Oral Histology & Development


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