Cementum Flashcards
what is cementum differentiated from
ectomesenchyme
does cementum have blood supply or innervation
neither
where is cementum thinnest
at the CEJ
what are the structural components of cementum and percentages
-45-50% mineral
- 50-55% organic
what does the organic material in cementum contain
type 1 collagen, proteoglycans, glycosaminoglycans, phosphoproteins
what are the functions of the cementum
-provides attachment for PDL
- may provide limited compensation for occlusal wear through continuous apical apposition
-may participate in repair of root fracture
where is cementum formed from
the inner zone of the dental folliclr
what do perforations in hertwigs root sheath allow for
the growth factors to leak out and make contact with dentin to then induce differentiation
describe depositional and reversal lines
indicate incremental growth and run from crown to apex
what are cementocytes and describe each
lacunae- space occupied by cell
canaliculi- space occupied by cytoplasmic projections, help with intercellular communication
what is the incidence rate of overlap, end to end, and gap between cementum and enamel
overlap-60%
end to end (30%)
gap (10%)
why is a gap between cementum and enamel bad
it leaves exposed dentin and sensitivity
what teeth are commonly affected in abfraction
single teeth with excursive interferences or eccentric occlusal loads
what is abrasion
loss of tooth structure by wear of dental tissue caused by abrasion of a foreign substance (toothbrush)
what teeth are affected in abrasions
canines and premolars in cervical areas
what is attrition
tooth to tooth contact on occlusal surfaces
what is a cementicle
calcified bodies appearing on or in the cementum and in the PDL
what causes cementicles
response to local trauma or hyperactive occlusion and appear in increasing numbers and increase in age
where are free cementicles, attached cementicles, and embedded cementicles found
free-floating around in the PDL
-attached- cememtum
-embedded- cementum
what are cemental spurs and what causes them
projection of cementum in response to trauma
why are cemental spurs bad
makes extraction hard
what is hypercementosis
excessive production of cellular cementum that generally involves the apical 1/3 of the root
what is the etiology of hypercementosis
trauma from occlusion, periapical inflammation, or compensation for occlusal attrition
what does hypercemetosis result in
bulbous root structure
why is cementum not supposed to be exposed to the oral cavity
due to perforations/rough surface/low mineral content
how does periodontal disease cause bone loss and results in exposed cementum
-exposed cementum is hypermineralized which prevents reattachment of collagen
-exposed cementum facilitates attachment of plaque and calculus
-exposed cementum facilitates endotoxin absorption
what is resorption and what is the cause
eating away of root surface. cause is unknown
what is repair due to
accessory canals
what do accessory canals allow for
vascular tissues to move and reach apical mineralized tissues
where are accessory canals located in multi rooted teeth
most common in furcation
where are accessory canals in single rooted teeth found and percentages in each
-near CEJ (1.6%)
-mid root (8.8%)
-apex (17%)
