Journal of Dental Research, Vol 75, 588-593, Copyright © 1996 by International & American Associations for Dental Research Online Journals
Evaluation of sodium fluorescein for quantitative diagnosis of root caries
M. H. van der Veen, H. Tsuda, J. Arends and J. J. ten Bosch
Laboratory for Materia Technica, State University Groningen, The Netherlands.
The diagnosis of root caries, in particular the judgment of the activity of
a visually observed lesion, is difficult. Quantitative determination of
lesion severity would allow the lesion to be monitored with time, so that
an indication of lesion activity could be obtained. This paper describes a
step in the development of a method that provides such a quantitative
determination. Specifically, fluorescein sodium salt is used as a
penetrating dye, the subject of study being the relationship between dye
concentration and porosity in demineralized root dentin. Fourteen human
third molars were demineralized in vitro (lactic acid CMC-gel, pH 5; in
each of 6 groups for 4, 7, 11, 14, 18, and 21 days). Fluorescein sodium
salt (0.2 g/L) was applied for 2 min. Thin slices (+/- 130 microns) were
cut from the root surfaces without water cooling. The dye fluorescence
radiance in the demineralized dentin was determined by means of a
micro-Raman spectroscope and compared with the mineral loss profiles
measured with transverse microradiography (TMR). The TMR data were
corrected for the difference in measurement area between the two
measurement systems. Corrected TMR profiles were compared with the
corresponding fluorescence scans, showing linear correspondence. The
correlation coefficient was r = 0.96. We conclude that, after uptake of
fluorescein sodium salt for 2 min, the dye concentration in an artificially
produced root-surface caries lesion is proportional to the amount of
mineral lost from that lesion.
