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43 Cards in this Set

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Enamel characteristics:

-Hardest calcified tissue in the body


-Avascular and has no nerved in it


-Non vital and can be lost forever


-can be removed by diamond burs

What is mature enamel?

Crystalline formation consisting mainly of calcium hydroxyapatite

What is hydroxyapatite made up of? (formula)

CA10(PO4)6(OH)2

What are the percentages of hydroxyapatite?

-96% mineralized or inorganic material


-1% organic material


-3% water

What does enamel functionally?

-hard surface for mastication


-speech



Enamel is the only portion of the tooth seen clinically in a healthy mouth because?

it covers the anatomical crown

On xrays enamel appears more?

Radiopaque (lighter) than dentin and the pulp which are more radiolucent.

What is a goal of a dental professional for enamel?

preservation

What are ways enamel can be lost? (5)

-attrition (tooth to tooth contact)


-abrasion (friction from excessive tooth brushing and abrasive toothpaste)


-erosion (loss by chemical means)


-caries


-abfraction (enamel pops off at cervical region)

What is amelogenesis?

process of enamel matrix formation that occurs during the apposition stage of tooth development.

Enamel matrix is produced by?

ameloblast cells

ameloblasts are columnar cells that change during?

the apposition stage

________are differentiated in the crown area ONLY.

Ameloblasts

Enamel is confined to the?

crown area of the tooth

Enamel matrix is secreted from?

Tomes' process

Tomes' process is a tapered portion of each ameloblast that faces the disintegrating basement membrane and forming which junction?

Dentinoenamel junction (DEJ)

Dentinal Tubule has?

Adonotoblast

________ _________ is an ectodermal product

Enamel matrix

Why is enamel matrix an ectodermal product?

-Ameloblast derive from IEE of the enamel organ


-IEE was derived from ectodermal layer of embryo

EARLY enamel matrix is only

partially mineralized

Early enamel matrix is made up of?

-30% mineralized


-composed of proteins, carbohydrates and only a small amount of calcium hydroxyapetite crystals.

Ameloblast transports?

Minerals

Enamel matrix is first formed in?

The Incisal and occlusal portion of the tooth.

The first wave of enamel apposition moves to?

the future outer enamel surface

The second wave of enamel apposition?

overlaps the first wave

Wave patterns continue and move in which direction?

Cervically to the cementoenamel junction (CEJ) Top to bottom

Enamel mineralization stage covers which two stages of tooth development?

-apposition stage and maturation stage

Enamel mineralization continues after?

Eruption of the tooth

During maturation stage ameloblast does what?

-Actively pumps calcium hydroxyapetite into partially mineralized enamel matrix.


-They withdraw an equal amount of organic materials

What happens After ameloblasts are finished with enamel apposition and enamel maturation

They become part of reduced enamel epithelium (REE) along with other portions of the compressed enamel organ.

The reduced enamel epithelium (REE) fuses with the oral mucosa creating?

a canal to allow the enamel cusp tip to erupt through the oral mucosa into the oral cavity.



The reduced enamel epithelium (REE) causes ameloblast to?

be lost forever preventing any further apposition

What happens after the tooth erupts into the oral cavity?

Post eruption maturation takes place due to a depositing of minerals (fluoride/calcium) from saliva into hypomineralized areas of enamel.

Enamel rods are also called?

enamel prisms

Enamel rods are the crystalline _______ ________ of ________

structural unit of enamel

Enamel rods extend the width of enamel from ___ to the outer_______ _________

DEJ; Enamel surface

Each enamel rod is somewhat perpendicular to the ________ and ______ _______ ______

DEJ; outter enamel surface

Enamel is the thickest and the rods are longer in what part of the tooth?

Cusp incisal edges

Enamel is thinner and the rods are shorter in what part of the tooth?

Centinoenamel Junction

Enamel rods show varying degrees of curvature from _____ to _____ _________ _________

DEJ; outer enamel surface

What are the three shapes of enamel rods?

-cylindrical


-4 micrometers in diameter


-head and tail

Perikymata are?

grooves

Neonatal line is?

metabolic changes at birth