The document summarizes the development of teeth from early embryo formation through eruption. It describes how the odontogenic epithelium divides into the dental lamina and vestibular lamina in the primitive mouth of a 5 week old embryo. Tooth germs then form as solid bud-like outgrowths from the dental lamina, with each tooth germ containing an enamel organ that secretes enamel and a dental papilla of mesenchymal cells that secretes dentin. Cells within the enamel organ and dental papilla further differentiate into ameloblasts and odontoblasts that deposit enamel and dentin layers around the dental papilla. Finally, the tooth erupts through the gums, and cementum forms

1. Origin of Teeth

2. Odontogenesis
•It is a process by which tooth
moves within the jaw bones,
comes out into the oral cavity
•Primitive mouth of five week
old embryo
•Odontogenic epithelium -
primary epithelium band
divides into
• dental lamina
• vestibular lamina

6. Development of tooth
• Similar as in placoid scales; Enamel – epidermis ;Rest part of tooth - dermis or
mesenchyme

7. • Enamel organ – Dental lamina
• Dental follicle- ectomesenchymal cells enclosing rest of enamel
organ
• Dental papillae –ectomesenchymal cells filling up the concavity of
cap

8. • Thickening of ectoderm along the margin of the jaw bone
• Basal layer of ectoderm, the malphigian layer forms
continuous solid ridge like vertical invagination into
underlying dermis
Development of tooth

9. • This forms dental lamina which retains its connection with
the outer epidermis
• Mesodermal cells multiply rapidly beneath the ectodermal in
growth or dental lamina forming a series of solid bud-like
outgrowths at intervals called tooth germs
Development of tooth

10. • Their number is as many as no of milk teeth
• Each tooth germ, the inverted cup like epithelial cap will
secrete the enamel, hence termed enamel organ
• Mesodermal aggregation beneath enamel organ is termed
dermal or dental papilla
Development of tooth

11. • Its outer columnar cells become differentiated into
odontoblasts which secrete a layer of dentine on their outer
surface
• Cells of inner epithelial layer of enamel organ similarly
becomes ameloblasts which form a cap of hard enamel
around the top and sides of dentine
Development of tooth

12. • No enamel is deposited on the root
• Dental papilla is retained as pulp
• Its central cavity goes on increasing
to become the pulp cavity
• Nerves and blood vessels enter the
pulp cavity through the basal
opening
Development of tooth

13. • Upto this stage tooth remains inside the gum
(tissue)
• Later, its eruption through overlying
epidermis is known as cutting of tooth
• Around the root of teeth appears cement or
cementum which is modified bone
• Odontoblasts become inactive when tooth is
fully formed
• However in rodents, lagomorphs,
odontoblasts remain active throughout life
and teeth continue to grow
Development of tooth