An immunocytochemical study of the human odontoblast process using antibodies against tubulin, actin, and vimentin

An immunofluorescence technique was applied at the light microscope level to human third molar coronal dentin in order to localize the intracellular components tubulin, vimentin, and actin. Third molars were split immediately upon extraction, and immersed in periodate-lysine-paraformaldehyde fixative. The crowns were demineralized, dehydrated, and wax-embedded, and 6-micron sections were prepared. The sections were post-fixed in -20 degrees C acetone, and then incubated with monoclonal mouse anti-tubulin, anti-vimentin, or anti-actin antibodies, followed by fluorescein-conjugated sheep anti-mouse immunoglobulins. Intratubular immunofluorescence labeling for tubulin and vimentin was very similar in pattern and intensity and extended to the dentino-enamel junction. In contrast, the actin labeling appeared less intense and more punctate, and was located primarily in the pulpal half of the crown, although some labeling was detectable up to the dentino-enamel junction. The presence of tubulin-, vimentin-, and actin-containing structures extending to the dentino-enamel junction supports the hypothesis that the odontoblast process does extend to the dentino-enamel junction in the human, and is in agreement with earlier studies of rat molars.