Tooth development Flashcards
What is tooth enamel derived from
Ectoderm
What are all parts of the teeth derived from aside from enamel
Ectomesenchyme
Where do teeth develop from
‘Tooth germs’
Where does neural crest tissue migrate into
Developing face and jaw
When does the primary epithelial band develop
approx 6 weeks
When does the dental lamina develop
Approx 7 weeks
What does the PEB divide into
Vestibular lamina
Dental lamina
What does the vestibular lamina break down to form
Buccal sulcus
What does the dental lamina form
The enamel organ develops from the dental lamina
What does IUL stand for
Intra uterine life
What forms during the ‘cap’ stage
External enamel epithelium
Internal enamel epithelium
Where does the external and internal enamel epithelium meet
Cervical loop
Why is the ‘cap’ stage named as so
The enamel organ forms a ‘cap’ over the papilla
What occurs during the ‘bell-stage’
More cell layers become differentiated
Tooth shape is being defined
What are the 4 cell layers present at the ‘bell’ stage
Stratum intermedium
Stellate reticulum
Internal enamel epithelium
External enamel epithelium
When does late ‘bell’ stage occur
Approx 18 weeks IUL
What occurs during late ‘bell’ stage
Crown shape is well defined
Apposition of enamel and dentine begins
Dentine formation established
Enamel formation beginning
Formation ofdentine and enamel
Dental papilla cells adjacent to the IEE differentiate into odontoblasts
Odontoblasts lay down dentine matrix (pre dentin), which is later mineralised
Once dentine formation has begun, IEE cells differentiate into ameloblasts, which form enamel
What occurs during detinogenesis
-Odontoblast differentiation from IEE
-Deposition of dentine matrix (mainly collagen)
-This unmineralized dentine is predentine
-Mineralisation of dentine (hydroxyapatite)
What do ameloblasts produce
Enamel
What are the 2 stages of enamel formation
- Protein matrix deposited (around 30% mineralised)
- The organic part is then removed and mineralisation is completed The ameloblasts change form and function several times during amelogenesis
What happens to ameloblasts over time
Differentiation
Secretion
Maturation
Regression
What are the stages of amelogenesis
Ameloblast differentiation
Secretory phase
Maturation phase
Protection phase
What occurs during ameloblast differentiation
Dentine induces IEE cells to differentiate into ameloblasts
they elongate, becoming columnar
the nucleus migrates to the basal end of the cell
