PPT 10 Tooth Development Flashcards
At 5-6 weeks, the maxillary and mandibular processes of an embryo have a thickened epithelium called the _____.
primary epithelial band
The embryonic connective tissue below the primary epithelial band is called _____.
ectomesenchyme
Two models explain how differently shaped teeth develop. They are called:
The Field Model
The Clone Model
The idea that there are distinct, graded and overlapping areas of ectomesenchymal cells for each tooth family, each expressing different combinations of genes, causing the development of differently shaped teeth is called ______
The Field Model
The idea that each tooth class is derived from ectomesenchymal cells programed by epithelium to produce teeth of a given pattern is called _____.
The Clone Model
At 6-7 weeks of development, the primary epithelial band begins to grow into the underlying ectomesenchyme forming 2 invaginations called the _____ and the _____.
vestibular lamina and dental lamina
The _____ will become the space between the cheek and gingiva.
vestibular lamina
Ectomesenchymal cells begin to condos around the dental lamina in a crescent shape and is called the _____.
dental papilla
The _____ stage is characterized by the folding of the dental lamina epithelium into the ectomesenchyme of the jaw.
bud
At about 10 weeks the bud develops into the hat shaped enamel organ which characterizes the _____ stage.
cap
In the cap stage, the enamel organ has 3 layers of cells called:
Outer enamel epithelium
Inner enamel epithelium
stellate reticulum
In the cap stage, elongated ectomesenchymal cells begin to form the _____ around the enamel organ and dental papilla. It will eventually develop into some of the supporting tissues of the tooth.
dental sac (aka dental follicle)
_____ are clusters of non-dividing epithelial cells in molar cap stage teeth. It is thought to be an organizational center for cusp development.
Enamel knots
The layer of ectomesenchymal cells in the Bell Stage next to the inner enamel epithelium will differentiate into _____ that will form dentin.
odontoblasts
A thick basal lamina is between the developing odontoblasts and _____ of the IEE.
ameloblasts
The stage after the cap stage where the enamel organ expands in size is called _____.
the bell stage
The enamel knot of the cap stage develops into an _____ in the bell stage.
enamel cord
A cancer-like growth of extra teeth is called ____.
odontoma
The _____ stage is identified by the production of enamel and dentin.
apposition
_____ is the collar of odontogenic epithelium formed from the apical margin of the enamel organ where the inner and outer enamel epithelia fuse. It surrounds the developing root and guides its morphologic development.
Hertwig’s epithelial root sheath
_____ are elongated columnar cells that make enamel.
Ameloblasts
The _____ is an epithelial structure that is responsible for the development of the permanent tooth.
succcedaneous lamina
The 4 stages of tooth development are:
- Bud Stage
- Cap Stage
- Bell Stage
- Apposition Stage
The permanent tooth develops _____ to the deciduous tooth.
lingually
The 3 simple stages of amelogenesis are:
- Presecretory stage
- Secretory stage
- Maturation stage
During amelogenesis the mineral content of the enamel _____ while the protein and water content _____.
increases, decreases
The 2 proteins produced by ameloblasts are _____ and _____.
amelogenins and nonamelogenins
_____ are a group of low molecular weight proteins that establish and maintain spacing between enamel rods in early stages of enamel development.
Amelogenins
2 types of nonamelogenins are _____ and _____.
Ameloblastin and Enamelin
_____ process secretes developing enamel during the secretory stage of amelogenesis.
Tome’s
During enamel maturation, ameloblasts alternate between smooth and ruffled morphology. During the ruffled stage they _____ and during the smooth stage they _____.
secrete, absorb
Shallow, periodic furrows on the outer surface of enamel are called _____.
perikymata
Surface perikymata correspond to the _____ that are seen in cross sections through enamel.
striae of Retzius
Large type I collagen fibers associated with fibronectin that originate between the odontoblasts and extend to the inner enamel epithelium are called _____.
von Korff’s fibers
Organic matrix predentin is deposited incrementally and its mineralization occurs in two ways. _____ calcification occurs relatively quickly in irregular patches while _____ calcification progresses slowly and evenly.
globular, linear
_____ is a source of cells for the dental follicle that become dentin-producing odontoblasts and cementum-producing cementoblasts.
Hertwig’s Epithelial Root Sheath (HERS)
The remnants of the disrupted epithelial layer of HERS become the _____.
epithelial rests of Malassez
