Stages of tooth development Amjad al.bleahid

Introduction •The developmental stages are based

on the shape of the epithelial part (ectodemal component) of the developing tooth germ

•These stages are called the bud, cap & the bell stages

A tooth germ consist of three parts 1-An enamel organ, which is derived

from the oral ectoderm

2- A dental papilla, which is derived from the ectomesenchyme

3-A dental sac, which is also derived from ectomesenchyme

A) Enamel organ

1-Outer enamel epithelium 2-Inner enamel epithelium3-The stellate reticulum

B) Dental papilla

•It is a condensation of the ectomesenchyme at the epithelial concavity (Cellular condensation)

c) Dental sac

•There is marginal condensation of the ectomesenchyme surrounding the enamel organ & dental papilla (Cellular condensation)

• The enamel organ produces enamel

• Dental papilla produces dentin & pulp

• Dental sac produces cementum, periodontal ligament & alveolar bone

Stages of tooth development

•1-Bud stage

•2-cap stage

•3-bell stage

1-Bud stage • At certain points along the dental lamina• At the site of the future deciduous teeth

• The epithelial cells proliferate to form little buds called enamel organ which grow into the ectomesenchyme

2-Cap stage •There is uneven growth of the bud, as

the outer margins grow faster than its center which leads to change in the shape of the tooth germ to be in a cap form

3-Bell stage•Continued uneven growth of the tooth

germ leads to the next stage of tooth development, the bell stage give tow stages :

•1-Early bell stage •2-late bell stage

A) Early bell stage (Histodifferentiation and

morphodifferentiation) the tooth crown assumes its final shape

B) Late bell stage• (appositional stage), this stage is

associated with the formation of dental hard tissues

Review

• The enamel organ produces ……………

• Dental papilla produces ……………. & ……………

• Dental sac produce …………… , ……………… & ………………

References •Avery, J.K., Daniel, J & Chiego, Jr:

Essential of Oral Histology and Embryology. A clinical Approach 4th ed 2013

•Avery, J.K. : Oral development and Histology, 3rd ed New York Thieme 2002

Thank you