Tooth Development Lecture Notes

Introduction

• Dental Lamina: Initiation point for tooth development.
  • Rapid proliferation of cells to form the Enamel Organ.
  • Responsible for developing all 20 deciduous teeth and 12 permanent molars.
  • Successional Lamina: Lingual extension that gives rise to 20 succedaneous teeth.

Morphological Stages of Tooth Development

• Stages are based on the shape/morphology of the enamel organ.

Bud Stage

• Oral Ectoderm: Proliferates into connective tissue forming the Dental Lamina.
• Dental Lamina to Enamel Organ:
  • Enamel organ is a round or oval localized growth of epithelial cells.
  • Resembles a flower bud, hence the name Bud Stage.
• Enamel Organ:
  • Separated by a basement membrane from ectomesenchyme.
  • Contains two types of cells:
    • Central cells: Polygonal shape.
    • Peripheral cells: Cuboidal or low columnar shape.
• Morpho-differentiation:
  • Change in shape of enamel organ observed.
  • No histo-differentiation – cells not yet specialized.

Ectomesenchymal Condensation

• Occurs as enamel organ forms, ectomesenchymal cells pack closely around and below.
• Reasons:
  • Increased mitosis of cells near enamel organ.
  • Migration of adjacent cells.
• Condensed Ectomesenchyme:
  • Later forms the Dental Papilla and Dental Sac.
  • Not yet distinguishable as distinct parts at this stage.