Enamel Flashcards
What pathway do enamel prisms follow?
undulating path of ameloblasts 90 degrees to the ADJ.
Where do you find gnarled enamel?
at the cusps
What does gnarled enamel appear as?
prisms appear twisted around each other
What does gnarled enamel give the tooth cusp?
strength
Why do you get a better bond with subsurface enamel?
better etch pattern
What do incremental lines represent?
weekly growth
How may incremental lines be accentuated?
is systematically disturbed at birth
What neonatal lines?
when incremental lines are disturbed at birth
What are the shallow furrows where the striae reach the surface?
Perikymata
What are the ridges between perikymata?
Imbrication lines of Pickerill
What are enamel spindles?
dentinal tubules that extend into enamel
Where are enamel spindles best developed?
at the cusp
What is the relationship between enamel spindles to enamel prisms?
long axis of spindles is perpendicular to enamel prisms
What are the 3 origins of lamella?
- developmental
- acquired
- preparation artefact
What are tufts?
hypo mineralised and run in the same direction as enamel prisms
Where are tufts found?
at the DEJ
What are the 4 zones of enamel caries?
- surface zone
- body of lesion
- dark zone
- translucent zone
What is the 1st carious change?
translucent zone
What are the features of the translucent zone?
few large pores
loss of 1-2% mineral
What gives the translucent zone its appearance?
few large pores so resin (quinoline) gets in
What are features of the dark zone?
5-10% porosity
large and small pores
What gives the dark zone its appearance?
not penetrated by resin
What are features of the body of lesion?
25-50% porosity
What appearance does the body of the lesion have and why?
enamel is relatively translucent as resin permeates
