Cementum Flashcards
what si cementum
mineralised tissue
etomesenhcymal (detail follicle origin)
tooth support
cover roots
what is the composition of cementum (mineral, matrix and water)
mineral - 65%
matrix - 23%
Water - 12%
how does cement differ from bone in respect to cells
cementum has <100Um live cells and >100Um dead cells
bone has all living cells
how does cementum differ to bone in respect of blood vessels and nerves
bone has blood vessels and nerves incorporated whilst cementum doesnt
what s of clinical importance of cementum vs bone remodelling
cementum is resistant to resorption but if late force will resorb
bone is easily remodelled imp in ortho
what cells are alive in cementum
cells close to surface (PDL) as near a blood supply as deeper they die
what ar the different ways a cementum can be around the cervical margin of a tooth
overlap 60%
but joint 30%
doesnt meet ervical margin (sensitivity) 10%
what si root development riven by
HERS
what des HERS actually do
apical dev of inner and outer enamel epi root morphology inductive proliferates disintegrate
what does HERS induce
root dentinogenesis
cementogenesis
where does HERS proliferate and disintegrate
proliferate - apically
disintegrates - cervically
how can some hers cells form cementobalast
epi/mesenchymal transformation
what are the 9 steps in cementum formtion
1 - HERS induces odontoblasts form
2 - predentine then dentine form HERS basal lamina breaks down
3 - Hers = enamel matrix P on to predentie
4 - EMP mineralise = hyaline layer
5 - Hers disintegrates
6 - induce follicle cells migrate to root surface and form cemetnoblasts
7 - cemnoblasts = cementum and retreat out
8 - cementum mineralise trap PDL
9 - cell rest malaise
where is the hyaline layer of hopewell smith
between dentine and cementum
is the hyaline layer mineralised
highly
how think is the hyaline layer
10 UM
what si the origin of the hyaline layer
matrix from
- epi cells - EMP
- ectomesenchymal cells
what is the role of the hyaline layer
induces cementoblast formtion
cements cementum onto tooth
what si the cementoblast origin
Dental follicle maybe hERS (from eli-mesenchymal transformation)
what does the cementoblasts do in cemeitogeneis
migrate out
depo matrix
mineralise
trap PDL fibres
what does he matrix consist of
collagen
ground sub
are there matrix vesicles in mineralisation of cementum
no
what are the classification of cells
cellular
acellular
what are the features of acellular cementum
no cells
slow depo
close incremental lines
narrow precememtun
