Unit - 10 Enamel Flashcards
What are the chemical properties of enamel?
96% inorganic
1% organic
3% water
Is enamel vascular or non-vascular?
Non-vascular
How permeable is enamel?
Semi-permeable
How thick is enamel?
Approximately 2.5mm coming to a feather edge at the CEJ
How does enamel appear on radiographs?
Radiopaque
What functions does enamel provide surface for?
Mastication and speech
How many pounds of pressure per tooth can enamel stand?
20-30 pounds of pressure
Enamel clinical considerations
Attrition
Abfraction
Abrasion
Erosion
Caries
Enamel matrix is an ectodermal product because
Ameloblasts are derived from the inner enamel epithelium of the enamel organ, which was originally derived from the ectoderm of the embryo.
Does enamel contain collagen protein?
No
What unique classes of protein does enamel contain?
Amelogenins
Ameloblastin
Enamelins
Amelogenesis is the process of enamel formation that occurs during what stage of tooth development?
Apposition
What produces enamel during apposition?
Ameloblasts
What do ameloblasts actively pump into forming enamel matrix as it is being secreted by each of the Tomes processes?
Calcium hydroxyappetite
What intiates the development of the Tomes processes?
The movement of ameloblasts as it retreats from the first layer it deposited.
What is responsible for forming the prism shape found in enamel structure?
Tomes process
The Tomes process remains at the matrix producing end of the ameloblasts throughout the matrix production phase until
Just before the last layer of matrix is to be laid
The first and last layer of enamel is
Prsimless
Where is the first wave of enamel matrix located?
At the incisal or occlusal surfaces near the DEJ
Where is the second wave of enamel matrix located?
Overlaps the first with the entire process moving cervically to the CEJ
What are the clinical considerations during enamel formation?
Developmental disturbances
Pit and groove patterns
What happens to the hydroxyappetite crystals during the maturation phase of enamel development?
They grow and coalesce with each other
The remnant matrix must now be _______ to allow full mineralization to occur
Removed
The ameloblasts will now take on a new function, a cell capable of
“Digestion” removing the matrix remnants and water.
The crystals continue to grow until
Enamel is 96% mineral content
Does enamel mineralization continue after the eruption of the tooth?
Yes
The post-eruption maturation is due to
The deposition of minerals, such as fluoride and calcium, from saliva into hypomineralized areas of enamel
The last product the ameloblasts spews out is called the
Enamel Cuticle or Nasmyth’s Membrane
Each ameloblasts forms the body of one rod, and at least three more adjacent ameloblasts continue to the interrod enamel that makes up the
“Tails” of the “keyholes”
An optical phenomenon visualised when a cut or fractured enamel surface is viewed under reflected light. These bands demonstrate the synchronous decussation of individual or groups of enamel prisms
Hunter-Shregar Bands
What happens to the enamel during whitening?
A chemical reaction carrying out an oxydizing reaction in the enamel and dentin.
Basic structural component of enamel
Interrod enamel
Incremental growth lines or bands as seen in enamel
Incremental Lines of Retzius
Where the margin of each enamel layer reaches the free surface of the enamel, a fine ridge is seen in recently erupted teeth
Imbrication Lines or Perikymata
The transition from an intra to an extra-uterine environment leaves its mark in deciduous teeth and first molars as an accentuated enamel incremental ring called
Neonatal lines
Short, linear defects found at the DEJ and extend into the enamel often being more prevalent at the cusp tips
Enamel spindles
Closed cracks or defects which, in their manner of propagating, act to prevent enamel fractures
Enamel tufts
Fissure-like defects that extend along the longitudinal axis of the tooth down to the dentin layer
Enamel lamella
