Journal of Dental Research, Vol 69, 1519-1521, Copyright © 1990 by International & American Associations for Dental Research Online Journals
Root hard-tissue demineralization rate measured by 125I absorptiometry: comparison with lesion-depth measurements
H. Almqvist, J. S. Wefel and F. Lagerlof
Department of Cariology, Karolinska Institutet, School of Dentistry, Huddinge, Sweden.
The aim of the present study was to compare demineralization of root hard
tissue, monitored by 125I absorptiometry, with lesion-depth measurements
under polarized light microscopy. The intact roots of ten human molars,
which had not been exposed to the oral environment, were divided into 39
cementum/dentin blocks and exposed to a buffer solution of pH 4.5
containing 2.2 mmol/L calcium and inorganic phosphate. After
demineralization for 3.5, 7, 14, and 21 days, transmission measurements by
125I absorptiometry were performed, and one block from each tooth was taken
out of the solution for lesion-depth measurement. The results showed a high
degree of correlation (r = 0.952) between lesion depth and change in
transmission, with a more rapid increase initially in both variables. A
linear relationship with the square root of time was found. Conversion of
transmission data to lesion-depth data was possible when this caries model
system was used on cementum dentin blocks.
