510-10 Flashcards
What are the two models of tooth type determination
Field Model
Clone Model
Describe the Field Model
distinct overlapping fields of ectomesenchymal cells express very particular sets of HOMEOBOX genes that results in tooth differentiation.
Describe the Clone model
Ectomesenchymal cells (called the dental papillae) moves to the next tooth posterior at a certain developmental stage.
What will the vestibular lamina become?
Space between cheek and gingiva.
What are two types of invaginations in primary oral epithelium?
Vestibular and Dental Lamina
What will the condensed bud of the dental lamina eventually form?
The amenoblasts
At the Cap stage of development, what is the inside of the once bud region now called, and what is its function?
The Stellate Reticulum.
These cells pull fluid in, which expands the cells giving them their shape.
What is the Enamel Knot and when does it appear?
It’s a condensed organizing center and appears at the Cap Stage.
What are the 3 layers of the enamel organ?
IEE, OEE, and the Stellate Reticulum
cap stage
What establishes the crown pattern and at what stage?
Established by the folding of the IEE at the Bell Stage
this is the DEJ
What is the origination of enamel pearls?
It is the remnant of the dental lamina breaking off.
What defines the Apposition Stage?
The growth of Dentin and Enamel from the DEJ
What structure guides the development of the root?
Hertwig’s epithelial root sheath (HERS)
This is the junction of OEE IEE
Where are the Odontoblast Processes found?
against the dentin at the DEJ
Is the succedaneous lamina what’s left over from the Outer Enamel Epithelium?
I have no idea.
What is it called when neural crest cells mix with mesoderm?
Ectomesenchyme
What are the two main layers at 5-6 weeks in the jaw arches.
Primary epithelium and ectomesenchyme
Where do the successional teeth develop in relation to the permanent teeth?
Lingually
What are the 3 dental hard tissues and where do the come from?
Enamel - ameloblasts
Dentin - odontoblasts
Cementum - cementoblasts
What is the distinguishing characteristic of an ameloblast in the secretory stage?
Tome’s Process
What comprises 90% of enamel proteins
Amelogenins - they maintain the space between the rods.
Also have significant organizing and condensation role before withdrawing.
What comprises 10% of enamel proteins?
nonamelogenins - includes ameloblastin and enamelin
Describe the ameloblast ruffled and smooth stages
Alternate every 8 hours and depends on pH (more acidic lays down crystal in the ruffled stage)
80% of time spent in ruffled stage
20% time in smooth (higher pH) stage resorbing proteins (amelogenins)
What is Perikymata
The surface expression of the Striae of Retzius - which is thought to be either rhythms of enamel production or ameloblast proliferation stages.
What is the largest Striae of Retzius?
The neonatal line.
What is the precursor to odontoblasts?
Ectomesenchymal cells
How would you describe the incremental mineralization of dentin?
Globular and linear
What are the two main types of dentin that pertain to the odontoblast process?
Peritubular and Intertubular
Where are cementoblasts derived from?
Hertwig’s Epithelial Root Sheath (odontoblasts also come from here)
