A COMPUTER-ASSISTED VIDEODENSITOMETRIC METHOD TO VISUALIZE MINERAL DISTRIBUTIONS IN IN-VITRO AND IN-VIVO FORMED ROOT CARIES LESIONS

A computer-assisted videodensitometry (CAV) method is presented for th e microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as e ssential 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 de scribed. The CAV method is illustrated for dentin lesions formed in vi tro as well as for clinical root caries lesions. The CAV method is esp ecially advantageous for clinical lesions because it can be employed f or very complex mineral distributions and irregular lesion outlines. I n given areas of interest, the mineral distribution (in vol%) can be p lotted in 3D form in pseudo-colors. Conventional microradiographical p rofiles can be obtained directly from the CAV images. For in vitro les ions, 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 teet h as well as in in situ lesion investigations.