At the end of the crown stage, the enamel is completely formed. It is covered by the reduced enamel epithelium that protects the enamel of the dental follicle. All this lodged within the brink ripped. The roots formation started the proliferation of the epithelial cells of the cervical loop, located in the region of the cervical margin of the crown. This creates an epithelial sheath, which bends inwards to form hertwigs epithelial root sheath. Hertwigs epithelial root sheath is a bilayered cellular structure composed of an inner epithelial layer facing the dental papilla, and an outer epithelial layer facing the dental follicle. The apical bent portion of the sheath is named epithelial diaphragm. Its role is to induce the radiculadentinogenesis. For this, the happen, the diaphragm sends induction messages to the ectomyzen chymal cells of the apical papilla. These messages induce the differentiation of the ectomyzen chymal cells into adontoblasts. When newly formed root, adontoblasts then secrete the radiculadentin, and contact with the inner cells of hertwigs epithelial root sheath. Along the dentin matrix thus formed, the cells of the outer epithelial layer disintegrate, leaving only the inner epithelial layer. The cells of this sheath then synthesize and secrete enamel related proteins. For detaching from the root surface, the mantle dentin and enamel related proteins come thus directly in contact with the dental follicle, inducing the primary cementogenesis. For this purpose, cells of the dental follicle react to these induction signals, and differentiate either into fibroblastic cells that migrate towards the root surface with a perpendicular orientation, or into semontoblasts that parallel to the surface of the tooth. Then the fibroblastic cells secrete the extrinsic fibres, and the cementoblasts secrete the intrinsic fibres of the primary cementum. And that is how the dentin and the primary cementum of the root are formed.