Amelogenesis

Inner enamel epithelium

• Cuboidal or low columnar
  
• Golgi bodies are located adjacent to stratum intermedium
  
• Mitochondria and other organelles are scattered throughout cytoplasm
  

Pre-secretory ameloblast

• Elongation of cells
  
• Golgi bodies moves centrally
  
• Nucleus shifts towards proximally (highly polarized)
  
• Rough endoplasmic reticulum increases
  

Initial secretory ameloblast

• Columnar cells
  
• Contain numerous secretory granules
  
• Secrete granules from distal end of cell forming initial enamel further away from DEJ
  

Secretory stage

• Tall columnar cells with Tome’s processes 
  
• Secretes roded enamel
  

Ruffle-ended ameloblast and smooth-ended ameloblast of maturation stage

• Cells shorten, decrease in volume and organelles
  
• Reformation of a typical basal lamina at the distal border
  
• Apexes alternate between smooth ended and ruffle ended border
  
• The three other enamel organ layers amalgamate and form papillary layer
  

Reduced enamel epithelium

• After maturation the cells of the outer enamel epithelium, stellate reticulum, and stratum intermedium lose their appearance
  
• They form a stratified layer of cells adjacent to the ameloblast
  
• Rough endoplasmic reticulum disintegrates during tooth eruption