Cementum- Exam II Flashcards
50-55% composition of cementum:
Organic
45-50% composition of cementum:
mineral
Organic components of cementum include: (4)
- Type 1 collagen (intrinsic & sharpey’s fibers)
- Proteoglycans
- Glycosaminoglycans
- Phosphoproteins
What are the functions of cementum? (3)
- provides attachment for PDL
- May provide limited compensation for occlusal wear through continuous apical apposition
- May participate in repair of root fracture
Cementum is ____ in origin
ectomesenchymal
Cementum contains less ____ than both bone and dentin
mineral
Unlike bone, cementum is _____, not _____, and contains no ____ or _____ canals
avascular; not innervated; no Haversian or Volkmann’s canals
Cementum is the _____ at the CEJ (30-50 micrometers)
thinnest
Cementum progressively increased in thickness to 90-150 micrometers at the ____ to 150-300 micrometers at the ____.
mid-root; apex
The cells responsible for the secretion of the organic matrix of cementum are derived from ______ cells that originate in the ______ zone of the _____.
Undifferentiated mesenchymal cells; proximal (inner) zone; dental follicle
All cells in the dental follicle are derived from:
ectomesenchyme (neural crest cells)
Differentiation is initiated with disruption of _____, allowing the undifferentiated mesenchymal cells to make contact with the adjacent dentin.
Hertwig’s epithelial root sheath
What is responsible for inducing the differentiation process in embryogenesis of cementum?
dentin matrix growth factors (BMP, FGF, DMP)
What are the histologic features of cementum?
Depositional lines
Reversal lines
Cementoblasts
Cementocytes- (lacunae and canaliculi)
Sharpey’s fibers (PDL)
Both indicate incremental growth and run longitudinally within the cementum:
depositional and reversal lines
Cementocytes contain _____ which are the space occupied by the cell. And _____ which is the space occupied by the cytoplasmic projections .
Lacunae; canaliculi
PDL fibers passing into acellular cementum:
Sharpey’s fibers
Loss of tooth surface at the cervical areas of teeth caused by tensile and compressive forces during tooth flexure:
Abfraction
Abfraction affects ____ areas of the teeth
buccal/labial cervical areas
Deep narrow V-shaped notch commonly affecting single teeth with excursive interferences or eccentric occlusal loads:
Abfraction
Loss of wear of dental tissue caused by the rubbing of foreign substances (like a toothbrush):
abrasion
Abrasion is usually located at _____ areas of the teeth and lesions are typically more _____ than _____.
cervical areas; wide than deep
What teeth are most commonly affected by abrasion?
Premolars and cuspids
Calcified bodies appearing on or in the cementum and in the PDL:
cementicle
What are the 3 classifications of cementicles?
free, attached, or embedded
A response to local trauma or hyperactive occlusion and appear in increasing numbers with increasing age:
cementicle
Exposed cementum is ____ which prevents the reattachment of ___
hypermineralized; collagen
Exposed cementum facilitates attachment of ___ & ___.
plaque and calculus
Exposed cementum facilitates:
endotoxin absorption
Cementum can play a role in:
periodontal disease
The excessive production of cellular cementum that generally involves the apical 1/3 of the root
hypercementosis
Etiology of ____ is variable involving such factors such as trauma from occlusion, periapical inflammaton, or compensation for occlusal attrition
hypercementosis
