Cementum (Exam II) Flashcards
50-55% composition of cementum:
Organic
45-50% composition of cementum:
Mineral
Organic components of cementum include: (4)
- Type I collagen (Intrinsic & sharpey’s fibers)
- Proteoglycans
- Glycosaminoglycans
- Phosphoproteins
What are the functions of cementum? (3)
- Provides attachment for the 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 bone & dentin
Mineral
Unlike bone, cementum is ____, not _____, and contains no _____ or _____ canals
Avascular
Innervated
Haversian or Volkmann’s canals
Cementum is the _____ at the CEJ (30-50 micrometers)
thinnest
Cementum progressively increases in thickness to the 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, canaliculi)
Sharpey’s fibers (PDL)
Both indicated incremental growth & run longitudinally within the cementum
Depositional & reversal lines
Cementocytes contain ______ which are the space occupied by the cell & _____ 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 & compressive forces during tooth flexure
Abraction
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 ____ ares of the teeth and lesions are typically more ____ than ____
Cervical areas
Wide than deep
What teeth are most commonly affected by abrasion?
Premolar & cuspids
Calcified bodies appearing on or in the cementum and in the PDL
Cementicle
