The membrane that separates the enamel organ and the dental papilla just prior to dentin formation is called:

 # The membrane that separates the enamel organ and the dental papilla just prior to dentin formation is called:

A. Inner enamel epithelium

B. Outer enamel epithelium

C. Membrana preformativa

D. Cell-free zone

The correct answer is C. Membrana preformativa.

The dental papilla is enclosed in the invaginated portion of the enamel organ. Before the inner enamel epithelium begins to produce enamel, the peripheral cells of the mesenchymal dental papilla differentiate into odontoblasts under the organizing influence of the epithelium. First, they assume a cuboidal form; later they assume a columnar form and acquire the specific potential to produce dentin. The dental papilla ultimately gives rise to dental pulp, once the dentin formation begins at the cuspal tip of the bell stage tooth germ. The basement membrane that separates the enamel organ and the dental papilla just prior to dentin formation is called the membrana preformativa.