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After the initiation of odontogenesis the stages of tooth development include
- bud stage
- the cap stage
- the bell stage
- and the maturation stage
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What happens in the apposition phase of tooth development
formation and maturation of the enamel, dentin and cementum
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Initiation->Bud->Cap->Bell->?
Apposition
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The initial teeth for both dentitions develop in the ______ followed later by _____ and then _____
- mandibular anteriors
- maxillary anteriors
- posteriorly in mandibular/maxillary
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The primary teeth develop during both the _____ and _____ period
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Most of the permanent dentition is formed during the
fetal period
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The first signs of tooth development are seen during the
6th to 7th week.
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The thickened oral epithelium is known as the
dental lamina
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The initiation stage, involves the process of
induction
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Induction is
the interaction between embryonic cells of the mesenchyme and the ectoderm
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All the teeth and their associated tissues develop from both
ectoderm and mesenchyme, with influence by the neural crest cells
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The basement membrane
An important acellular structure separates the oral epithelium and the mesenchyme (connective tissue) in the stomodeum
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Beginning in the 8th week, the oral epithelium grows deeper into the mesenchyme and is induced to produce a layer called
dental lamina
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Lack of initiation results in the absence of ______ called ______
- a single tooth or multiple teeth
- anodontia
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The areas most commonly affected with supernumerary teeth are
- Maxillary centrals (Mesiodens)
- Distal to the maxillary 3rd molars (distomolar)
- Premolar region (perimolar)
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The bud stage and occurs at the beginning of the
8th week
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The tooth germ is developed from
- the buds from the dental lamina and
- mesenchyme
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What is the only growth occurring in the bud stage
Proliferation
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Mishaped permanent third molar
Peg molar
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The cap stage occurs between the ____ and _____ weeks
9th and 10th
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What growth is occurring in the cap stage of tooth development
Proliferation differentiation and morphogenesis
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From these processes of proliferation, differentiation and morphogenesis in the cap stage, a depression occurs in the deepest part of each tooth bud of the dental lamina and forms
a cap or enamel organ
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Enamel is a product of what germ layer
Ectoderm
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Inner mass of mesenchyme deep to the bud
dental papilla
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The dental papilla will give rise to the
future dentin and pulp tissue
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The basement membrane between the enamel organ and the dental papilla is the site for the future
dentinoenamel junction (DEJ).
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The remaining mesenchyme surrounding the outside of the cap or enamel organ condenses into
the dental sac, or dental follicle
-
The dental sac will give rise to
periodontium, consisting of cementum, periodontal ligament and alveolar bone
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The tooth germ consist of what three structures
- enamel organ
- dental papilla
- dental sac
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In what week has initiation started for the anterior teeth in the permanent dentition
10th week
-
succedaneous teeth
Permanent teeth which replace primary teeth
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During the cap stage if the enamel organ abnormally invaginates into the dental papilla it will result in
dens in dente, or dens invaginatus
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______ usually leaves the tooth with a deep lingual pit
- dens in dente
- may appear as "a tooth within a tooth"
-
If a single tooth germ tries unsuccessfully to divide into 2 tooth germs it will result in
gemination
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The union of two adjacent tooth germs resulting in large, falsely macrodontic tooth is called
fusion
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The bell stage occurs during weeks ____ and ____
11th and 12th
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During the ____ stage differentiation occurs resulting in __ different cell types in the enamel organ
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What are the four different cell types in the enamel organ
- STELLATE RETICULUM
- STRATUM INTERMEDIUM
- OUTER ENAMEL EPITHELIUM
- INNER ENAMEL EPITHELIUM
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What kind of cells are in the outer enamel epithelium and what is it's purpose
- Cuboidal
- It will serve as a protective barrier for the rest of the enamel organ during enamel production
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What kind of cells are in the inner enamel epithelium and what does it give rise to
- columnar
- IEE will differentiate into enamel-secreting cells, ameloblasts
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The more outer ______ consisting of _____ shaped cells forming a ______ help _____
- stellate reticulum
- star
- network
- support the production of enamel
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The more inner ______ consisting of a compressed layer of _______ shaped cells help _______
- stratum intermedium
- flat to cuboidal
- support the production of enamel
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At the ____ stage, the dental papilla will undergo differentiation and form what two layers
- Bell
- outer cells & central cells of the dental papilla
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In the future, the outer cells of the dental papilla will differentiate into
dentin-secreting cells, odontoblasts
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In the future, the central cells are the
premordium of the pulp
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What happens during the apposition stage
during which the enamel, dentin and cementum are secreted in successive layers
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During apposition the _____, _______ and ______ are initially secreted as _____ which is ____
- enamel, dentin and cementum
- matrix
- extracellular substance that is partially calcified and serves as a framework for later calcification
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When the dental tissues subsequently fully mineralize occurs in what stage
maturation
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