There are many kinds of odontogenic diseases including odontogenic tumors and cysts, but the origin, time of development and growth have not been sufficiently studied. We therefore studied the expression of many kinds of cytokeratin in tooth germs in a few developmental stages. First, the optimum dilution rate for the anti-cytokeratin antibody (the primary antibody) was determined by in adult rabbits with many kinds of cytokeratin, such as (1) anti-human cytokeratin 8 (DAKO M631), (2) anti-human cytokeratin 10 (DAKO M7002), (3) anti-human cytokeratin 19 (DAKO M888) and anti-human cytokeratin 20 (DAKO M7019) immunohistochemically by means of the ABC method. The optimal dilution rates were * 50-100 for (1), * 50 for (2), and *40-80 for (4), but for (3), no satisfactory result was obtained at from a 25 to a 100 dilution rate. From these results, antibodies 1,2 and 4 and the above mentioned dilution rates were selected for use in this research.
10,25 and 30 day rabbit fetuses (age calculate
d from the day of copulation) were obtained. The numbers of these samples were 27,11 and 18, respectively. The lower jaws were cut from these fetuses and fixed in 10% formalin for two days. They were then paraffin-embedded, sliced to a 3 mu m thickness, stained immnunohistochemically and evaluated.
Results : As for cytokeratin 8, oral mucosa, dental lamina, inner and enamel epithelium and odontoblasts, all were positive in 20 day samples ; oral epithelium, inner enamel epithelium and odontoblasts were all positive in 25 day samples ; and oral epithelium was positive in 30 day samples.
As for cytokeratin 10, oral epithelium only was positive in every developmental stage. Cytokeratin 19 was negative in each tissue sample that we studied in every stage. As for cytokeratin 20, only oral mucosa was positive in 30 day samples. These results showed that there were differencies in the expression of each cytokeratin according to the developmental stage ; and it therefore seems that it may be possible to use this method in determining the time of development of odontogenic diseases. Less