A computer-assisted videodensitometric method to visualize mineral distributions in in vitro and in vivo formed root caries lesions

Abstract

A computer-assisted videodensitometry (CAV) method is presented for the microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as essential steps (1) image digitizing by a CCD camera, (2) conversion of gray values to equivalent aluminium thicknesses and (3) conversion of aluminium thickness to vol% of mineral. Procedure and accuracy are described. The CAV method is illustrated for dentin lesions formed in vitro as well as for clinical root caries lesions. The CAV method is especially advantageous for clinical lesions because it can be employed for very complex mineral distributions and irregular lesion outlines. In given areas of interest, the mineral distribution (in vol%) can be plotted in 3D form in pseudo-colors. Conventional microradiographical profiles can be obtained directly from the CAV images. For in vitro lesions, the mineral distribution parameters, lesion depth, mineral loss, and mineral acquisition values can be generated from CAV images with a reproducibility of better than 7%. The CAV method is a valuable tool in quantitative mineral studies of clinical lesions in extracted teeth as well as in in situ lesion investigations. © Munksgaard 1997.