Enamel Flashcards
Where is the thickest and hardest region of enamel?
Cusps/incisal edges
What is the basic unit of enamel?
Enamel rods/prisms
Where are rods deposited in elation to the ameloblast membrane?
Deposited at right angles to the ameloblast membrane.
What makes up 95% of enamels weight?
Hydroxyapatite (the inorganic component of enamel)
1% weight made up of the organic component i.e. the proteins in the matrix.
What is responsible for rod and interrod areas of enamel?
Tomes process on the ameloblast. (distal projection on the ameloblast)
What makes enamel stronger and less susceptible to acid attack?
The OH in the hydroxyapatite being substituted with Fluoride
What can enamel crystals NOT grow without?
Calcium phosphate
List the optical features of enamel.
Sinusoidal ‘S’ shape of the enamel rods.
Hunter schreger bands
Gnarled enamel
Striae of retzius
(Subdivisions of SofR)
Perikjmata
(Subdivisions of SofR)
Neonatal lines
What are Hunter Scherger bands? What is there purpose?
Enamel rods that are deposited in bands of varying thickness.
Strengthen enamel and prevent cracks from propagating through the tooth.
What is gnarled enamel? Where is this found? What is the purposed of it?
Highly concentrated areas of enamel rods found in cusp tips and incisal edges.
Strengthens enamel.
Where are Hunter Scherger bands not found?
Absent in outer enamel.
What are striae of Retzius?
Incremental growth lines in enamel
What are Perikjmata?
Extensions of striae of retzius that extend on to the outer surface of enamel.
What are neonatal lines?
A type of striae of retzius that appears darker than the other bands.
Identifies the enamel formed before birth and after birth.
What structures are found at the ACJ?
Enamel tufts
Enamel lamellae
Enamel spindles
