Enamel Flashcards
where on the tooth is enamel thickest and thinnest
thickets - cuspal and incisal regions
thinnest - cervical regions
what part of tooth is enamel hardest
cuspal/incisal regions, hardness decreases as moves towards cervical region
what part of enamel is most mineralised
surface enamel = more mineralised and harder than deep enamel
basic units of enamel
enamel prisms / rods
what orientation to crystallites run in ‘rod regions/ head regions ‘ of enamel
parallel to rods
cross striations
horizontal banding on enamel rods showing daily enamel growth
striae of retzius
brow oblique stripes running across many rods of enamel representing weekly enamel formation
why does teeth whitening make enamel more fragile
removes organic component which is thought to give enamel some flexibilty
what happens when hydroxyapaptie has lots of carbonate (carbonated apatite)
it is more susceptible to acid attacks and therefore caries
hunter - schreger bands
only present in deep enamel ,banding patterns caused by periodic differing of orientation
‘gnarled enamel’
sometimes seen in cuspal regions
high concentration of rods makes them appear intertwined
may provide resilience during occlusal loads
enamel tufts
resemble tufts of grass
seen at ADJ
may represent hypomineralisation
enamel spindles
ondonto blast processes extending briefly into enamel from EDJ
have rounded ends
enamel lamellae
‘fault lines’
dark line crossing entirety of enamel , may show incomplete maturation of rods
where might a scalloped EDJ be found and why is this
may be found in cusp regions , is though to increase surface contact and therefore mechanical union between enamel and dentine
