch Oral Biol 2007;52:9-14.
9.
Koulourides T, Keller SE, Manson-Hing L, Lilley V: Enhancement of fluoride effectiveness by experimental cariogenic priming of human enamel. Caries Res 1980;14:32-39.
10.
Larsen MJ, Jensen SJ: Experiments on the initiation of calcium fluoride formation with reference to the solubility of dental enamel and brushite. Arch Oral Biol 1994;39:23-27.
11.
Lynch RJM, Mony U, ten Cate JM: The effect of fluoride at plaque fluid concentrations on enamel de- and remineralisation at low pH. Caries Res 2006;40:522-529.
12.
Mitra SB, Oxman JD, Falsafi A, Ton TT: Fluoride release and recharge behavior of a nano-filled resin-modified glass ionomer compared with that of other fluoride releasing materials. Am J Dent 2011;24:372-378.
13.
Moreno EC, Kresak M, Zahradnik RT: Fluoridated hydroxyapatite solubility and caries formation. Nature 1974;247:64-65.
14.
Newbrun E: What we know and do not know about fluoride. J Public Health Dent 2010;70:227-233.
15.
Ogaard B: CaF2 formation: cariostatic properties and factors of enhancing the effect. Caries Res 2001;35(suppl 1):40-44.
16.
Ogaard B, Rølla G, Helgeland K: Uptake and retention of alkali-soluble and alkali-insoluble fluoride in sound enamel in vivo after mouthrinses with 0.05% or 0.2% NaF. Caries Res 1983;17:520-524.
17.
Preston AJ, Mair LH, Agalamanyi EA, Higham SM: Fluoride release from aesthetic dental materials. J Oral Rehabil 1999;26:123-129.
18.
Ripa LW: A critique of topical fluoride methods (dentifrices, mouthrinses, operator-applied, and self-applied gels) in an era of decreased caries and increased fluorosis prevalence. Public Health Dent 1991;51:23-41.
19.
Rølla G, Ogaard B, Cruz Rde A: Topical application of fluorides on teeth. New concepts of mechanisms of interaction. J Clin Periodontol 1993;20:105-108.
20.
Rølla G, Saxegaard E: Critical evaluation of the composition and use of topical fluorides, with emphasis on the role of calcium fluoride in caries inhibition. J Dent Res 1990;69:780-785.
21.
Saxegaard E, Rölla G: Fluoride acquisition on and in human enamel during topical application in vitro. Scand J Dent Res 1988;96:523-535.
22.
Takagi S, Liao H, Chow LC: Effect of tooth-bound fluoride on enamel demineralization/remineralization in vitro. Caries Res 2000;34:281-288.
23.
Tavss EA, Bonta CY, Joziak MT, Fisher SW, Campbell SK: High-potency sodium fluoride: a literature review. Compend Contin Educ Dent 1997;18:31-36.
24.
ten Cate JM: Review on fluoride, with special emphasis on calcium fluoride mechanisms in caries prevention. Eur J Oral Sci 1997;105:461-465.
25.
ten Cate JM, Featherstone JDB: Mechanistic aspects of the interactions between fluoride and dental enamel. Crit Rev Oral Biol Med 1991;2:283-296.
26.
ten Cate JM, van Duinen RN: Hypermineralization of dentinal lesions adjacent to glass-ionomer cement restorations. J Dent Res 1995;74:1266-1271.
27.
Thuy TT, Nakagaki H, Kato K, Hung PA, Inukai J, Tsuboi S, Nakagaki H, Hirose MN, Igarashi S, Robinson C: Effect of strontium in combination with fluoride on enamel remineralization in vitro. Arch Oral Biol 2008;53:1017-1022.
28.
Vogel GL, Mao Y, Chow LC, Proskin HM: Fluoride in plaque fluid, plaque, and saliva measured for 2 hours after a sodium fluoride monofluorophosphate rinse. Caries Res 2000a;34:404-411.
29.
Vogel GL, Tenuta LMA, Schumacher GE, Chow LC: No calcium-fluoride-like deposits detected in plaque shortly after a sodium fluoride mouthrinse. Caries Res 2010;44:108-115.
30.
Vogel GL, Zhang Z, Chow LC, Carey CM, Schumacher GE, Banting DW: Effect in vitro acidification on plaque fluid composition with and without a NaF or a controlled-release fluoride rinse. J Dent Res 2000b;79:983-990.
31.
White DJ, Bowman WD, Faller RV, Mobley MJ, Wolfgang RA, Yesinowski JP: 19F MAS-NMR and solution chemical characterization of the reactions of fluoride with hydroxyapatite and powdered enamel. Acta Odontol Scand 1988;46:375-389.
32.
White DJ, Nelson DG, Faller RV: Mode of action of fluoride: application of new techniques and test methods to the examination of the mechanism of action of topical fluoride. Adv Dent Res 1994;8:166-174.
33.
Yesinowski JP, Mobley MJ: F-19 MAS-NMR of fluoridated hydroxyapatite surfaces. J Am Chem Soc 1983;105:6191-6193.
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