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Tooth development begins in the _____ and proceeds to the _____
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The inner enamel epithelium (IEE) will grow even more columnar and differentiate into
preameloblasts
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During the differentiation to preameloblast what is happened in the cells
the nucleus in each cell moves away from the center of the cell to a position farthest away from the basement membrane
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After the IEE differentiates into ______ the _____ of the dental papilla are induced by the _____ to become ______
- preameloblasts
- outer cells
- preameloblasts
- odontoblast
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The odontoblast begin _______ which is the ______ in their side of the basement membrane
- dentinogenesis
- apposition of dentin matrix, or predentin
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What happens to the basement membrane after the odontoblast differentiates
it disintegrates
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The _______ of the basement membrane causes the ______ and the _____ to come in direct contact with each other inducing the preameloblast to differentiate into ______
- disintegration
- preameloblasts
- predentin
- ameloblast
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The ameloblast begin ______ which is the _____
- amelogenesis
- apposition of enamel matrix
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The enamel matrix is secreted from _______ which is a _______ that faces the ______
- Tome's process
- tapered portion of each ameloblast
- defunct basement membrane
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With the enamel matrix in contact with the _______ mineralization of the _______ occurs forming the ________
- predentin
- disintegrating basement membrane
- dentinoenamel junction, DEJ
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The odontoblasts will leave attached cellular extensions in the length of the predentin called
odontoblastic process
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Each odontoblastic process is contained in a mineralized cylinder called the
dentinal tubule
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After the formation of the dentinoenamel junction, DEJ what happens to the cells in either side
They retreat away
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The cell bodies of the odontoblast will
remain within the pulp tissue
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The cell bodies of the ameloblast will
will be involved in the tooth eruption and mineralization process but will be lost after eruption
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Local enamel dysplasia may result from
trauma or infection of a small group of ameloblasts
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The structure responsible for root development is
the cervical loop
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The cervical loop is the _____ and consist of the ______ and ______ only
- most cervical portion of the enamel organ
- IEE
- OEE
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The function of Hertwig’s root sheath is
to shape the roots and induce dentin formation in the root area
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Explain the absence of enamel in the root
The root sheath induces odontoblastic differentiation but does not induce formation of ameloblasts because it is lacking the intermediate layers of the stellate reticulum and stratum intermedium
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When root dentin formation is completed the entire length of Hertwig’s root sheath
disintegrates
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After the disintegration of the root sheath, its cells may become the
epithelial rests of Malassez
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What happens to the epithelial rests of Malassez cells in the future
These groups of epithelial cells become located in the mature periodontal ligament and can develop into cysts in the future
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Misplaced ameloblasts can migrate to the root area causing enamel to be abnormally formed on the root surface forming
enamel pearls
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The apposition of cementum, or cementogenesis, in the root area also occurs when
Hertwig’s root sheath disintegrates
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The disintegration of the Hertwig’s root sheath allows
undifferentiated cells of the dental sac to come into contact with newly formed surface of the root dentin
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Contact of the dental sac cells with the dentin surface induces these cells to become immature
cementoblasts
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Cementoblasts become mature
cementocytes
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Many cementoblasts may become _____ by the cementum they produce
entrapped
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As a result of apposition of cementum over the dentin the ________ is formed
dentinocemental junction
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concrescence
- the union of the roots of two or more teeth through the cementum
- due to excess cementum formation
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The mesenchyme from the dental sac begins to form
the periodontal ligament (PDL)
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The formation of the PDL involves
forming collagen fibers that are immediately organized into the fiber bundles of the PDL
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The end of the collagen fibers in the PDL inserts into
the outer portion of the cementum and the surrounding alveolar bone in order to support the tooth
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What is dilaceration and what does it result from
- crown angulation in a formed tooth
- distortion of Hertwig’s root sheath due to injury or pressure
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After enamel apposition ceases in the crown area of each primary or permanent tooth, the ameloblasts place an acellular
dental cuticle or primary cuticle on the new enamel surface
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What is the reduced enamel epithelium (REE).
- Compressed layers of the enamel cells
- Outerenamel epithelium
- Stellate reticulum
- Stratum intermedium
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If a dentigerous cyst appears on an erupting tooth, it is called an
eruption cyst
-
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Where does the dentigerous cyst form
around the crown of a nonerupted impacted or developing tooth, most commonly the third molars
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dentigerous cyst or follicular cyst
An odontogenic cyst that forms from the REE after the crown has completely formed and matured
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What is Nasmyth’s membrane and what does it consist of
- A residue that may form on newly erupted teeth of both dentitions that may leave the teeth extrinsically stained
- the fused tissue of the REE and oral epithelium as well as the dental cuticle.
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The succedaneous permanent tooth erupts into the oral cavity in a position ________ to the roots of the shedding primary tooth
lingual
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The permanent maxillary incisors erupts into the oral cavity in a position more ______
facial
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During the eruption process as the REE and the oral epithelium touch they _______ which causes a release of _____ from the ____ that leaves an _______
- fuse
- enzymes
- REE
- epithelial tunnel
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As a primary tooth actively erupts into the oral cavity, the coronal portion of the reduced enamel epithelium ______ leaving the ______ portion still attached to the _____
- peels back off the crown
- cervical
- neck of the tooth
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The REE that remains near the CEJ after the tooth erupts then serves as the ________which creates a ______ between the tissue and tooth surface
- initial junctional epithelium of the tooth
- seal
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The initial junctional epithelium is later replaced by a _______ as the ______ is formed
- definitive junctional epithelium
- root
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During the process of primary tooth loss what is the function of the osteoclasts
absorb the alveolar bone between the exfoliating and erupting teeth
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During the process of primary tooth loss what is the function of the odontoclasts
cause resorption of portions of the primary tooth’s root of dentin and cementum as well as small portions of the enamel crown
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