Ameloblasts are formed after:

AMELOGENESIS Ameloblasts begin enamel deposition after a few micrometers of dentin have been deposited at the dentinoenamel junction, At the bell stage, cells of the inner enamel epithelium differentiate. They elongate and are ready to become active secretory ameloblasts. The ameloblasts then exhibit changes as they differentiate and pass through five functional stages: (1) morphogenesis, (2) organization and differentiation, (3) secretion, (4) maturation, and (5) protection Golgi's apparatus appears centrally in the ameloblasts, and the amount of rough endoplasmic reticulum (RER) increases in the apical area. The row of ameloblasts maintains orientation by cell-to-cell attachments (desmosomes) at both the proximal and distal ends of the cell. This maintains the cells in a row as they move peripherally from the dentinoenamel junction depositing enamel matrix.