Lec 7: Development of Dentition & Nolla's Flashcards
The primitive oral cavity is also called as?
Stomatodeum
The primitive oral cavity is lined by?
Stratified squamous epithelium
The lining of the stomatodeum is called as?
Oral ectoderm
The primitive oral cavity establishes connection with the foregut at what week of gestation?
4th week
This structure limits the stomatodeum, separating it from the foregut, until it ruptures at 4th week of gestation.
Buccopharyngeal membrane
The first indication of tooth formation is seen at what week?
6th week of gestation (1st trimester)
At the 6th week, the oral ectoderm proliferate into the underlying ectomesenchyme to form what horseshoe-shaped structure?
Dental lamina
The primary teeth develop directly from?
Dental lamina
The permanent successor teeth develop from?
Successional lamina / lingual extension of dental lamina
The permanent molars develop from?
Distal extension of dental lamina
Also known as the lingual extension of the dental lamina.
Successional lamina
At this stage, the enamel organ resembles a small bud, surrounded by the condensation of ectomesenchymal cells.
Bud stage
During the bud stage, what are the cells seen in the enamel organ?
- peripherally located low columnar cells
- centrally located polygonal cells
At this stage, the enamel organ proliferates to form a cap over the dental papilla. The dental papilla and dental sac become well defined.
Cap stage
During the cap stage, the enamel organ differentiates to form three epithelial cells, which are?
- Inner enamel epithelium
- Stellate reticulum
- Outer enamel epithelium
In this stage, there is an uneven proliferation of cells, resulting in deepening of the undersurface of the epithelial cap.
Early bell stage
What is the layer formed between the IEE and stellate reticulum during early bell stage?
Stratum intermedium
How many epithelial cell types does the enamel organ exhibit during early bell stage?
4 types
The IEE differentiates into tall columnar cells called?
Ameloblasts
These cells secrete enamel.
Ameloblasts
The peripheral cells of the dental papilla differentiate into?
Odontoblasts
These cells form dentin.
Odontoblasts
At this stage, odontoblasts form a layer of dentin and then the ameloblasts begin to secrete enamel matrix.
Advance bell stage
The deposition of enamel and dentin continues until?
Crown formation is complete
Root formation begins once the dentin and enamel reach the?
Future cementoenamel junction
The cervical portion of the enamel organ gives rise to the?
Hertwig’s epithelial root sheath
This structure molds the shape of the roots and initiates radicular dentin formation.
Hertwig’s epithelial root sheath
Eruption of a tooth generally begins when __________ of the root is formed.
two-thirds
Root formation is usually completed ________ after the eruption of tooth.
1–3 years
Physiological process involving the dental lamina and bud stage.
Initiation
Physiological process involving the bud and cap stage.
Proliferation
Physiological process involving the early bell stage.
Histodifferentiation
Physiological process involving the advanced bell stage.
Morphodifferentiation
Physiological process involving the formation of enamel and dentin matrix.
Apposition
Mineralization begins around at what week of gestation in primary dentition?
14th week
Mineralization occurs first in the?
Central incisors
The permanent tooth germs begin to form around what month of intrauterine life?
and their mineralization commences at ____?, beginning in the ______?
4th–5th month
birth
first molars
Radiographic studies of tooth formation consider what three basic stages?
Beginning of calcification, Crown completion, Root completion
Nolla’s Stage 1?
Absence of crypt
Nolla’s Stage 2?
Initial calcification
Nolla’s Stage 3?
1/3 of crown completed
Nolla’s Stage 4?
2./3 of crown completed
Nolla’s Stage 5?
Crown almost completed
Nolla’s Stage 6?
Crown completed
Nolla’s Stage 7?
1/3 of root completed
Nolla’s Stage 8?
2/3 of root completed
Nolla’s Stage 9?
Root almost completed
Nolla’s Stage 10?
Apical end of root completed
At what stage of Nolla’s classification do the eruption of tooth commence?
Stage 8 (2/3 of root completed)
