A quantitative study of fluoride distribution profile changes in dental enamel was conducted by means of electron probe micro-analysis (EPMA). Fluoride-deposited hydraxyapatite powders were chosen as fluoride standards, and analytical conditions were optimized. The lower limit of detection for fluoride was estimated to be 270 ppm, with an accelerating voltage of 5 kV, a specimen current of 40 nA, and a counting time of 40 seconds. Fluoride profiles in fluoride-treated dental enamel, which exhibited intact surface layers and subsurface demineralization, were determined. The results were also compared with those of an acid-abrasion method, and reasonable consistency was found between these two methods, although the acid-abrasion procedure yielded a slightly lower fluoride content in the initial layers, followed by a higher content of fluoride in the deeper layers. The precision of fluoride profile data obtained from EPMA permits further studies to be conducted on the kinetics of subsurface demineralization and intact surface layer formation ("white spot" formation) which is observed during the acid challenge of dental enamel.
Get full access to this article
View all access options for this article.
References
1.
Andersen, C.A. (1967): Methods of Biochemical Analysis, Vol. XV, D. Glick, Ed., New York : Wiley, pp. 147-270.
2.
Baud, C.A. and Bang, S. (1970): Electron Probe and X-ray Diffraction Microanalysis of Human Enamel Treated in vitro by Fluoride Solution, Caries Res4:1-13.
3.
Bergstrom, D.H.; Fox, J.L.; and Higuchi, W.I. (1984): Quantitative Microradiography for Studying Dental Enamel Demineralization and Remineralization, J Pharm Sci73:650-652.
4.
Berkovitz, B.K.B. and Heap, P.F. (1976): The Effect of Fluoride on Iron, Calcium and Phosphorus Distribution in the Rat Incisor, Caries Res10:337-351.
5.
Clarkson, B.H.; Wefel, J.S.; Miller, I.; and Edie, J. (1984): Microprobe and SEM Analysis of Surface Coatings on Caries-like Lesions in Enamel after Metal Ion Mordanting and APF Application , J Dent Res63:106-110.
Daculsi, G. and Kerebel, L.M. (1980): Ultrastructural Study and Comparative Analysis of Fluoride Content of Enameloid in Sea-water and Fresh-water Sharks, Arch Oral Biol25:145-151.
8.
Darling, A.I. (1956): Studies on the Early Lesion of Enamel Caries with Transmitted Light, Polarized Light and Radiography, Br Dent J101:289-297, 329-341.
9.
Edie, J.W. and Glick, P.L. (1979): Irradiation Effects in the Electron Microprobe Quantitation of Mineralized Tissues, J Microscopy117:285-296.
10.
Fox, J.L. (1977): Diffusion Controlled Processes in Complex Chemical Systems, Ph.D. Thesis, University of Michigan, Ann Arbor, MI.
11.
Freund, F. and Knobel, R.M. (1977): Distribution of Fluoride in Hydroxyapatite Studies by Infrared Spectroscopy, J Chem Soc (Dalton)11 :1136-1140.
12.
Gee, A.; Domingues, L.; and Deitz, V. (1954): Determination of Inorganic Constituents in Sugar , Anal Chem26:1487-1492.
13.
Hals, E. and Selvig, K.A. (1977): Correlated Electron Probe Microanalysis and Microradiography of Carious and Normal Dental Cementum, Caries Res11:62-75.
14.
Iyer, B.V.; Fox, J.L.; Higuchi, W.I.; Hefferren, J.J.; and Vishnupad, K.S. (1983): A New Acid Abrasion Procedure for Studying F Profiles in Demineralized/Remineralized Bovine Tooth Enamel, Caries Res17:297-303.
15.
Jenkins, R. and De Vries, J.L. (1978): Worked Examples in X-ray Analysis, 2nd ed., London: Macmillan Press Limited.
16.
Jenkins, R.; Gould, R.W.; and Gedcke, D. (1981): Quantitative X-ray Spectrometry, New York: Marcel Dekker, Inc.
17.
Larsson, S.J.; Lodding, A.; Odelius, H.; and Film, G.J. (1977): Application of SIMS: Study of Fluoride in Dental Enamel, Adv Mass Spec7:797-803.
18.
Lodding A.; Gourgout, J.M.; Petersson, L.G.; and Frostell, G. (1974): Aspects of Quantitative Determination by Ion Probe of Fluorine Concentrations in Apatites, Z Natiirforsch29:897-900.
19.
Mobley, M.J. and Yesinowski, J.P. (1983): The Fluoride-Hydroxyapatite Reaction Studies by 19F Magic-angle Spinning NMR, J Dent Res62:301, Abst. No. 1184.
20.
Shearer, T.R.; Kolstad, D.L.; and Suttie, J.W. (1978): Electron Probe Microanalysis of Fluorotic Bovine Teeth, Am J Vet Res39:1393-1398.
21.
Stineman, R.W. (1980): A Consistently Well-Behaved Method of Interpolation , Creative Computing6:54-57.
22.
Takuma, S.; Ogiwara, H.; and Suzuki, H. (1975): Electron-Probe and Electron Microscope Studies of Carious Dentinal Lesions with a Remineralized Surface Layer, Caries Res9:278-285.
23.
Tveit, A.B. and Lindh, U. (1980): Fluoride Uptake in Enamel and Dentin Surfaces Exposed to a Fluoride-containing Amalgam in vitro: A Proton Microprobe Analysis , Acta Odontol Scand38 :279-283.
24.
Tveit, A.B.; Totdal, B.; Klinge, B.; Nilveus, R.; and Selvig, K.A. (1985): Fluoride Uptake by Dentin Surfaces Following Topical Application of TiF4, NaF and Fluoride Varnishes in vivo, Caries Res19:240-247.
25.
Uchtmann, H. and Duschner, H. (1982): Electron Spectroscopic Studies of Interactions between Superficially Applied Fluorides and Surface Enamel, J Dent Res61:423-428.
26.
Wei, S.H.Y. (1971): Dynamics of Enamel Surface Chemistry-Electron Microprobe Analysis. In: Chemistry and Physiology of Enamel Symposium, University of Michigan School of Dentistry and the Dental Research Institute, September 17-18, pp. 43-58.
27.
Wei, S.H.Y. and Forbes, W.C. (1974): Electron Microprobe Investigations of Stannous Fluoride Reactions with Enamel Surfaces, J Dent Res53:51-56.
28.
West, V.C. and Malcolm, A.S. (1977): An Electron Microprobe Analysis of Osteofluorosis in the Rabbit, Calcif Tissue Res22 :285-296.
29.
Wu, M.S.; Higuchi, W.I.; Fox, J.L.; and Friedman, M. (1976): Kinetics and Mechanism of Hydroxyapatite Crystal Dissolution in Weak Acid Buffers Using the Rotating Disk Method, J Dent Res55:496-505.
30.
Yonese, M.; Fox, J.L.; Nambu, N.; Hefferren, J.J.; and Higuchi, W.I. (1981): Fluoride Remineralization of Demineralized Bovine Tooth Enamel and Hydroxyapatite Pellets, J Pharm Sci70:904-907.
