1 - Tooth Development Flashcards
When is the 1st sign of tooth development?
6-7 weeks in utero
Deciduous teeth begin to calcify when?
13-20 weeks in utero
When have all deciduous teeth begin to calcify?
18-20 weeks in utero
Deciduous teeth erupt when?
6-30 months
What is the 1st part of the tooth to calcify?
Crown
What are the stages of tooth development?
- Crown formation
- Root formation
- Supporting structure formation
What arch is where the majority of teeth originate from?
1st arch
Teeth are particular from what process?
Medial-nasal process
The primary epithelial band corresponds to what?
Future dental arches
This is a horseshoe shaped band that corresponds to future dental arches
Primary epithelial band
The primary epithelial band gives rise to what?
- Dental lamina
- Vestibular lamina
What is expressed where the tooth bud will form?
Shh → epithelia
Pax9 → mesenchyme
The neural crest mesenchyme induces _____ to become the dental lamina
Oral ectoderm
What are the stages of crown formation?
Initiation → bud stage → cap stage → bell stage → enamel/dentin/pulp
In what stage do epithelial cells show no major changes?
Bud stage
What hormones are involved in placode formation (ectoderm thickening)?
Shh, Lef-1, Eda-Edar
Shh, Lef-1, Eda-Edar are in what stage?
Bud stage
The enamel organ and dental papilla are formed in what stage?
Cap stage
Do we see epithelial growth in the Cap stage?
Yes
In what stage do we see the tooth germ?
Cap stage
What does the tooth germ consist of?
- Enamel organ
- Dental papilla
What are the outer and inner parts of the dental papilla?
Outer = dentin
Inner = pulp
In what stage do we see Enamel knot formation?
Cap stage
This is a key signaling center that consists of a cluster of non-dividing cells determines cusp formation?
Enamel knot
What does the enamel knot determine?
Cusp formation
This is the enamel of the tooth
Enamel organ
Cells in the enamel organ synthesize what into the ECM?
Glycosaminoglycans
In what stage do we see glycosaminoglycans?
Cap stage
What synthesize glycosaminoglycans?
Cells of the enamel organ (IEE & OEE)
What do glycosaminoglycans do?
Hydrophilic and pull water into the enamel organ
You get stellate reticulum formation by what and in what stage?
Glycosaminoglycans pulling water in
Cap stage
What do glycosaminoglycans form?
Stellate reticulum cells
In what stage does the stratum intermedium form?
Bell stage
What stage does the crown attain full size and shape?
early Bell stage
Permanent detention forms _____ to the deciduous dentition
Lingual
The IEE and OEE are found in what stage?
Bell stage and cap
These will differentiate into ameloblasts
IEE
What will make odontoblasts and ameloblasts?
IEE
The site of what determines future cusp formation?
IEE differentiates
The junction of the IEE and OEE is called the
Cervical loop
This is the future site of the CEJ
Cervical loop
Dental papilla will form what?
Dentin
Pulp
Dental follicles will form what?
Cementum
Periodontium
In what stage do you see Tome’s process?
Secretory stage Amelogenesis
What breaks and then separates the tooth from oral epithelium?
Dental lamina
What proteins are associated with the secretory stage ameloblasts?
Amelogenin
Ameloblastin
Enamelin
What are the proteases in secretory stage ameloblasts?
Enamelysin
Kallikrein
In the secretory stage ameloblasts, what do they form?
Enamel rods and Inter-rod
This is the 1st layer of dentin formed
Mantle dentin
What are the characteristics of Mantle dentin?
- 1st formed
- Hypomineralized
- Only in the crown of the tooth
This is formed during tooth development at 4um/day
Primary dentin
This dentin is formed after tooth eruption
Secondary dentin
This dentin is produced in response to injury to protect the pulp
Tertiary dentin
IEE and OEE from the cervical loop proliferate downwards to form what?
Hertwig’s root sheath
What happened to HERS before cementum?
Most of it is removed before cementum is laid down
The hertwig’s root sheath is also the site of what?
CEJ
Differentiation of cementoblasts are from what?
HERS
Dental follicle cells
Remnants of hertwig’s are called
Epithelial rests of Malassez
What are the kinds of Cementum?
Acellular = line the root
Cellular = bottom of the root
What are the periodontal ligament fibers?
- Transseptal ligament
- Alveolar crest group
- Horizontal group
- Oblique group
- Apical group
- Interradicular group