THE CAPACITY OF DEVELOPING TOOTH GERM ELEMENTS FOR SELF-DIFFERENTIATION WHEN TRANSPLANTED

¹ Department of Anatomy, School of Medicine and Dentistry, University of Rochester, Rochester, N. Y.

1. Various portions of the soft tissues of the developing teeth of young female dogs have been transplanted to the ovaries or to the abdominal wall of the same animals.

2. In 18 experiments in which the odontoblast-pulp tissues were transplanted into the ovaries, the odontoblasts retained their form and produced histologically normal tubular dentin after 15 days implantation. The transplanted tissues showed no greater capacities for differentiation in the ovary than in the other sites of transplantation previously used.

3. Transplanted isolated enamel epithelium in 16 experiments was found to produce no organizing effect on the connective tissue fibroblasts of the ovary. In each case the enamel epithelium failed to maintain its cellular pattern and survived as stratified epithelium of the baso-squamous variety, which after 10 days implantation formed epithelium-lined cysts histologically similar to the simple epithelial cysts occurring in human jaws.

4. In 8 experiments odontoblast-free pulp tissue surrounded by enamel epithelium was transplanted into the connective tissue of the abdominal wall. Seven days following implantation the enamel epithelium had changed to the baso-squamous type which subsequently formed small epithelial cysts. This epithelium failed to induce any changes in the cells of the pulp tissue suggestive of odontoblast formation.

5. Evidence is presented which indicates that the enamel epithelium is not essential for maintaining the form of the dentin once a layer of calcified tissue has been deposited.

6. It is suggested that the failure of the enamel epithelium to stimulate odontoblast formation from the cells of the pulp tissue was due to the fact that once the ameloblasts begin the production of enamel they are no longer capable of influencing the connective tissue cells.