Oral application of fluoride for caries prevention may tend to form calcium fluoride (CaF2) instead of the desired fluorapatite. In view of this, the transformability of CaF2 to fluorapatite has been studied. This investigation shows that CaF2 can be converted to fluorapatite in phosphate solutions at various temperatures ranging between 25 and 75°C in the pH range of 6.5 to 8.5. In the initial stage, phosphate ions, believed to be HP04=, adsorb on the particle surface. A dissolution/precipitation mechanism is proposed for the growth of fluorapatite.
Get full access to this article
View all access options for this article.
References
1.
McCann, H.G. : The Solubility of Fluorapatite and Its Relationship to that of Calcium Fluoride, Arch Oral Biol13:987-1001,1968.
Gray, J.A.; Francis, M.D.; and Griefstein, W.J. : Chemistry of Enamel Dissolution. In: Chemistry and Prevention of Dental Caries, Sognnaes, R.F., Ed., Springfield, IL: Charles C. Thomas, 1962, Chapter 5.
4.
Nelson, N.G. and Higuchi, W.I.: Mechanism of Fluoride Uptake by Hydroxyapatite from Acidic Fluoride Solutions. I. Theoretical Considerations, J Dent Res49:1541-1548, 1970 .
5.
Liang, Z.: Kinetics and Mechanism of Fluoride Uptake by Hydroxyapatite, Ann Arbor, MI: University of Michigan, Ph.D. Thesis, 1971.
6.
Zeta-Meter Manual, New York, NY: Zeta-Meter, Inc., 1961.
7.
Lucena-Conde, F. and Prat, L.: A New Reagent for the Calorimetric and Spectrophotometric Determination of Phosphorus, Arsenic and Germanium , Anal Chem Acta16: 473-479, 1957.
8.
Banerjee, D.K. ; Budke, C.C.; and Miller, F.D.: Spectrophotometric Determination of Traces of Calcium in Sodium, Anal Chem33:418-421, 1961.
9.
Badiel, C.B. and Berry, E.E.: Spectra Structure Correlations in Hydroxy and Fluorapatite, Spectrochimica Acta22: 1407-1416, 1966.
10.
Han, K.H. : Unpublished results.
11.
Matijevic, E. : The Role of Chemical Complexing in the Formation and Stability of Colloidal Dispersions. In: Colloid and Interface Science, Merker, M. et al., Eds., Vol. 1, pp. 379-395,1977.
