Steps of DEJ formation: 1. Formation of the _________. 2. Differentiation of cells in the dental papilla into _______. 3. Secretion of ______ by the odontoblasts. 4. Differentiation of the inner enamel epithelium into ________. 5. Secretion of the initial layer of enamel by ________.

1. Inner enamel epithelium 2. Odontoblasts 3. Mantle dentin 4. Ameloblasts 5. Ameloblasts

Dentinogenesis/Amelogenesis (Gonzales 1) Flashcards by Dakota Miller

Origin of dentin

Dental papilla

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Origin of enamel

The enamel organ

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What happens to the outer enamel epithelium?

Degenerates

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What happens to the inner enamel epithelium?

Forms enamel

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What happens to the stellate reticulum?

Allows room for growth

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What happens to the stratum intermedium?

Nutrition of the inner enamel epithelium

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Formation of the DEJ occurs during the _____ stage.

Bell

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Formation of the DEJ forms by reciprocal interaction (induction between the _____ and _____).

Epithelium

- Ectomesenchyme

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Steps of DEJ formation:

Formation of the _________.
Differentiation of cells in the dental papilla into _______.
Secretion of ______ by the odontoblasts.
Differentiation of the inner enamel epithelium into ________.
Secretion of the initial layer of enamel by ________.

Inner enamel epithelium
Odontoblasts
Mantle dentin
Ameloblasts
Ameloblasts

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Odontoblast differentiation: ______ derived from ectomesenchyme of neural crest origin lie next to the basement membrane of inner enamel epithelium.

Squamous cells

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Odontoblast differentiation: Squamous cells become _____ and develop ______ which extend toward the future DEJ. Contact with ________ initiates molecular signals that cause the cell to differentiate.

Columnar
Cell processes
Basement membrane

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Odontoblast differentiation: the ________ represents the location of the future dentino-enamel junction.

Basement membrane

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Odontoblast differentiation: During polarization, the nucleus _____ away from the cell process (and basement membrane) and takes on _______ of a protein secreting cell with well developed RER and golgi apparatus.

Migrates

- Organization

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Mantel dentin is a narrow band of dentin that is formed under the __________ of the inner enamel epithelium.

Basement membrane

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Formation of Mantle Dentin: thickness ranges between ______ and is a ______ step process.

10 to 50 micrometers

- Two

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Formation of Mantle Dentin: Secretion of the unmineralized organic matrix (pre-dentin) contains _______ and _______ then mineralization (inorganic matrix).

Glycosaminoglycans

- Dentin specific proteins

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Differentiating odontoblasts secrete _________ between developing cell processes.

Organic matrix (pre-dentin)

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Predentin is composed of _______, many of which are involved in the formation of hydroxyapatite crystals and _______, thick bundles of collagen fibers oriented perpendicular to the future DEJ. This induces formation of ________.

Numerous proteins
Korff fibers (alpha fibers)
Ameloblasts

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______ bud off cell processes of odontoblasts. These contain ________ needed for calcification of extracellular matrix.

Matrix vesicles

- Alkaline phosphatase and other enzymes

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Hydroxyapatite crystals outgrow from the ________.

Matrix vesicles

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Hydroxyapatite forms spheres, called _______, on the collagen fibers, which fuse to form ________.

Calcospherites

- Mineralized dentin

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Dentinal tubules are potential spaces in the dentinal matrix that contain _______, ________, and _______.

Odontoblastic cell process
Nerve endings
Extracellular fluid

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_______ represents all dentin formed after the initial formation of mantle dentin.

Circumpulpal dentin

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Formation of Circumpulpal Dentin: Retreating odontoblasts secrete small caliber collagen fibers called ________.

Beta fibers

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Formation of Circumpulpal Dentin: Mineralization occurs directly on the _______ in a linear fashion, called the __________.

- Collagen fibers | - Mineralization front

Formation of Circumpulpal Dentin: There is always a layer of _______ separating the odontoblast cell bodies from the mineralized dentin.

Pre-dentin

Mantle Dentin: - ______ micrometers next to DEJ - Contain ______ fibers - Mineralization by ______ - Induces formation of ________

- 10 to 50 - Alpha or Korff's (thick) - Matrix vesicle - Ameloblasts

Circumpulpal Dentin: - _____ of the dentin surrounding the pulp - Contains _______ fibers - Mineralization occurs on ________ and is mediated by _________.

- Most - Beta or thin collagen - Collagen fibers - Dentinal proteins

Enamel rods (prisms) made of ________, which are the area between ______ (horizontal striations).

- Rod segments | - Daily growth lines

The rod is separated by ______ that holds rods together. We now know that this is _______.

- Interrod (interprismic) substance | - Interprismic enamel aka interrod enamel

The enamel rod or prism is: - The structural unit of _______. - Composed of numerous _______. - Runs from the ______ to the ______. - Shaped like _______.

