DEH 103: Histology & Embryology

Chapters 7 & 8: Enamel and Dentin

Chapters 7 & 8: Enamel and Dentin

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Kelsie Orndorff

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Kelsie Orndorff

About these flashcards

This flashcard set covers advanced histology and embryology topics at the university level, focusing on the structure and formation of enamel and dentin in teeth. It delves into the composition of enamel rods, their arrangement, and various defects like enamel lamellae, tufts, and spindles. The set also explores the layers and types of dentin, including primary, secondary, and tertiary dentin, as well as incremental lines and Hunter-Schreger bands. Dental professionals and students will benefit from understanding these detailed aspects of tooth anatomy and development.

Flashcards

44

Students

1

Language

English

Category

Medical

Level

University

Created / Updated

04.01.2014 / 28.12.2021

What is the organic substance in enamel.

Enamelin (protein)

What cells produce enamel?

Ameloblasts

Where on a tooth is enamel the thickest / thinnest?

Thickest: Occlusal surface
Thinnest: CEJ

Where does enamel formation first begin?

DEJ

How many ameloblasts make up an enamel rod?

4 (1 head, 2 neck, 1 tail)

What is the name of the rod surface and rod center?

Sheath
Core

What helps make enamel resistant to fracture?

Rods interlock and the crystals lie on different axis

What is enamel at the cusp tips called?

Gnarled enamel

What are the light and dark bands that result becasue of light transmission?

Hunter Schreger bands

What are growth lines in enamel called?

Incremental lines

What is tehl ine of Retzius that is formed at birth?

Neonatal line

What is the visible crack in enamel called?

Enamel lamellae

What is the defect that forms when the dentinal tubule extends past the DEJ?

Enamel spindle

What is the enamel defect that passes through 1/5th of the enamel and looks like a tree limb?

Enamel tufts

What are the external enamel lines taht form due to termination of imbrication lines?

Perikymata

Where can prismless enamel be found on a tooth?

CEJ

When etched, which portion of the enamel rod is etched away?

Core

Which enamel defect can be a pathway for caries?

Enamel lamelae

Are enamel crystals larger or smaller than dentin crystals?

Larger

Why are primary teeth hard to apply dental sealants?

They are prisimless

Enamel is the hardest mineralized surface in the body becasue it is ___% mineralized.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

96

The 96% inoragnic mineral consists of? The 4% organic matrix and water consits of?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Hydroxyapatite: calcium phosphate
Protein enamelin

What is the range of thickeness of enamel?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

2.5 mm

Enamel is formed by ___ rods that extend from the surface to the DEJ.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

4 rods:
- 1 Head
- 2 Neck
- 1 Tail

When enamel rods are interwined at the cusp tip.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Gnarled enamel

These are alternating light and dark bands that extend perpendicular from the DEJ.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Hunter-Schreger bands

These are narrow brownish lines that enxtend diagonally outward from the DEJ toward teh occlusla/incisal part of the crown.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Incremental lines of Retzius (Striae of Retzius) (growth lines)

This is a noteable line of Rezius that is formed at birth. It is due to environmental and nutrition changes.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Neonatal line

These are cracks in the enamel surface visible to the eye that extend inward toward the DEJ. They can be casued by faults in enamel matrix or injury.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Enamel lamellae

These are microscopic defects that look like small brancehs attached to the DEJ and extend toward the surface of the enamel.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Enamel tufts

These are extensions of dentinal tubules into the enamel past the CEJ.

Enamel spindles

These are fine horizontal lines resulting from the termination of the Striae of Retzius.

Perikymata (Imbrication lines)

This is a band of ename that is noted on decidousus teeth and on permenent teeth near the CEJ. The enamel rods are nearly perpendiculat to the surface.

Prisimless enamel

These are teh natural spaces between rod crystals.

Micro-lamellae

The dentin makes up the bulk of the tooth what is it composed of?

70% inorganic hydroxyapetitie crystals
20% oganic collagen fibers and other proteins
10% water

What are the 3 classifications of dentin?

Primary: forms the body of the tooth
Secondary: forms after tooth eruption
Tertiary: reparative dentin

This is the mature pre-dentin.

Mantle dentin

This direclty underlies the mantle dentin.

Circumpulpal dentin

This is dentin found in some ares of most older teeth that is 2nd to trauma.

Sclerotic dentin

What is the layers of dentin around the dentinal tubules.

Intertubular dentin
Pretubular dentin
Dentinal tubules

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When etched, which portion of the enamel rod is etched away?

Core

Which enamel defect can be a pathway for caries?

Enamel lamelae

Are enamel crystals larger or smaller than dentin crystals?

Larger

Why are primary teeth hard to apply dental sealants?

They are prisimless

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