tooth development (from chart)

when does initiation occur?

6-7 weeks

what developmental process occurs during initiation?

induction

whats happening during intiation?

6 Week - 2 horseshoe bands of oral epithelium are formed from Neural Crest Cells

7 Week - Dental lamina formed (dental placodes -

earliest signs of a tooth)

Starts in the midline and goes posterior

what developmental disturbances happen in initiation?

Anodontia

Hyperdontia

Missing teeth or supernumeraries

when does bud stage occur?

8 weeks

what developmental process occurs during bud?

proliferation

whats happening during bud?

20 tooth buds develop into the ectomesenchyme

what developmental disturbances happen during bud?

microdonts and marcodonts

when does cap stage occur?

9-10 weeks

What developmental processes occur during cap?

Morphogenesis is the primary one

Proliferation & Differentiation are also happening

what is happening during cap?

Enamel Organ + Dental Papilla + Dental Sac = Tooth

Germ

10 week - permanent succedaneous teeth start induction process

what developmental disturbances happen during cap?

Fusion, Gemination, Dens in dente, Tubercle/Accessory Cusp

when does bell stage occur?

11-12 weeks

what developmental processes occurs during bell?

Proliferation, Differentiation, & Morphogenesis all occur

Differentiation happens to its full extent

What happens during the bell stage?

Enamel has 4 layers:

Outer Enamel Epithelium

Stellate Reticulum

Stratum Intermedium

Inner Enamel Epithelium

Dental Papilla undergoes extensive histodifferentiation and now has outer cells (become dentin) and central cells (become the pulp)

when does apposition/maturation occur?

final stages-varies by tooth

What developmental processes occur during Apposition and maturation?

Apposition: induction and proliferation

Maturation: maturation

What happens during the apposition/maturation stage?

Apposition: Enamel, Dentin, and Cementum are secreted in layers

IEE turns into preameloblasts (which secrete enamel through the Tomes process). The basement membrane disintegrates. Dental Papilla turns

into odontoblasts (which secrete dentin).

IEE + OEE = Hertwig's Root Sheath.

This disintegrates and forms the root of tooth. After root, the cementum is formed.

Maturation = dental tissues are fully formed and hardened

what developmental disturbances happen during maturation/apposition?

Enamel Dysplasia, Amelogenesis, Dentinogenesis, Enamel Pearls, Dilaceration, Concrescence, Supernumerary Root