- Enamel - Rod segments - DEJ to the tooth surface - Keyhole

Life Cycle of Ameloblast: 1. Morphogenic Stage: _____ of tooth 2. Organizing Stage: _______ of cells 3. Secretory Stage: Secretion of _______ 4. Maturation Stage: _______ and _______ of enamel proteins 5. ______ and ______ Stage

1. Shape 2. Polarization 3. Enamel proteins 4. Mineralization and resorption 5. Protective and Desmolytic

Regulation of Enamel Structure: - Secretory Stage: build up of _______ - Maturation Stage: removal of _______

- Enamel layer | - Peptides

In the morphogenic stage, the interaction between _____ and _____ determines the shape of the tooth in the ___ stage.

- Ectomesenchyme and inner enamel epithelium | - Bell

In the organizing stage, ______ of the organelles away from the ________ to secrete proteins toward the future _____.

- Polarization - Basement membrane - DEJ

The formation of Tomes' process occurs during the _______ Stage.

Secretory

Formation of Tomes' Process: | 1. A layer of ______, which will become the future _____, is laid next to the basement membrane.

- Aprismic enamel | - DEJ

Formation of Tomes' Process: | 2. Enamel protein is secreted in the intercellular spaces between cells forming the _________.

Interrod or interprismic enamel

Formation of Tomes' Process: | 3. Portion of the cell surrounded by _______ becomes the Tomes' Process

Enamel

Formation of the Rod Space occurs during the ______ Stage.

Secretory

Formation of the Rod Space: 1. Cells retreat from DEJ while secreting additional _______ in the intercellular space contributing to the linear growth of the _______.

- Enamel proteins | - Interprismic enamel

Formation of the Rod Space: | 2. A potential space (Rod Space) containing the Tomes' process is located between the _______ of adjacent cells

Interprismic enamel

Formation of the Rod Segment occurs during the _______ Stage.

Secretory

Formation of the Rod Segment: 1. Space becomes filled with _____. 2. Results in ______ micrometer segment of enamel. 3. Multiple layers of rod segments form the ______. 4. Takes _____ to form a rod segment.

1. Enamel 2. 2 x 2 3. Enamel rods 4. 24 hours

______ are dark horizontal striations on the enamel rod that represent daily growth of rod segments.

Striations

Four ameloblasts make one enamel rod with keyhole shape due to ________.

Hexagonal shape of Tomes' process

Formation of Dentino-Enamel Junction: The surface of the mantle dentin is ______.

Not smooth

Formation of Dentino-Enamel Junction: Odontoblast cell processes extend beyond the dentin's surface, called _______.

Enamel spindles

Formation of Dentino-Enamel Junction: The _______ of inner enamel epithelium breaks down.

Basement membrane

Formation of Dentino-Enamel Junction: ________ secrete a layer of aprismic enamel.

Pre-ameloblasts

Formation of Dentino-Enamel Junction: Apical ends of odontoblast cells processes that become surrounded by enamel are called ______.

Enamel spindles

In the maturation stage of the life cycle of the ameloblast, _______ with hydroxyapatite occurs as well as resorption of _________ (alternating ruffled and smooth borders allow this).

- Mineralization | - Enamel proteins

Amelogenesis Imperfecta: List the three steps in the formation of enamel formation in which anomalies can occur

- Secretion - Calcification - Maturation

Amelogenesis Imperfecta: Secretion

Not enough enamel matrix is secreted

Amelogenesis Imperfecta: Calcification

Hypocalcification

Amelogenesis Imperfecta: Maturation

Crystal growth is limited

Hypoplastic Amelogenesis Imperfecta is a defect in ________, which is very thin and cannot be detected on radiograph. It results in a rough pitted surface, although enamel is hard and (+) calcification.

Amount of enamel secreted

Hypocalcified Amelogenesis Imperfecta is when ______ occurs. The matrix formation is of normal thickness, but enamel is soft ("swiss cheese") and teeth are usually brown due to extrinsic stains.

No calcification

Hypomaturation Amelogenesis Imperfecta is a defect in _______ in which enamel is softer than unaffected enamel but stronger that hypocalcified AI. Results in mottled enamel with brown pigment and snow capped incisal/occlusal surface.

Mineralization

In the protective stage of the life cycle of the ameloblast, the _______ is formed, which consists of _______ and ________.

- Reduced enamel epithelium | - Post-ameloblasts and stratum intermedium

______, which can be associated with unerupted or partially erupted tooth, are lined with epithelial cells derived from the reduced enamel epithelium.

Dentigerous cysts

In the desmolytic stage of the life cycle of the ameloblast, release of _______ during eruption to ________ occurs.

- Hydrolytic enzymes | - Break down connective tissue

Dentinogenesis/Amelogenesis (Gonzales 1) Flashcards

(62 cards)