Wavelength-independent Microradiography: A Method for Non-destructive Quantification of Enamel and Dentin Mineral Concentrations using Polychromatic X-rays

Abstract

Wavelength-independent Microradiography (WIM), described in this paper, used polychromatic, high-energy (≤ 60 kV) x-rays for determination of mineral concentrations in tooth material non-destructively. This was done with the aid of a reference step-wedge made of 94% aluminum, 6% zinc. The mass attenuation coefficient of this material has a wavelength-independent ratio to the mass attenuation coefficients of enamel and dentin. With this method, mineral concentrations of enamel and dentin samples, with a thickness up to 500 μm, were determined at 20- and at 60-kV tube voltage. The samples were demineralized for 72 and 144 h and measured again. Comparison of the data showed that mineral quantification was within 1.5%, independent of the x-rays used. Finally, these mineral concentrations-obtained from the Wavelength-independent Microradiography-were compared with measurements of the same samples by Longitudinal Microradiography. A correlation of 0.99 was found for enamel and one of 0.96 for dentin.

Get full access to this article

View all access options for this article.

References

Angmar, B. ; Carlstrom, P. ; and Glas, J.E. (1963): Studies on the Ultrastructure of Dental Enamel. IV. The Mineralization of Normal Human Enamel, J Ultrastruct Res 8:12-23.

Arends, J. ; Schuthof, J. ; and Jongebloed, W.G. (1979): Microhardness Indentations on Artificial White Spot Lesions, Caries Res 14:190-195.

Brinkman, J. ; Ten Bosch, J.J. ; and Borsboom, P.C.F. (1988): Optical Quantification of Natural Caries in Smooth Surfaces of Extracted Teeth, Caries Res 22:257-262.

Carlstrom, D. (1964): Polarization Microscopy of Dental Enamel with Reference to Incipient Caries, Adv Oral Biol 1:255-296.

De Josselin DE Jong, E. and Ten Bosch, J.J. (1985): Error Analysis of the Microradiographic Determination of Mineral Content in Mineralized Tissue Slices, Phys Med Biol 30:1067-1075.

De Josselin DE Jong, E. ; Ten Bosch, J.J. ; and Noord-Mans, J. (1987a): Optimized Microcomputer-guided Quantitative Microradiography on Dental Mineralized Tissue Slices, Phys Med Biol 32:887-899.

De Josselin DE Jong, E. ; Van Der Linden, A.H. Lm ; and Ten Bosch, J.J. (1987b): Longitudinal Microradiography: a Non-destructive Automated Quantitative Method to Follow Mineral Changes in Mineralized Tissue Slices, Phys Med Biol 32 :1209-1220.

Ericsson, S.G. (1965): Quantitative Microradiography of Cementum and Abraded Dentin, Acta Radiol 246 (Suppl):1-37.

Featherstone, J.D.B. ; Ten Cate, J.M. ; Shariati, M. ; and Arends, J. (1983): Comparison of Artificial Caries-like Lesions by Quantitative Microradiography and Microhardness Profiles, Caries Res 17:385-391.

10.

Featherstone, M.J. and Silverstone, L.M. (1982): Creation of Caries-like Lesions in Sections of Teeth using Acid Gels, IADR Prog & Abst 61: No. 278.

11.

Graves, C.N. and Feagin, F.F. (1988): A Method of Semi-quantitative Microradiographic Analysis of Root Surface Lesion Remineralization, J Oral Pathol 17:241-249.

12.

Hodge, H.C. ; Bale, W.F. ; Warren, S.L. ; and Van Huysen, G. (1935): Factors Influencing the Quantitative Measurement of the Roentgen-ray Absorption of Tooth Samples. IV. Absorption Coefficient Factors, Am J Roentgenol Radium Ther Nucl Med 34:817-838.

13.

International Commission On Radiological Protection (1975): Report of the Task Group on Reference Man, Oxford: Pergamon Press, pp. 290-323.

14.

Koulourides, T. (1968): Experimental Changes of Enamel Mineral Density . In: Art and Science of Dental Caries Research, R.S. Harris , Ed., New York: Academic Press, pp. 355-378.

15.

Saloman, E.B. ; Hubbell, J.H. ; and Scofield, J.H. (1988): X-ray Attenuation Coefficients (Total Cross Sections) for Energies between 0.1-100 keV, Atomic Data and Nuclear Data Tables 38:1-197.

16.

Storm, E. and Israel, H.I. (1970): Photon Cross Sections from 1 keV to 100 meV for Elements Z=1 to Z=100, Nuclear Data Tables A7:565-681.