odontogenesis

• odontogenesis


  tooth development
• Physiologic process

  1. initiation
  2. proliferation
  3. histodifferentiation
  4. morpho differentiation
  5. apposition
• initiation

  • 6th week of development
• stomodeum

  • called the primitive oral cavity
  • lined by stratified squamous epithelium called oral ectoderm or primitive oral epithelium
• dental ectomesenchyme

  • derived from neural crest
• primitive epithelial band

  • future dental arch
• dental lamina

  • represent the first sign of tooth development
  • ectodermal thickening
  • towards lingual surface
• proliferation

  • another ectodermal thickening labial/buccal to dental lamina known as vestibular lamina
  • 7th week
• oral epithelium

  • derived from ectoderm
• dental lamina - lingually

  vestibular lamina - bucally
• vestibular lamina

  • future oral vestibule
  • called "lip furrow band"
• BUD STAGE

  • beginning of dental organ formation
  • 8th weeks
• first molar - 4 months

  second molar - 1 year old

  third molar - 4-5 years old
• tooth bud


  further growth of epithelium into the underlying condensed connective tissue at 8th weeks
• enamel organ

  • future enamel
  • also called as dental organ
• ectomesenchymal cells start to cluster around the tooth bud resulting into a condensation of ectomesenchymal cells right beneath the bud/enamel organ producing dental papilla
• dental papilla

  • give rise to dentin and pulp
• cap stage


  tooth continue to proliferate laterally
• inner enamel epithelium (IEE)

  • cells that line the concave part of enamel organ
  • columnar epithelium
• outer enamel epithelium

  • cells that line the convex portion of the enamel organ
  • low columnar epithelium
• stellate reticulum


  network of star-shaped cells occupying the core of enamel organ, linked by desmosomes
• enamel knots

  • condensation of cells at the middle of enamel organ seen in IEE
  • determine the shape of the tooth
  • signal center that regulates cusp formation
  • determines the number, location of cusps of developing tooth
• enamel cord


  vertical extension of enamel knot
• enamel septum


  cord extended to make OEE
• enamel navel


  depression caused by meeting of OEE and IEE
• dental sac/ dental follicle

  rise of cementum, PDL, alveolar bone
• tooth germ


  contains enamel organ, dental papilla, dental follicle
• cells between IEE and OEE secretes glycosaminoglycans
• glycoseminoglycan


  hydrophilis resulting from pulling of water in surrounding
• desmosomes

  • gap junction
  • aka nexus
  • connects the star shape
• bell stage

  • 18 weeks
  • bell shaped
  • invaginations ni cap stage ay nagdedeepen
  • wala ng dental lamina
  • shape and outline of dental papilla is like the mesiodistal view at a mandibular incisor
  • final shaped of crown is fixed at this stage
• • as teeth continue to develop, they lose their connection with the dental lamina, they later break up by messenchymal invasion.
  • remnants of dental lamina persist as epithelial pearls or island within the jaw as well as in the gingiva. These are referred to as cell rest of serres
• cervical loop

  • IEE and OEE meets
  • significant for root formation
• dental lamina will be completely detach from oral epithelium that will form remnants
• cell rest of serres or epithelial pearls
• stratum intermedium

  • spindle or oval shaped
  • 1-3 layers of flat to cuboidal cells that is essential for enamel formation
  • between stellate reticulum and IEE
• morphodifferentiation


  determines the shape and size of the crown
• histodifferentiation


  differentiate of the cell

  cell of enamel organ differentiate into specialized cell
• membrana performativa


  membrane that seperates (ameloblast and odontoblast) enamel organ and dental papilla
• IEE will convert into tall columnar which is called the preameloblast that will induce/trigger preodontoblast na magiging odontoblast