An in vitro evaluation of fluorescein penetration into natural root surface carious lesions

In order to develop a method for detection and quantification of initial root surface carious lesions, the use of fluorescein sodium as a fluorescent dye is evaluated. The penetration depth of fluorescein sodium into human roots containing natural carious lesions was measured on approximately 130-mum-thick slices, cut in a direction perpendicular to the pulp. This depth was compared to the lesion depth that was measured on the same slice with transversal microradiography. The results indicate that fluorescein sodium in water penetrates into demineralized layers of root dentine even if a surface layer with a high mineral content is present. The penetation depth is about 1.1 times the microradiographically determined lesion depth.