The aim of the present study was a microscopic analysis of dens invaginatus with a cutting grinding system that allowed to obtain thin ground sections of undemineralized material. Cavities of about 1 mm were present in the bulk of the inner enamel and these cavities were lined by aprismatic enamel, by a basophilic lamellar material and by cuboidal cells of probable epithelial origin. Enamel in a more external location had an amorphous aprismatic appearance with the presence of basophilic rounded or lamellar calcifications with the appearance of Liesegang's rings. In one case the interradicular space was occupied by a large amount of a highly calcified bone tissue.